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UNIVERSITI PUTRA MALAYSIA CHARACTERISTICS OF MALAYSIAN AND SULAWESIAN COCOA BEANS AND THE OPTIMISATION OF QUALITY THROUGH BLENDING LEOW MIN MIN FSMB 1999 11
UNIVERSITI PUTRA MALAYSIA
CHARACTERISTICS OF MALAYSIAN AND SULAWESIAN COCOA BEANS AND THE OPTIMISATION OF QUALITY THROUGH
BLENDING
LEOW MIN MIN
FSMB 1999 11
CHARACTERISTICS OF MALAYSIAN AND SUlAWESIAN COCOA BEANS AND THE OPTIMISATION OF QUALITY THROUGH
BLENDING
By
LEOW MIN MIN
Thesis Submitted in Fulfilment of the Requirements for the Degree of Master of Science in the Faculty of Food Science and Biotechnology
University Putra Malaysia
August 1999
ACKNOWLEDGEMENT
First of all, the author would like to express her utmost thanks and
gratitude to her parents and sister for their constant encouragement in difficult
times throughout the years.
The author would like to take this opportunity to express her endless
appreciation and gratitude to the chairman of her Supervisory Committee, Prof.
Dr. Jinap Selamat for her guidance, suggestions and most of all patience
throughout the project She is also very grateful to the other member of the
supervisory committee Dr. Azizah Hamid, Assoc. Prof. Dr. Idris and Dr. Chong
Chiew Let (PORIM) for their constructive comments towards the preparation of
this thesis.
Special thanks are conveyed to the members of the cocoa group, Wan,
Amin, Mansoor and Norma for their moral encouragement, time and effort in
helping her throughout the project Sincere appreciation is also extended to all
the staff of the Chemistry and Processing Laboratory especially Mr. Rocky Tan,
Mr. Chan Tin Wan, Mr. Halim Abdul Rahman, Mr. Azman, Ms Siti Shahrul and
Ms Siti Ziryani.
ii
Thanks are also due to the members of the sensory group, Bleinham
Estate (perak), Hasfarm (Sulawesi), Pak Teguh (Indonesia) and Dr. Lai Oi Ming
for their valuable help and moral support.
Last but not least, the author will be ever grateful to her friend Loke C.F.
for all the encouragement, support and patience throughout the whole project
iii
TABLE OF CONTENTS
Page
ACKN'OWLE'DGEMENT ....................................................................... .
. LID OF TABLES ..................•...................................................................
A 'BSf'RA cr .................................................................................................................. .
A'BSf'RAK. •................................................................................................
CHAPTER
1 GENERAL INTRODUCflON ...................................... .
Background .......... . ............................ ........... . . . . . . . . . . . . . . . . . . . . .
Significance of this Study ........................... . . . . . . . . ..
2 LITERATURE REVIEW ...................................................... .
In.uoduction ............................................ .................... . .. . . . . . . . .
Harvesting ................................................... . . . . . . . . . . . . . . . . . . . . . .... .
Ferm.ent:a.tion ....... .. ............ . ......................................... . . . . . ..... .
Ov'erferm.ent:�:tion ................. � .................................... .
Under-ferm.enmtion .......... ........... .................... . . . . . . . . . .
Term.ination of Ferm.entation ..... .... . . . . . . . . . . . . . . . . . . . . ...... .. Drying .. . . . .. . . . . . . . . . . ................................................. . . . . . . . . . . ........ .
Physical Characteristics . . .. .. ......................................... . ........ . Colour ... . . . . . ....................................... . . . . . . . . . . . . . . . . . . . . . .. . . .
Fat Content . .............. . ....................... . . . . . . . . . . . . . . . . . . . ...... .
Melting Point ......................................... . . . . . . . . . . . . . . . . . ... .
Flavour ... . . .. .. ................... .. . . ........... ................. . . . . ....... . Physical Defect:s .. ........................................... . . . . . . . . . . . . . . . .. . . . . . . .
Mouldy Beans ••••••.•.•••..•.••.••••.•.•..•.....•....•.........•..........
Ins.ect Damaged Beans ........ ........ .... . . . . . . . . . . . . . . . . . . . . . . . . . . . Germ.ina ted Beans . ............................. . . . . . . . . . . . . . . . . .. . . . . . .
Sla t:}r Beans . .. .. . . .. .. ........................... . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chemical Characteristics .... ......................... . . . . . . . . . . . . . . . . . . . . ...... .
