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COMPARISON BETWEEN WET AND DRY METHODS OF STARCH EXTRACTION FROM FRESH SAGO PITH
Jenefer James Moinsol
TP 1
7 Bachelor of Science with Honours J51 (Resource Biotechnology) 2013 2013
I
Pusat Khidmat MakJumat Akademik VNlVERSm MALAYSIA SARAWAK
I
PKHIDMAT MAKLUMAT AKADEMIK
1111111I11~iffilllllllll 1000246769
Comparison Between Wet And Dry Methods Of Starch Extraction From Fresh Sago Pith
Jenefer James Moinsol 26505
A final project report submitted in partial fulfilment of the requirement for the degree of Bachelor of Science with Honours
(Resource Biotechnology)
Supervisor Professor Dr Kopli Bujang
Department of Molecular Biology Faculty of Resource Science and Technology
University Malaysia Sarawak 2013
DECLARATION
I hereby declare no portion of the work referred in this project has been submitted in support
of an application for another degree qualification of this or any other university or institution
of higher learning
---------~--------------------(Jenefer James Moinsol) Resource Biotechnology Department of Molecular Biology Faculty of Resource Science and Technology University Malaysia Sarawak
ACKNOWLEDGEMENTS
First of all I would like to express my deepest appreciation to God the highest for His
blessing and for granting me the strength to accomplish my final year project A special
thanks and sincere appreciation dedicated to my supervisor Professor Dr Kopli Bujang for
all the advice and support throughout this project Special thanks also dedicated to Assoc
Prof Dr Cirilo for his guidance
Millions thanks dedicated to postgraduate students of the Biochemistry Laboratory Faculty
of Resource Science and Technology especially to Miss Rubena Malfia Kamal and Miss Nur
Jannah for their great support and advice throughout accomplishing this project
Next I would love to deliver my sincere gratitude to my family for their encouragement and
understanding during the development of this project Last but not least my greatest
appreciation to all my course mates and friends for their support and motivation
11
Pusat Kbidmat Maklumat Akademik UNIVERSm MALAYSIA SARAWAK
T ABLE OF CONTENTS
Declaration
Acknowledgement
Table of contents
List of Figures
List of Tables
List of Abbreviation
Abstract
Abstrak
10 INTRODUCTION
20 LITERATURE REVIEW 21 General Introduction of Sago Palm 22 Starch Content
23 Productivity and Production of Sago Starch 24 Conversion of Sago Starch Sugar 25 Hydrolysis of Sago Starch
252 Biomass Recalcitrance 253 Role of Water
30 METHODS AND MATERIALS 31 Materials
3 1 1 Sago Logs
312 Commercial Sago Flour
32 Methods
32 1 Wet Method
322 Dry (Argao) Method 323 Hydrolysis
middot324 Powdered Activated Charcoal
33 Analytical Method
111
Iu
11
111
v
VI
vii
1
2
7 7 7
8 12
13 15 17
18 18 18
18
19 19
19 20 21
21
-
331 Glucose Test 21 332 Iodine Test 22 332 Moisture Content 22
40 RESULTS AND DISCUSSIONS 24
41 Wet Method 24 42 Dry Method 25 43 Comparison of Starch Recovery to Previous Work 26 44 Glucose Recovery 27 45 Color of Hydrolyzed Sago Starch 29
50 CONCLUSIONS AND RECOMENDATITION 32
60 REFERRENCES 33
70 APPENDIX 36
IV
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
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Gen
eral
Pro
cess
ing
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ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
I
Pusat Khidmat MakJumat Akademik VNlVERSm MALAYSIA SARAWAK
I
PKHIDMAT MAKLUMAT AKADEMIK
1111111I11~iffilllllllll 1000246769
Comparison Between Wet And Dry Methods Of Starch Extraction From Fresh Sago Pith
Jenefer James Moinsol 26505
A final project report submitted in partial fulfilment of the requirement for the degree of Bachelor of Science with Honours
(Resource Biotechnology)
Supervisor Professor Dr Kopli Bujang
Department of Molecular Biology Faculty of Resource Science and Technology
University Malaysia Sarawak 2013
DECLARATION
I hereby declare no portion of the work referred in this project has been submitted in support
of an application for another degree qualification of this or any other university or institution
of higher learning
---------~--------------------(Jenefer James Moinsol) Resource Biotechnology Department of Molecular Biology Faculty of Resource Science and Technology University Malaysia Sarawak
ACKNOWLEDGEMENTS
First of all I would like to express my deepest appreciation to God the highest for His
blessing and for granting me the strength to accomplish my final year project A special
thanks and sincere appreciation dedicated to my supervisor Professor Dr Kopli Bujang for
all the advice and support throughout this project Special thanks also dedicated to Assoc
Prof Dr Cirilo for his guidance
