journal of the science of food and agriculture volume 50 issue 1 1990 [doi...

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J Sci Food Agric 1990,50, 1 1 1 1 17

Composition of Clove Syzygium aromaticum) Bud OilExtracted Using Carbon Dioxide

Narayanan Gopalakrishnan, Padmanabha Pillai V Shanti and

Cadavallur Subrahmanian Narayanan

Regional Research Laboratory (CSIR), Trivandrum 695019, India

(Received 16 December 1988; revised version received 1 March 1989;accepted 16 March 1989)

A B S T R A C T

Analysis of clove (Syzygium aromaticum L ) ud oil ex tracte d with liquid and

supercritical carbon dioxide shows significant qualitative and quantitative

compo sitional d@erences compared with oil obtained by the conventional

hydrodistillation process. The parameters of pressure, temperature, contact

time et c, and also the clove oil components, affect the extraction of the bud

flavour ffom the spice.

K e y words: Clove bud, Syzygium aromaticum, car bo n dioxide extraction.

INTRODUCI'ION

Liquid and supercritical carbon dioxide extraction of perfumery and flavouringmaterials ha s been a subject of study an d research in recent years. The reasons for

welcoming this new technique for extraction are many, including the ideal

behaviourof

CO, asa

solvent at high pressure and supercritical and subcriticaltemperatures (Grimmet 1981; Brogle 1982 .CO can be liquefied a t high pressures

by maintaining a temperature below 31°C and at the supercritical state bymaintaining a t one above it (Grimmet 1981; Brogle 1982; Rizvi e t a f 1986 . Manylimitations of the conventional hydrodistillation and solvent extraction of

perfumery and flavouring materials can be overcome by adopting the newtechnique of CO, extraction (Moyler 1986 . A natural a rom a extract without freefrom changes brough t a bo ut by heat an d w ater, solvent residues and other artefactscan be obtained by this method.

The solubility of different organic compounds is influenced significantly by

1 1 1

J Sci Food Agric 0022-5142/89/. 03.50 989 Society of Chem ical Industry. Printed in G reat Britain



112 N Gopalakrishttati. P P V Shariti, C S Nurayanart

pressure, contact time, temperature, co-solvents etc (Stahl and Gerard 1985).

Reports on the solubility of com poun ds in liquid and sup ercritical C O , are few in

number. The solubility of individual compounds in mixtures and in multi-

component systems has not been studied a t all. Such da ta a re very impo rtant for the

extraction of perfumery and flavouring material using CO .

Th e object of this study is to unde rstand the extractability of ma jor flavouring

components of clove buds using liquid a nd supercritical CO, at different pressures,

temperatures, contact times etc, parameters having a direct bearing on the yield,

colour a nd aro m a of clove bud Gil.

EX PER IM EN TA L

Material preparation

The clove Syzygi um aromaticum L ) buds were procured from the local market an dground, and 1OOg was used for each extraction. Volatile oil, moisture and

chlorophyll contents of the extrac ts were determined using AOAC 1980)methods.

Extraction using CO

Extraction equipment

A liquid and supercritical fluid extraction unit manufactured by No va W erke AG,

Effretikon, Sw itzerland, was used for the p resent study (see Fig 1 . Th e equipment

has a 200-ml extractor and a 200-ml sep arato r, and is attached t o a compressor

developing the required range of pressures. Inbuilt arrangements are provided for

heating/cooling both the extractor and separator.

Parameters selected for extraction

Parameters selected for the study of CO extraction of clove buds were pressure,

temperature, contact time, moisture content and the number of consecutiveextractions. The conditions used were: pressures of 100, 250, 4 and 500 bar

(1bar = lo5 P a ) a t 40°C for 30 min contact time; temperature a t 20 and 4 °C at 250

bar keeping a contact time of 30min; mo isture contents at 90 and 180g kg- at

4 °C nd 250 bar an d 30min contact time; repeated extraction a t lOOand 250 bar at

4 °C and 30min contact time for each extraction.

COMPRESS.OR

HEAT1

COOL1

E X RA1‘

HEATING/C O O L I N 6

Fig 1. CO extraction equipment. P Pressure; T=temperature.



Composition of clove (Syzygium arom aticum ) hiid oil e.ctructed using curbon dioxide 113

Extraction procedure

Ground clove (100 g) was placed in the extractor and the required CO, pressure was

generated using the compressor. The temperature for supercritical CO, extraction

was maintained by circulating warm water at 40+l C and that for liquid CO,

extraction was maintained by circulating cold water at 20+ 1°C.After attaining the

pressure the inlet and outlet were closed during the contact time, before releasing

the CO, phase into the separator. When released, the CO was allowed to pass

through the outlet from the separator. The extract was collected from the separator.

Analysis of extracts

The yield of the extract was calculated on a direct weight basis. Analysis of the

volatile oil was carried out using a Hewlett-Packard 5840A model GC nit with a

stainless steel column packed with 30g kg-' OV-17 on Chromosorb WHP (15&

180 Hm).N, at 20 ml min-'

was used as carrier gas. The column was programmedfrom 80 to 220°C at the rate of 5°C min- '.