Acid ............................................................................. .
Polyphenol and Alkaloids ................................ . . . ..... ..
iv
ii viii xi xiii
1
1 6
8
8 8
10 12 13 14 14 15 15 16 17 18 19 20 20 21 21 23 25 29
3
4
Triglycerides .............................. ......... ......................... 32 Solid Fat Content ......................................................... 33
Cocoa Flavour .............................. . . . . . . . . . . .. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 33 Quality of Cocoa Beans ........................................................... 34
GENERAL ANALYSIS METHODS ..................................... 36
Physical Analysis ....................................... ............................. .
Cut Test ........................................................................ .
Fermenmtion Index ..................................................... . Fat Conrent .................................................................. .
Melting Points ..................... ................................. .. ..... .
Solid Fat Con'tent ........................................................ .
Chemical Analysis .................................................................. .
pH Determination ....................................................... .
Tit:I-a"ta.ble acidity ......................................................... .
Non-volatil.e acid .................................. ............. .......... .
Vola tile acid ...................... ........................................... .
Polyphenol and Alkaloids .......................................... .
Saponification Value ............................................. ...... .
Triglyceride .................................................................. .
Fatty Acid Methyl Ester . .. ........................................... .
Statistical Analysis ........... ...................... ................................ .
QUALITY OF COMMERCIAL COCOA BEANS FROM
36 36 36 37 38 39 41 41 42 42 44 45 46. 47 47 48
MALAYSIA AND SULAWESI ................................... ........... 49
Inrroduction .............................................................................. 49 Ma terials and Metltods .. ....... ... ........... ......... ..... ... ...... .............. 51
Samples .......................... ................................................ 51 Analysis ......................... .... . .. ............ ..................... ........ 51
Results and Discussions ......... ............................ ...................... 52 Physical Properties of Commercial Malaysia and Sulawesi Cocoa Beans .................................... ... . . . . . . . . . . . . .. . . ............. . . . . .. .... 52
Cut Test ......................................................................... 52 Fermenta.ti.on fudex ...................................................... .54 Fat Content .•.................................................................. .54 Melting Point ............................ . . ........ .......................... 56
v
Chemical Properties of Commercial Cocoa beans from Malaysia and Sulawesi................. . .. . . . .. ... . . . . . . . . ........... ............... 57
pH and Titratable Acidity ........... ......... .. . . .................... 57 Volatile and Non-volatile Acid ..... . ......... ... . ............... .. 58 Polyphenol and Alkaloids .......... ....................... ..... ... . .. 62 Triglyceride .......... . .. .......... . . . . . . . . . . . . . . . . . . ..... . . . . . . . . . . . . . . . . . . . . . . 65 Fatty Acid .... ....... ........ . ............................... . . ............ ...... 67 Solid Fat Content ............ . . . . ....... . . . .. .... . . . . . . . . . . . . . . . .. . . . . . . . . . . 68
Conclusion . . .............. ....... . ............ ..... . . . .... ....................... ... . . .. .. . . 70
5 EFFECT OF DIFFERENT FERMENTATION LEVEL ON MAlAYSIAN AND SUlAWESIAN COCOA BEANS...... 71
In:uoduction ...... .............................. ............... . ..................... . .. .. 71 Objectives ... ........ .................. . . . . . . . . ... . . . . ... . . . ........ ....... . . . .. . ... . . . . . . . . . 73 Materials and Metltods . ......... . .. . . . . . . . .. .. . .. . . . .. .. . . .. . .. ... . . ..... . . . . . . . . . 73 Effect of Fermentation Level on Physical Characteristics of Cocoa Beans..................................................................................................................................... 74
Bean Defec1:s .................................................................................................................................... 74 Colour of tlte Cotyledon .......... . . .............. ....... ... .......... 76 Fermentation In.dex .............. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Fat Content ......... ....... .. .. . . . . . . ........... . ......... .................... . 80 Melting Temperature ... . . . .... .............................. . . . ........ . 82
Chemical Characteristics of Cocoa Beans witlt Different Fermentation Levels ... ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