Millions thanks dedicated to postgraduate students of the Biochemistry Laboratory Faculty
of Resource Science and Technology especially to Miss Rubena Malfia Kamal and Miss Nur
Jannah for their great support and advice throughout accomplishing this project
Next I would love to deliver my sincere gratitude to my family for their encouragement and
understanding during the development of this project Last but not least my greatest
appreciation to all my course mates and friends for their support and motivation
11
Pusat Kbidmat Maklumat Akademik UNIVERSm MALAYSIA SARAWAK
T ABLE OF CONTENTS
Declaration
Acknowledgement
Table of contents
List of Figures
List of Tables
List of Abbreviation
Abstract
Abstrak
10 INTRODUCTION
20 LITERATURE REVIEW 21 General Introduction of Sago Palm 22 Starch Content
23 Productivity and Production of Sago Starch 24 Conversion of Sago Starch Sugar 25 Hydrolysis of Sago Starch
252 Biomass Recalcitrance 253 Role of Water
30 METHODS AND MATERIALS 31 Materials
3 1 1 Sago Logs
312 Commercial Sago Flour
32 Methods
32 1 Wet Method
322 Dry (Argao) Method 323 Hydrolysis
middot324 Powdered Activated Charcoal
33 Analytical Method
111
Iu
11
111
v
VI
vii
1
2
7 7 7
8 12
13 15 17
18 18 18
18
19 19
19 20 21
21
-
331 Glucose Test 21 332 Iodine Test 22 332 Moisture Content 22
40 RESULTS AND DISCUSSIONS 24
41 Wet Method 24 42 Dry Method 25 43 Comparison of Starch Recovery to Previous Work 26 44 Glucose Recovery 27 45 Color of Hydrolyzed Sago Starch 29
50 CONCLUSIONS AND RECOMENDATITION 32
60 REFERRENCES 33
70 APPENDIX 36
IV
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
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I
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~
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OU
ln
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hi
h
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r
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I
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urc
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ure
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Gen
eral
Pro
cess
ing
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ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
DECLARATION
I hereby declare no portion of the work referred in this project has been submitted in support
of an application for another degree qualification of this or any other university or institution
of higher learning
---------~--------------------(Jenefer James Moinsol) Resource Biotechnology Department of Molecular Biology Faculty of Resource Science and Technology University Malaysia Sarawak
ACKNOWLEDGEMENTS
First of all I would like to express my deepest appreciation to God the highest for His
blessing and for granting me the strength to accomplish my final year project A special
thanks and sincere appreciation dedicated to my supervisor Professor Dr Kopli Bujang for
all the advice and support throughout this project Special thanks also dedicated to Assoc
Prof Dr Cirilo for his guidance
Millions thanks dedicated to postgraduate students of the Biochemistry Laboratory Faculty
of Resource Science and Technology especially to Miss Rubena Malfia Kamal and Miss Nur
Jannah for their great support and advice throughout accomplishing this project
Next I would love to deliver my sincere gratitude to my family for their encouragement and
understanding during the development of this project Last but not least my greatest
appreciation to all my course mates and friends for their support and motivation
11
Pusat Kbidmat Maklumat Akademik UNIVERSm MALAYSIA SARAWAK
T ABLE OF CONTENTS
Declaration
Acknowledgement
Table of contents
List of Figures
List of Tables
List of Abbreviation
Abstract
Abstrak
10 INTRODUCTION
20 LITERATURE REVIEW 21 General Introduction of Sago Palm 22 Starch Content
23 Productivity and Production of Sago Starch 24 Conversion of Sago Starch Sugar 25 Hydrolysis of Sago Starch
252 Biomass Recalcitrance 253 Role of Water
30 METHODS AND MATERIALS 31 Materials
3 1 1 Sago Logs
312 Commercial Sago Flour
32 Methods
32 1 Wet Method
322 Dry (Argao) Method 323 Hydrolysis
middot324 Powdered Activated Charcoal
33 Analytical Method
111
Iu
11
111
v
VI
vii
1
2
7 7 7
8 12
13 15 17
18 18 18
18
19 19
19 20 21
21
-
331 Glucose Test 21 332 Iodine Test 22 332 Moisture Content 22
40 RESULTS AND DISCUSSIONS 24
41 Wet Method 24 42 Dry Method 25 43 Comparison of Starch Recovery to Previous Work 26 44 Glucose Recovery 27 45 Color of Hydrolyzed Sago Starch 29
50 CONCLUSIONS AND RECOMENDATITION 32
60 REFERRENCES 33
70 APPENDIX 36
IV
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
