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EXTRACTION AND CHARACTERIZATION OF
WATERMELON SEED OIL
By
UGWUANYI DAVID EJIKE
(2006/24248EH)
DEPARTMENT OF CHEMICAL ENGINEERING
FEDERAL UNIVERSITY OF TECHNOLOGY, MINNA
NIGERIA
November, 2011
EXTRACTION AND CHARACTERIZATION OF
WATERMELON SEED OIL
By
UGWUANYI DAVID EJIKE
(2006/2424SEH)
A PROJECT SUBMITTED TO THE
DEPARTMENT OF CHEMICAL ENGINEERING,
FEDERAL UNIVERSITY OF TECHNOLOGY, MINNA
NIGERIA
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IN PARTIAL .FULFILMENT OF THE REQUmEMENT FOR THE AWARD OF . ,
BACHELOR OF ENGINEERING (B. ENG) DEGREE IN CHEMICAL
ENGINEERING
NOVEMBER, 2011
DECLARATION
I declare that the work in the project report (thesis) entitled EXTRACTION AND
CHARACTERIZATION OF WATERMELON SEED OIL has been performed (carried out) by
me under the supervision of Dr. lO. Okafor. No part ofthis project report (thesis) was presented
for another degree or diploma elsewhere at any institution to the best of my knowledge.
UGWUANYI DAVID EJIKE Date·
Name of Student Signature
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CERTIFICATION
This project titled "Extraction and Characterization of Watermelon Seed Oil" by UGWUANYI
DAVID EJIKE meets the regulations governing the award of, the degree of Bachelor of
Engineering (B. ENG.) of the Federal University of Technology, Minna, and it is approved for
its contribution to scientific knowledge and literary presentation.
Dr. 1. O. Okafor Date
Supervisor
Dr. M.O. Edoga Date
Head of Department
~~Ob(2-01 ~ External Examiner Date ..------ .
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ACKNOWLEDGEMENT
All thanks to Almighty God who kept me alive up to this point, empowering me with the much
needed wisdom, understanding and knowledge needed for the completion of the work.
My heartfelt appreCiation goes to Dr. J.O. Okafor who professionally supervised this project
work. I humbly appreciate his fatherly advice, the love and affection towards me. I appreci~te the .c'~" "\ ~
efforts of the hard working Lecturers of the Chemical Engineering Department especially Dr.
M.O. Edoga (HOD), to mention but a few who.P.ave in one way affected my life for the better of
it. I appreciate the effort of Mr. Bulus (W AFT Lab) who took it upon himself to assist me in all
the analysis carried out in this research work.
My profound gratitude goes to my beloved mother Mrs. Ugwuanyi Elizabeth and my wonderful
sisters Ogochukwu and her husband Phat Ojikeya, Nkechi and Ogochukwu Okanyi for their ,
prayers, affection and financial support throughout my years of studies. I am also grateful to my
aunty and her husband Mr and Mrs Ndubuisi Nnadi and Mr and Mrs Stanley for their immense
support and contributions during my study at the University. I am also grateful to the entire
Omeje family Mrs. Augusta, Mr and Mrs Augustine, Rv. Fr. Chibundu, Mrs Pauline, Associate
Prof. Joachim and his wife Mrs Pet, Dr. Jude and his wife Mrs. Chioma, Mr and Mrs luke and
Mr Chinedu for their moral support, prayers and attention when I needed them most.
Finally, this work will not be complete without giving appreciation to my wonderful uncle and
his wife Mr and Mrs.'Iyke Ugwuanyi and my lovely friends Samuel Erasmus, C~risty Onourah,
and my spiritual father Pastor Erasmus Uruawuike (Late).
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ABSTRACT
The research titled extraction and characterization of watermelon seed oil was carried to
investigate the effect that different drying methods, solvents and seed size wQuld have on the-
quality and quantity of oil from watermelon (Citrilus lanatus) seeds. Tbe watermelon seeds were
removed from the pod and washed. The sample was weighed and divided into two equal parts;
one part was subjected to sun drying while the other part was .subjected to oven drying (at a
temperature of 30°C). Drying by sun as expected was gradual as compared to the Qven drying
method which was faster and more rapid. The dried seeds (sun-dried or oven ... dried) were de-
husked, dry-milled into fine crumbs using hand milling machine. The powdered product from the
mill was then subjected to oil extraction using hexane and petroleum ether as solvent. Proximate
and physico-chemical analysis of water melon seeds were carried out. The results showed that
the seeds contained 5.15 ± 0.03 % moisture, 4.90 ± 0.14 % ash, 50.48 ± 0.05 % fat,
32.38 ± 0.02 % protein, 6.10 ± 0.02 % crude fibre and 6.35 :i: 0.12 % nitrogen free extract.
Physico-chemical characteristics showed that the pale yellow oil had a specific gravity of
.0.860 ± 0.003 and a refractive index of l.47l. Saponification value was 184.29 - 187.09
mgKOHlg (for both drying methods). Iodine value was 103.04 - 115.12 mgIodine/g (for both
dryillS methods). Acid value was 10.4 - 12.8 mgKOHfg and free fatty acid was 5.2 - 6.4
mgKOHIg (for both drying methods). The peroxide value was 18.74 meq peroxide/g. The water ,
-mdon seed can thus be considered a good source of protein with high nutritional value. Many of
~ physieochemical -properties of the seed oil studied .compared favourably with" other
_~~ se-ed ~Us such as soyabean, cowpea, groundnut etc. The watermelon seed oil
_ dt~b_1l$ potcentiai for use as domestic and industrial oil.