RESULTS AND DISCUSSION

Yield and composition of distilled oil

The clove buds used for the study were found to contain 181 g kg-' oil by the

standard hydrodistillation method, a higher value than those generally reported

(Muchamad and Crouzet 1980; Purseglove et al 1981). The oil thus obtained was

almost colourless and free from chlorophyll. The major components, eugenol,eugenol acetate and caryophylene, were present at 585, 221 and 141 g kg-' ,

respectively

Effect of CO, pressure on yield and composition of clove extract

The pressure of CO, during extraction, especially in the range 1W250bar (Table

I ) ,was found to have direct bearing on the yield of extract. The extract was greenish

brown in colour and the colour was more intense in the extract obtained at high

pressure. The increased yield was due to the higher diffusivity of supercritical CO,

at the higher pressure (Dandge et a1 1985). Chlorophyll and carotenoids are not

soluble in supercritical CO, (Hyatt 1984) but the components of clove oil play an

important role in dissolving the colouring matter during CO extraction. Even

though the chlorophyll content of the extract increased with pressure, a significant

rise was noted over the range 250-400 bar. The major volatile component of clove

extract, eugenol, increased from 525 to 622 g kg- ',corresponding to a pressure

increase from 100 to 500 bar. Eugenol acetate decreased by 3 g kg-' during the

above pressure increase. Even though a steady change in the content of

caryophylene was not observed, reduction in the content was found at higher

pressure. More significant was the compositional difference between the hydro-

volatiles of clove oil and those extracted with CO,.

Effect of temperature on the yield and composition of clove extract

Liquid CO extraction was carried out at 20°C and supercritical extraction at 40°C,



114 N Gopalakrishnan, P P V Shanti, C S Narayanan

TABLE 1Effect of CO, pressure on yield and composition of clove bud oil (kg-’)

Yield and components Pressure ba r)

100 250 400 500 Distilledoil

Yield, g 68Chlorophyll, mg 1.7

a-Copaene, g 16Caryophylene+humulene, g 199

Eugenol, g 525

Isoeugenol, g 14

a-Cubebene, g 9

Eugenol acetate, g 215

Farnesol, g 12

Temperature 40°C; contact time 30 min.

1501.857

12164563

19200

6

1844.57

12171

6059

196

Trace

187

5.86

13164

62211

185

3

181

5

13145585

1722 1

8

TABLE 2Effect of temperature on yield and composition of clove bud oil kg-’)

Yield and components Temperature “ C )

20 40Liquid C O , ) Supercritical C O , )

Yield, gChlorophyll, mga-Cubebene,ga-Copaene, gCaryophylene+humulene, gEugenol, gIsoeugenol, gEugenol acetate, gFarnesol, g

1-931.736

145650

3

1846

681.79

16199525

14

21512

Pressure 100 bar; contact time 30 min.

both at 100 bar. The temperature variation affects the physical state of CO,. At

higher pressures, C 0 2 is a liquid below 31°C and is in a supercritical fluid state

above 31°C. Remarkable differences in the quantitative and qualitative

composition of the extract were noted under these conditions. Yields were 193 and

68g kg- at liquid and supercritical conditions of extraction, respectively Table 2).

The yield with liquid CO, was more than that by hydrodistillation because of theextraction of higher molecular weight components of the cloves. Higher levels of

caryophylene and eugenol acetate were measured in the liquid CO, extract. The

chlorophyll content was found to be at the same level in both these extracts.



Composition of clove (Syzygium aromaticum)bud oil extracted using carbon dioxide 1 I

TABLE 3Effect ofcontact time on yield and composition ofclove bud oil (kg - I )

Yield and components Contac t time h )

2

Yield, gChlorophyll, mga-Cubebene,ga-Copaene, gCaryophylene+humulene, gEugenol, gIsoeugenol, gEugenol acetate, gFarnesol, g

1501.85

12164563

19200

6

1757.656

13174613

12183

5

1768.4

67

190

6785

114Trace

Pressure 250 bar; temperature 40°C.

Effect of contact time on the yield and composition of extract

Table 3 gives th e effectof change in the contact time a t 250 bar an d 40°Con the yield

an d com position. The yield increased from 150 to 175 g kg- when the contact timeincreased from 30 to 60 min. A further increase did not show a significant effect.Th us th e optimum time required t o extract the oil was 1 h. The chlorophyll content

increased significantly with contact time. A steady increase in the proportion ofcaryophylene and eugenol, and a decrease in eugenol acetate content, were themajor compositional changes when th e contact time w as increased from 30 to 120

min at 40°C and 250 bar. Increase in the yield of extract from 30 to 60 min contact

time was accounted for by the extra eugenol dissolved.

Effect of moisture content on yield and composition of the extract

Th e effect of moisture content in th e extract was examined a t the 90 and 180 g kg-

moisture level in ground buds w hen extracted a t 250 bar, 40°C and 30 min contact

time. T he yield of extract was increased from 150 to 168 g kg- (Table 4), and thechlorophyll content showed a two-fold increase when the moisture contentincreased from 90 to 180g kg- . Eugenol increased from 563 to 610 g kg- andcaryophylene from 164 to 179 g kg - whereas eugenol acetate decreased from 200

to 182 g k g - ' .