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un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
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amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
ACKNOWLEDGEMENTS
First of all I would like to express my deepest appreciation to God the highest for His
blessing and for granting me the strength to accomplish my final year project A special
thanks and sincere appreciation dedicated to my supervisor Professor Dr Kopli Bujang for
all the advice and support throughout this project Special thanks also dedicated to Assoc
Prof Dr Cirilo for his guidance
Millions thanks dedicated to postgraduate students of the Biochemistry Laboratory Faculty
of Resource Science and Technology especially to Miss Rubena Malfia Kamal and Miss Nur
Jannah for their great support and advice throughout accomplishing this project
Next I would love to deliver my sincere gratitude to my family for their encouragement and
understanding during the development of this project Last but not least my greatest
appreciation to all my course mates and friends for their support and motivation
11
Pusat Kbidmat Maklumat Akademik UNIVERSm MALAYSIA SARAWAK
T ABLE OF CONTENTS
Declaration
Acknowledgement
Table of contents
List of Figures
List of Tables
List of Abbreviation
Abstract
Abstrak
10 INTRODUCTION
20 LITERATURE REVIEW 21 General Introduction of Sago Palm 22 Starch Content
23 Productivity and Production of Sago Starch 24 Conversion of Sago Starch Sugar 25 Hydrolysis of Sago Starch
252 Biomass Recalcitrance 253 Role of Water
30 METHODS AND MATERIALS 31 Materials
3 1 1 Sago Logs
312 Commercial Sago Flour
32 Methods
32 1 Wet Method
322 Dry (Argao) Method 323 Hydrolysis
middot324 Powdered Activated Charcoal
33 Analytical Method
111
Iu
11
111
v
VI
vii
1
2
7 7 7
8 12
13 15 17
18 18 18
18
19 19
19 20 21
21
-
331 Glucose Test 21 332 Iodine Test 22 332 Moisture Content 22
40 RESULTS AND DISCUSSIONS 24
41 Wet Method 24 42 Dry Method 25 43 Comparison of Starch Recovery to Previous Work 26 44 Glucose Recovery 27 45 Color of Hydrolyzed Sago Starch 29
50 CONCLUSIONS AND RECOMENDATITION 32
60 REFERRENCES 33
70 APPENDIX 36
IV
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
Pusat Kbidmat Maklumat Akademik UNIVERSm MALAYSIA SARAWAK
T ABLE OF CONTENTS
Declaration
Acknowledgement
Table of contents
List of Figures
List of Tables
List of Abbreviation
Abstract
Abstrak
10 INTRODUCTION
20 LITERATURE REVIEW 21 General Introduction of Sago Palm 22 Starch Content
23 Productivity and Production of Sago Starch 24 Conversion of Sago Starch Sugar 25 Hydrolysis of Sago Starch
252 Biomass Recalcitrance 253 Role of Water
30 METHODS AND MATERIALS 31 Materials
3 1 1 Sago Logs
312 Commercial Sago Flour
32 Methods
32 1 Wet Method
322 Dry (Argao) Method 323 Hydrolysis
middot324 Powdered Activated Charcoal
33 Analytical Method
111
Iu
11
111
v
VI
vii
1
2
7 7 7
8 12
13 15 17
18 18 18
18
19 19
19 20 21
21
-
331 Glucose Test 21 332 Iodine Test 22 332 Moisture Content 22
40 RESULTS AND DISCUSSIONS 24
41 Wet Method 24 42 Dry Method 25 43 Comparison of Starch Recovery to Previous Work 26 44 Glucose Recovery 27 45 Color of Hydrolyzed Sago Starch 29
50 CONCLUSIONS AND RECOMENDATITION 32
60 REFERRENCES 33
70 APPENDIX 36
IV
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
331 Glucose Test 21 332 Iodine Test 22 332 Moisture Content 22
40 RESULTS AND DISCUSSIONS 24
41 Wet Method 24 42 Dry Method 25 43 Comparison of Starch Recovery to Previous Work 26 44 Glucose Recovery 27 45 Color of Hydrolyzed Sago Starch 29
50 CONCLUSIONS AND RECOMENDATITION 32
60 REFERRENCES 33
70 APPENDIX 36
IV
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
LIST OF FIGURES
Figure Page
Figure 1 Traditional Processing of Sago Starch 4
Figure 2 General Processing of Sago Starch in Sarawak 5
Figure 3 Application of Sago Palm 9
Figure 4 Manual Debarking of Sago Palm 10
Figure 5 Automated Debarking of Sago Palm 10
Figure 6 Argao Dry Process 12
Figure 7 Simplified representation of cell wall destruction 16
Figure 8 Sago logs 18
Figure 9 Commercial sago flour 18
Figure 10 Dry process 20
Figure 11 Glucose analysis of fresh sago pith and commercial
sago flour 28
Figure 12 Hydrolysed of sago starch 30
Figure 13 Different colour of samples 30
Figure 14 Glucose Standard Curve 36
Figure 15 Starch Standard Curve 36
v
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
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Ii
~I
t
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amp
d
CaE
i VCI~
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Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
LIST OF TABLES
Table Page
Table I Moisture content of sago pith and commercial sago flour 24