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TABLE OF CONTENTS
Pages Content
1
Title Page "
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Declaration III
Certification IV
Acknowledgement V
Abstract ','
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. Table of Content Xl
List of Tables xu
List of F!gures . CHAPTER ONE ,
1 , ."i
1.0 INTRODUCTION .~
2 1.1 Aims and Objectives .'
3 " " ,1.2 Scope of the Study
3 1.3 Problem Statement
4 .'i'
1.4Justification of the Study .~ \
CHAPTER TWO . 5
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,2.0 LITERATURE REVIEW
2.1 Watermelon Seed Background 5
6 2.2 Oil j:
6 < ~- ~ ~
2.2. I fany Aeids 6
2.2.2 Tooopherots 7
1.2.3 Oxidative Stability 7
2.2.4 Refining 9
2.2.4.1 Degumming
10 2.2.4.2 Caustic Neutralization
10 2.2.4.3 Bleaching
11 2.2.4.4 Deodorization Process
, 2.3 Nutritional Benefits of Watermelon Seed Oil 12
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Content
2.3.1 Application of Watermelon Seed Oil
2.3.2 Health Benefits of Watermelon
2.4 Leaching
2.4.1 Methods of Extraction
2.4.1.1 Supercritical Fluid Extraction
, 2.4, 1.2 Solvent Extraction
2.4.1.3 Mechanical Pressing Extraction
2.4.2 Factors Influencing the Rate of Extraction
2.4,2.1 Particle Size
2.4.2.2 Solvent
2.4.2.3 Temperature
2.4,2.4 Agitation of Fluid
2.4.3 Choice of Solvent
, 2.4.3.1 Selectivity
2.4.3.2 Recoverability
.2.4.3.3 ~olatility
2.4.3.4 Purity
2.4.3.S Solubility
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'.$ Pk:,~~Cllemical Properties of Oil
, ~SJ Ad' V:ttJue (free Fatty Acid)
~.$.~ $~,tmifi~Qn Value
l.$'..' i_~,' V~Ju"
2.5.5 Refractive Index
2,5.6 Specific Gravity
2,5,7 Viscosity
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2.6 Proximate Analysis of Oil Bearing Seeds 22 .~ .' . ,
2.6.1 Moisture Content 22
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, 2.6.2 Crude Fiber 23
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2.6.3 Ash Content 23 .r·;'
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2.6.4 Nitrogen Free Extract 24
2.6.5 Crude Protein 24
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2.6.6 Oil Content ,1.,
CHAPTER THREE
3.0 MATERIALS AND METHOD 26
3.1 Sample Preparation Analysis 26
3.1.1 Crushing and Grinding 26
3.1.2 Sieving 26
, 3.1.3 Drying 26
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3.1.4 Materials and Apparatus 27
27 3.1.5 Reagents
3.2 Proximate Analysis ' .. 28
3.2.1 Oil Content 28
. ~, .. 3.2.2 Moisture Content
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3.2.3 Crude Fiber 29
3.2.4 Ash Content '." 30
·3.2.5 Nitrogen Free Extract 31
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3.2.6 Crude Protein 32 ' ].:.
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,3.3 Physico - Chemical Properties of Watermelon Seed Oil 32 :!,
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3.3.1 pH 32 '!
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3.3.2 Refractive Index 32
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3.3.3 Viscosity 32
3.3.4 Specific Gravity 33
3.3.5 Acid Value (Free Fatty Acids) . 33
Pages
Content 34
3.3.6 Saponification Value 34 j .
3.3.7 Peroxide Value 35 "
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3.3.8 Ester Value 3S
3.3.9 Iodine Value ' ('
CHAPTER FOUR 37
4.0 RESULTS AND DISCUSSION 37 ;
4.1 Results ',.
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4.2 Discussion of Results
CHAPTER FIVE 47
5.0 Conclusion and Recommendation _.47
5.1 Conclusion 48
5.2 Recommendation : .
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REFERENCES 57 "
APPENDICES " ~'.
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LISTS OF TABLES
Table
Table 4.1 proximate Composition of Watermelon Seed
Table 4.2 Physico _ Chemical properties of Watermelon Seed Oil (Hexane)
Table 4.3 Physico _ Chemical properties of Watermelon Seed Oil (petroleum ether)
Table A1 Oil extracts'using 0.5 mm sample size (petroleum ether solvent)
Table A2 Oil extracts using 1.0 mm sample size (petroleum ether solvent)
Table A3 Oil extracts using 2.0 mm sample size (petroleum ether solvent)
Table A4 Oil extracts using 0.5 mm sample size (hexane solvent)
Table AS Oil extracts using 1.0 mm sample size (hexane solvent)
Table A6 Oil extracts using 2.0 mm sample size (hexane solvent)
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