Effect of repeated extraction on the yield and composition of extract

Repeated extraction at 100and 250 bar, 40°C an d a contact time of 30 min resultedin an almost identical pattern of change (Table 5 . A better yield was noted in the

first extraction a nd the chlorophyll content was higher in th e second extract a t 250bar than in the first extract. A decrease in the proportion of caryophylene andincreases in eugenol and eugenol acetate were other significant changes notedduring repeated extraction.



116 N Gopalakrishnan, P P V Shanti, C S Nurayanan

TABLE 4Effect ofmoisture co ntent o n yield an d com position ofclove bud oil

(kg- )

Yield and components Moisture content ( )

9 8

Yield, g 150 168Chloro phy ll, mg 1.9 5.2a-Cubebene, g 7 6a-Cop aene, g 12 11

Caryophylene +humulene, g 164 179Eugenol, g 563 610Isoeugenol, g 19 12Eugenol acetate, g 200 182

Farnesol, g 6 Trace

Pressure 250 bar; temperature 40°C; contact time 30 min.

TABLE 5Effect of repeated extraction o n yield a nd composition of clove bud oil (kg- )

Yield and components Pressure and extruction stage

100 bar 250 bur

1 s t 2nd 1st 2nd

Yield, gChlorophyll, mga-Cubebene, ga-Copaene, gCaryophylene +humulene, g

Eugenol, gIsoeugenol, gEugenol acetate, gFarnesol, g

681.79

16199525

14215

12

441.68

13

I72547

14224

13

150 26.9 2.2

7 512 13

164 136563 616

19 12200 202

6 6

Tempeature 40°C; contact time 30 min.

CONCLUSION

Va r ious p a r a m e te r s f o r the e x t ra c t ion of c love bud oil ha ve a s t ro ng influence on t h e

q u a n t i t y a n d q u a l i t y of the produc ts . Eugenol ace ta te , which cont r ibutes to as w ee te r a n d m o r e floral o d o u r , w a s m o r e a b u n d a n t i n t h e p r o d u c t o b t ai n e d a t l ow e r

p r e ssu r es a n d shor t e r c on ta c t t im e . Th e colour of t h e oil was less in tense under thesec o n d it io n s , d u e to reduced ext rac t ion of c h lo r ophy l l. T he p r e se nc e of sm a l l a m oun t s

of non-vola t ile mate r ia ls m ay a lso p lay an im p or t a n t r o l e in the be t te r f la vour o f the

c love bud ext rac t .



Composition of clove (Syzygium aromaticum bud oi l extracted using carbon d iox ide 117

S e nsor y a sse ssm e n t o f the p r o duc t ob ta ine d by l iqu id c a r b on d io x ide ex t r a c tion ,

a n d also t h a t o b t a i n e d a t 100 b a r a n d 4@C, s h o w e d t h a t t h e oils were sw ee te r and

m o r e f lo r al t h a n the distilled oil.

T hu s , the d i f ferent par am ete r s s tudied , co m bin ed wi th th e co-solvent e ffec t of

each of the c o m p o n e n t s in t he e x t r a c t, are im por t a n t f a c to r s in d e t e rm i n i n g t h e

qua l i ty of c l ov e b u d flavour.

REFERENCES

AOAC 1980 OfJicial Methods of Analysis (12th edn). A ssociation of A nalytical Chem ists,

Brogle H 1982 Ca rbo n dioxide in solvent extraction Chem nd 385-390.Dandge D K, Heller J P, Wilson K V 1985 Structure solubility correlation: organic

compounds and dense carbon dioxide binary systems. Ind Eng Chem Prod Res Dev 24

Grim met C 1981 The use of liquid carbon dioxide for extracting natural products. Chem Ind

359-362.Hyatt J A 1984 Liquid an d supercritical carbon dioxide as organic solvent. J Org Chem 49

5097.Moyler D A 1986 Liquid carbon dioxide extraction of flavour materials. In : Developments in

Food Flavours, eds Birch G G Lindley M G. Elsevier Applied Science, London,

Muchamad M , Crouzet J 1980 Composition of clove bud oils from different origin. In: Proc

Purseglove J W , Brown E G , Green C L, Robbins S R J 1981 Cloves. In: Spices, Vol I, eds

Rizvi S S H, Daniels J A, Benando A L, Zallweg J A 1986 Supercritical fluid extraction:

Stahl E, Gerard D 1985 Solub ility behav iour and frac tionation of essential oils in dense

Washington, DC.

162- 168.

pp 119-129.

8t h Int Congr Essential Oils C a n n a , pp 255-258.

Rhind D Wrigley G . Longm an, Lon don, pp 229-285.

operating principles and food applications. Food Techno140 57-64.

carbon dioxide. Perf Flav 10 29-37.

journal of the science of food and agriculture volume 50 issue 1 1990 [doi...

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