Table 2 Starch and glucose recovery in wet method 25
Table 3 Starch content and recovery in dry method 26
Table 4 Result comparison of starch recovery with previous work 27
Table 5 Comparison in Dry Method Wet Method and Commercial Sago Flour 29
Vi
ltt
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
LIST OF ABBREVIATIONS
DNS
DM
g
giL
kg
L
LCDA
m
mL
nm
PAC
PPO
RM
III
V
Dini trosalicylic acid
dry matter
grams
gram per litre
kilogram
Liter
Land Custody and Development Authority
mitre
milliliter
nanometer
Powdered Activated Charcoal
polyphenoloxidase
Ringgit Malaysia
microlitre
volume
Vll
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
Comparison Between Wet and Dry Methods Of Starch Extraction From Fresh Sago
Pith
Jenefer James Moinsol
Resource Biotechnology Programme Faculty of Resource Science and Technology
University Malaysia Sarawak
ABSTRACT
Melroxylon sagu or commonly known as sago palm is the most promising starch-producing crop in Malaysia whereby many products can be derived from its starch in both food and non- food industries worldwide This unique palm which can strive in peat soils with less monitoring needed is reported to be able to produce starch approximately 20 kgllog In this project fresh sago pith samples were obtained from Samarahan whereby it was subjected to starch extraction by dry and commercial wet extraction method The dry process was conducted strictly without the use of water in which the fresh sago pith was sliced into thin pieces oven dried at 60oC grounded and sieved to produce fine sago powder In the wet method the sago filtrate and its residue (sago hampas) were hydrolyzed separately whereby the sago hampas was oven dried at 600C prior to hydrolysis In the hydrolysis of sago starch Termamyl- 120L was used in liquefaction whereas AMGfurther digest the liquid starch in saccharification process The starch content and recovery in the dry method was 2071 giL and 207 whereas in the wet method sago filtrate contain 147 1 giL starch with 147 recovery whereby its residue shows lower starch content of 921 giL with only 92 recovery The glucose recovery for starch from the dry method was 889 whereas from starch in the wet method was 691 in the sago filtrate and 591 in the sago hampas Therefore dry method has proven to be more effective compared to wet extraction in extracting starch from fresh sago pith with higher starch content (2071 giL) and recovery (207) as well as producing high glucose recovery (889)
Keywords dry extraction wet extraction Melroxylon sagu sago starch hydrolysis
A BSTRAK
Melroxvlon sagu alau lebih dikenali sebagai pokok sagu adalah sejenis lumbuhan menghasilkan kanji berpolensi linggi di Malaysia yang boleh menghasilkan pelbagai prodllk dalam induslri makal1an dan bukan makanan sedunia Tumbuhan unik yang boleh hidup di lanah gamblll dan lidak memerlukan penjagaan rapi ini mampu menghasilkan kanji dalam anggaran 20kglbalang Dalam projek ini sampel empulur sagu segar diperoplehi dari Samarahan unluk pengeslrakan kanji menggunakan leknik kering dan leknik basah komersial Teknik pengekslrakan kering lidak menggunakan air empulur dihiris nipis dikeringkan pada suhu 60oC dikisar dan disaring bagi menghasilkan lepung sagu Dalam leknik basah air lapisan sagu dan hampas sagu menjalani proses hidrolisis berlainan yang mana hampas sagu dikeringkan pada suhu 600 C lerlebih dahulu Dalam proses hidrolisis gula Termamyl- 120L digunakan unluk proses pencairan manakala AMG digunakan dalam sakarifikasi Kandungan dan 10lal pemulihan kanji dalam eknik pengekslrakan kering adalah masingshymasing sebanyak 2071 giL dan 207 manakala dalam pengekslrakan basah air lapisan sagu mengandungi kanji sebanyak 1471 giL dengan pemulihan 147 manakala hampas sagu mempunyai kandungan kanji yang lebih rendah 92lg1L dengan hanya 92 pemulihan Pemlilihan glukosa daripada kanji dalam leknik pengekslrakan kering adalah sebanyak 889 manakala pemlllihan glukosa daripada kanji dalam lekik basah adalah sebanyak 691 dalam air lapisan sagu manakala hanya 591 dalam hampas sagu Oleh yang demikian leknik kering lerbukli lebih efekli daripada eknik basah dalam mengekslrak kanji daripada empulur sagu segar dengan kandungan kanji (2071 giL) dan pemulihan kanji (207) yang linggi serla mampu menghasilkan pemulihan glukosa yang linggi (889)
Kala kuncis pengekslrakan kering pel1gekslrakan basah Melroglon ~ kanji sagu hidrolisi
1
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
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Ii
~I
t
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amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
10 INTRODUCTION
Starch is a major source of energy in human diet which contributes 50-70 of total
consumption providing direct source of glucose (Copeland et al 2006) The industrial
starches as classified by Karim et al (2008) generally derived from cereals (com wheat
rice sorghum) tubers (potato sweet potato) roots (cassava) and legumes (mug bean green
pea) Sago starch is the only example of commercial starch that derived from the stem of
palm (sago palm) (Karim et al 2008) in which the global consumption of sago starch lies
between 200 000 to 300 000 tons per annum that accounts 3 of total world market of
starches (Bujang 2010) Rauwerdink as cited by Karim et al (2008) has grouped the 2 most
important starch- producing speciesMetroxylon sagu Rottb and Metroxylon rumphii Mart
into Metroxylon sagu M sagu which is well distributed in Southeast Asia New Guinea and
some islands in Micronesia and Polynesia (Bujang 2010) can be found in tropical lowland
forest and freshwater swamps and able to grow in a variety of soil types
Flach (1997) stated that many efforts have been made to increase the production of sago
palms from some commercial genus available initially in Singapore in 10hor (West
Malaysia) and in Riau Archipelago (Indonesia) Sago palm is also commercially produced in
Sarawak (East Malaysia) in which it is grown mostly on peat soils Based on Stanton as cited
by Flach (1997) the advantages of sago palm are that it is economically acceptable relatively
sustainable environmental friendly uniquely versatile vigorous and encourage socially
stable agroforestry systems
Karim et al (2008) stated that the potential of sago palm in the global starch industry has
led to the establishment of Sarawak estate plantations by the Land Custody and Development
2
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
Authority (LCD A) in 1982 in which the first worlds commercial sago plantation was
developed in Mukah (long 1995)
Both the traditional and commercial production of sago starch has the same principles
and similar methods which differs only in the scale operation The traditional processing of
sago starch is shown in Figure 1 The traditional sago palm processing can be summarized by
the pith is rasped by means of a chopper or small hoe made from bamboo followed by the
addition of water to the rasped mixture of fiber and pith which either kneaded by hand or
trampled by foot and collection of the wet starch (Karim et aI 2008) Generally the sago
palms are selected and felled when about 75-9 m high in which the felling of the palm is
usually calTied out after the flowering but immediately before the fruiting stage (Singhal et
al 2008 Tie 2004) As briefly described by Bujang (2011) sago palm at first need to be
felled and cut into 1 m logs and transported to the sago mill whereby the logs will be auto or
manually debarked to expose the pith The rasping will be followed by hammer milling of the
crushed pith to release starch The crushed pith will be mixed with water to form slurry and
undergo centrifugation to separate starch from the fiberous residue Prior to packaging the
wet starch suspension need to undergo flash- drying (Bujang 2011) The general processing
of sago starch is shown in Figure 2 Being the state with the largest sago plantation area
Sarawak has the upper hand in the production of sago starch- derived products in both food
and non- food industries Sago sugarglucosethat can be used as fermentation substrate is
highly available in which it is produced from the hydrolysis of starch
Karim et al (2008) stated that traditional extraction of sago suffer low productivity rates
(25 -41 )Therefore many research studies have been done to improve the quality of sago
flour which aid the transformation of sago flour processing from traditional technology to
modern technology The different methods of starch extraction gave rise to various quality of
sago starch The well accepted commercial wet process to extract starch requires large
3
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
amount of water for washing in which Bujang ef al (1996) estimated that at least 20 litres of
wastewater is released to the environment for every 1 kg of starch produced Hence the
commercial production of sago starch will eventually cause pollution to the rivers
Figure 1 The Traditional Processing of Sago Starch (A) the pith is rasped by means of a chopper or a small hoe made from bamboo (8) water is added to the rasped mixture of fiber and pith which is
kneaded by hand (or trampled by foot) (C) collection of the wet starch (Karim et al 2008)
4
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
~i 9 3~
lYm
rmtll
V
I
U 00
-= gt811
1 0
0shy
~gt
~~
~i
~~
~
--+
n~
h (
OU
ln
libr
~s
In
lInhco
un~
libr
M W
~~I
hi
h
1I
1l
r
--+
hiil1
I~~
I
lilll
urc
h U
l
ibrf
t
r --+
~
ltvflb
ro
~r
r
--+
COU
1gt
Ii
~I
t
Dry
amp
d
CaE
i VCI~
Dry
Fig
ure
2
Gen
eral
Pro
cess
ing
of S
ago
Sta
rch
In S
araw
ak (
Buj
ang
201
1)
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
Kamal et at (2007) conducted extraction of starch by dry grating the sago pith and followed
by small addition of water in the filtration process This process uses lesser amount of water
compared to the conventional method On the other hand a study conducted by Flores
(2009a) has introduced the Argao Dry Process whereby it eliminates the total use of water
from the entire process of sago flour production (starch) and thus provides an alternative
pathway to reduce the drawback of sago processing which is the high amount of wastewater
at minimum of20 L for every kg starch extracted (Bujang et at 1996)
The aim of this project is to compare between wet and dry extraction process of starch
from fresh sago pith as well as to investigate whether the difference in the extraction methods
affects the yield of starch and sugar
6
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
20 LITERATURE REVIEW
21 General Description of Sago Palm
The true sago palm (Msagu) is a pinnate-leaved palm whereby its scientific name is derived
from metra meaning pith or parenchyma and xylon meaning xylem (Flach 1997) Flach
(1997) describe the palm as soboliferous in which it produces tillers or suckers and it is also
hapaxanthic flowers only once and dies shortly thereafter The development of a huge
branched terminal inflorescence together with a large number of fruits indicates the end of its
life cycle The production of flowers and fruits utilize the stored starch in the bole in which
after the fruits formed the trunk decays and one or more of the suckers from the clusters
takes over (Flach 1997)
An overview of literature and some research on seed germination has been done by
Jong (1995) The seed will only germinate when fully ripen which is manifested by a strawshy
colored husk and a large fruit size The seeds start to germinate immediately when stored in a
moist environment and quickly
However the seeds germination
loosening of the operculum
lose
can
their
further
viability when
be induced by
stored
the re
under
moval
dry
of th
conditions
e husk and
22 Starch Content
Research on the distribution and variation in the starch and moisture content of sago palm has
been done by long (1995) and revealed that increasing maturity of the sago palm up to
flowering stage is proportional to the average content and density of dry starch Prior to the
emergence of inflorescence structure maximum starch content of 18-20 is found between
the full trunk growth stage and flowering stage Thereafter the starch content drastically
reduced to about 4-6 long (1995) also found that moisture content decline as the palm
7
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
mature especially in the lower part of the palm The highest starch content of the trunk
corresponds to the lowest mean moisture content of the palm from the complete trunk growth
stage to flowering stage whereby the mean moisture constant is higher in young and overshy
mature palms The density of trunk is constant along the whole trunk length in each growth
stage in which it reaches the maximum between the complete trunk growth and flowering
stage followed by a sharp decrease at over-mature stage Therefore Jong (1995) claimed that
the pattern of starch accumulation corresponds to the density of the trunk and the starch
content in it Thus it enables the palm to be harvested at the COlTect growth stage with
maximum starch yield and aid the grading of sago logs for its starch yield based on their
buoyancy
23 Productivity and Production of Sago Starch
Despite the fact that sago palm is a minor cash crop in Malaysia which occupies less than 1
of total land use (Flores 2009b) sago palm with an average weight of 130 kg for each log
(Bujang amp Ahmad 2000) is the most versatile cash- crop starch- producing plant in Malaysia
which have a wide extensive applications that can be summarized in Figure 3 The usage of
native sago starch is limited as in food ingredients high fructose syrup glucose and edible
film lemantak (Bujang amp Ahmad 2000 Karim et al 2008 Singhal et al 2008) However
the modified sago starch with more stability and gel strength is widely used in many
applications such as an absorbent starch gel in ice packs and fragrance gels (Flores 2009b
Singhal et af 2008) Described as green by Flores (2009b) for its various uses in both
native and modified starch the advancement of biotechnology brought sago starch further
into the conversion of high value product such as ethanol for fuel acetic acid and lactic acid
which have high price value in the biopolymer industries (Bujang amp Ahmad 2000 Bujang et
al 2001 Bujang 2008 Flores 2009b Karim et al 2008)
8
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
pith --+ rasped ampdried
thatching
house building
ethanol oxldlsed starches
as animal feed
dlaldehyde ethers amp starch II esters
------r~--~
food industry
fuel ampother pharmaceutical
Industrial us lleatlons
Figure 3 Applications of Sago Palm (adapted from Flach 1983 wwwipgricgiarorg)
Commercial sago flour (starch) in Malaysia is produced mainly in Sarawak which is
also the biggest sago exporters in the world (Booty amp Bujang 2009 Kamal et aI 2007) that
integrates a fully mechanical process to isolate starch in its modem factories Most of the
mills in Sarawak is still debarking the logs manually as shown in Figure 4 though it is labour
intensive as the bark with the right thickness can be removed more accurately compared to
automated machine The automated debarking of sago palm is shown in Figure 5 Bujang
and Ahmad (2000) reported that 12 tons of starch which is equivalent to 20 kg of starchlog is
produced daily whereby it is also stated that the soil condition and soil spacing in the
plantation affects the starch yields (Bujang amp Ahmad 2000 long 1995) Therefore more
efforts need to be undertaken to improve and maximize the starch production including the
9
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
use of enzymes installment of high-tech equipments and improvement of the well accepted
wet process starch extraction method
Figure 4 Manual Debarking of Sago Palm (Bujang 2011)
Figure 5 Automated Debarking of Sago Palm (Bujang 2011)
Ineffective extraction process reduce production yield as it directly proportional on
the methods applied in which Karim el al (2008) claim that the mechanical process currently
used to extract sago starch is ineffective in which it still unable to dislodge remaining starch
embedded in the fibrous portion of sago pith whereby based on Vikineswary el al (as cited
by Kamal el al 2007) up to 60 of starch still remains in the residue In the study conducted
by Kamal el al (2007) two techniques were used to extract the sago starch from 1 kg raw
10
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
sago The first technique was blending with sufficient amount of water to form slurry and was
filtered and squeezed manually On the other hand the second technique undergoes
mechanical dry grating and squeezing in which small amount of water was added during the
squeezing process The first technique resulted in 26 yield that was 25764 g of sago flour
whereby the second technique yielded only 13 recovery of starch that was 1348 g sago
flour produced from 1 kg raw sago
The Argao Dry Process as reported by Flores (2009a) was a strictly dry process
primarily for food and its subsequent industrial applications Compared to the method used
by Kamal et al (2007) Argao Dry Process does not require addition of water throughout
the whole process of producing sago flour (starch)
Figure 6 shows the Argao Dry Process The sago bole used was cut into thin slices
and left to be sun dried before being pulverized and sieved to the desired mesh sizes and
repounding the coarse residue to obtain desired powder fitness In this study 3 grades of sago
flour was obtained 60 mesh 100 mesh and 200 mesh fines whereby starch purity decrease
with the coarser grade as total fibre polyphenol content and antioxidant activity are the
highest (Flores 2009a)
II
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
A
B
c
Figure 6 Argao Dry Process (A) preparing of the sago logs (B) strippingdrying (C) pulverizing by mortar and pestle (D) sieving the powder (adapted from Flores 2009a courtesy of
UPMindanao Food Museum Collection)
12
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
24 Conversion of Sago Starch Sugar
Sago palm produce high yield of starch for the production of biofuel and bioplastic Based on
Ehara (2012) study the trunk of the sago palm has a starch storage capacity of approximately
300kg by dry weight with large variant in the starch yield The starch yield can be determined
from the weight of the dry matter (DM) and starch content of the pith by spectrophotometer
reading and glucose analysis (Ehara 2012)
Bujang et at (2001) stated that approximately 20 000 ha of sago planting area found
in Sarawak in which a ton of glucose can be converted to 500 kg of ethanol and as such 1000
ha of sago plantation will be able to produce 12 500 tons of biofuel Therefore the use of
sago starch which is highly available resolves the fuel issues in which the starch at first need
to be hydrolyzed into glucose prior being a substrate in the fermentation process Thus many
studies have been done to improve the productivity of the fermentation process which
involves the optimization of pH temperature and enzyme used
According to Ito et al (as cited by Singhal et at 2008) sago starch contains 27
amylose and 73 amylopectin whereby the amylose content of the starch from the lower part
of the trunk is higher than that from the upper part of the trunk According to Uthumporn et
at (2009) the amylose and amylopectin in starch granule are densely packed in a
semicrystalline state with inter- and intra-molecular bonds and proven that sago starch has
high resistance towards degradation as its granular structure remained intact and did not
disrupt the water binding capacity
The applications of microbial enzymes m hydrolysis of sago starch enable the
production of sugar that is highly recommended to be used in ethanol production as substrate
(Booty amp Bujang 2009) Furthermore Booty and Bujang (2009) also stated that the
13
~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
fennentation of glucose produces L- lactate which is the basis element in the production of
biodegradable plastic
25 Hydrolysis of Sago Starch
Hydrolysis is chemical decomposition process using water to separate chemical bonds
from its substance in which one or more water molecules split into hydrogen and hydroxide
ions which may participate in further reactions (Purba 2009) The process is influenced by
several factors such as enzyme particle size temperature pH time the ratio between liquid
and substrate as well as agitation (Saraswati as cited in Purba 2009)
The hydrolysis process in sago starch involves two enzymatic steps liquefaction and
saccharification in which according to Haska and Ohta (as cited by Lai 2008) sago starch
required a longer hydrolysis time due to resistance to hydrolysis enzyme In industrial
practice the starch slurry is gelatinized by heat treatment in which the intermolecular bonds
of starch molecules were broken down to loosen the starch granule (Jorgensen et al 2007)
and followed by liquefaction using endo-acting enzyme such as a-amylase (EC 3211) to
hydrolyze internal a-l4-linkages in amylose and amylopectin producing soluble dextrin
(Lai 2008 Rishabha et al 2010) whereby in saccharification step the soluble dextrin
converted to glucose by glucoamylase (Lai 2008) However Awg- Adeniet al (2013) stated
that dextrin maltose and maltotriose were coexists in the hydrolyzed sago syrup (HSS)
instead of glucose as the main component Therefore enzymatic saccharification is a
complex and dynamic process whereby it is difficult to theoretically calculate the yield purely
based on an assumed initial volume and sugar concentration in the aqueous phase (Kristensen
et al 2008b)
14 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~
Glucoamylaseamyloglucosidaseglucogenic enzyme (EC3213) hydrolyses single
glucose units from the non-reducing ends of amylose and amylopectin as well as able to
hydrolyse the I 6-a-linkages at the branching points of amylopectin (Ellaiah et al 2002)
Meagher et al (as cited by Lai 2008) stated that it is an exo-acting enzyme that able
producing P-D-glucose and hydrolyse both a-(l-4) and a-(1-6) glycosidic linkages which
completely convert solubilized starch into D-glucose
In the hydrolysis process cellulose is the main target for the bioconversion as it
contain abundant polymer and made up entirely of fermentable glucose units (Kristensen
2008) According to Govindasamy et af (1991) the gelatinized starch in solution can exist in
individual molecules or several physical forms in which it could be trapped in granule
remnants entangled in gelled masses or as recrystallized (retro-graded) polymers and as a
combination of the above forms The distribution of such forms and consequently the
solubility of the sample are influenced by processing conditions (Jackson et al as cited by
Govindasamy et al 1991)
251 Biomass Recalcitrance
Mandel (as cited by Kristensen 2008a) stated that hydrolysis is possible even at very high
solids concentrations although the rate of reaction may be jeopardise and cause difficulties in
measuring and determining the conversion yield In the hydrolysis reaction where insoluble
biomass is subjected to liquefaction the density and volume of the liquid phase increases
with the decrease of solids level
Biomass recalcitrance refers to the resistance to deconstruction of plant biomass
which form efficient barrier against intrusion and degradation whereby the structural
15 ~