pH and Titratable Acidity . ............. . .. ................ . .. ....... 83 Non-Volatile Acid ................................................... ... . . 86 Volatile Acid ....... . ....... .. . . . . . ................ . .... . .. ................... 89 Polyphenol and Alkaloids .... .............. . . . . ......... ......... ... 91 Saponification Value ....... . . ... . . .. . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Triglyceride ................. .. . . . . ... ............... .. .. . ......... . .......... 95 Fatty Acid Metltyl Ester.... ........................................... % Solid Fat Content .... . ..... .. . . . . . . . ................... ...... ......... .. .... . 98
Sensory Evaluation of Cocoa Beans from Different Fermenmtion Levels ..... ......... ....... .... ....... ........ ........................ 99 Conclusion ........................ ........ . . . .... ........ . . . . . . . . . . . . . . . . . . . . . ..... ... . . 102
vi
6
7
QUALITY OF BLENDED COCOA BEANS ...................... . 105
In.ttoduction ..... .... ...... .... ................... ............ ..................... ..... 105 Mal:erials and Metllods .......................................................... 107
Blending .......... ............................................................. 107 Sensory Evaluation .................................................................. 110 Reswts and Discussions ..... ... ... ........ ..... .... ............... ......... ... ... 111 Physical Characteristics of Malaysian and Sulawesian Cocoa Blends ...••...•.•.. ..... .....•...... ................. ...•...... .... .... ..... ..... 111
Fe.rm.enmtion hldex ......................................•..... ......... 111 Fat Cont:e-nt ..•.......•..........................•............................. 113 Polymorphism ............................................................. 116 Melting Temperatttre .................................................. 120 Solid Fat Con'tent ......................................................... 123
Chemical Characteristics of Malaysian and Sulawesian Cocoa Blends .. .•..•...... ..... ...•.. ....... ....... ......... ... ............... .... ...... 125
Acidity of Malaysian and Sulawesian Cocoa Blends .. 125 Non-Volatile Acid of Malaysian and Sulawesian Cocoa Blends .. ....... ...... ...................... .......... ................. 127 Vola"tileAcid................................................................... 131
�nsory Evaluation .................................................................. 133 Cocoa Flavour ............................................................... 133 Bit:ter .............................................................................. 134 So-ur •••••••••••••••••••••••••••••••••••••••••••••••••••••.•••••••••••••••••••••••••• 136 ,Astringent ..................... ..................... ,. ........................... 138 N u'tty' .•....••...... •..•. ..•..• .•. ..•. ..•. ... ..••. •..... .... .•••....•..... ....... ... 139 Green ............................... .............................................. 139
Conclusion ......................................................................... ........ 142
GENERAL CONCLUSION AND RECOMMENDATION 144
BIBLIOGRAPHY ................................................................................... ........ 148 APPENDICES................................................................................................. 156 VIT A................................................................................................................. 165
vii
Table
1
2
3
LIST OF TABLES
Page
Composition of Fresh Cocoa Pulp .......................................... 24
Composition of Fresh Cocoa Nibs .......................................... 25
Range of Acidity and Concentration of Organic Acids from Different Regi.ons .. """"" .... """"" .... ,,"",, .. ,,",, ..... "" .... ,,"" ... " .. " .... " .. ,,"" 27
4 Bean Defects, Colour and Fermentation Index of Commercial Malaysian and Sulawesian Cocoa Beans........ 53
5 Fat Content of Malaysian, Sulawesian and Cocoa Beans of Different Genotypes............................. ............................... 55
6 Melting Point of Malaysian and Sulawesian Cocoa Butter.. 56
7 pH, Titratable Acidity and Organic Acids in Malaysian and Sulawesian Cocoa Beans ................................... ...................... 60
8 Polyphenol and Alkaloids in Malaysian and Sulawesian Cocoa Beans "" .... " .... "" .. """ .. """" .. " .. """" .. ,,,, .. ,,"",, .. ,,""" ...... "" ....... "" .. ,,"""""""" M
9 Triglyceride and Fatty Acid in Malaysia and Sulawesi Cocoa Beans . . "" .. """"" . . """""""""" .. ,,,, .. ,,""""""""""" ... ,,"""""" . . . . ,," . . . """" . . . . ,, . . . . ,,""" 66
10 Solid Fat Content of Malaysian and Sulawesi an Cocoa Butter ........................................................................................ 69
11 Cut Test in cocoa Beans with Different Fermentation Levels 77
12 Fermentation Index of Cocoa Beans with Different Fermentation Levels ........................ . ......... . . ............................ 80
13 Fat Content of Cocoa Beans with Different Fermentation Levels . . . .............................. ......... .............................................. 82
viii
14 Melting Temperature of Cocoa Butter of Different Fermentation I..evels .................................. ........... ... ... ........... ... 83
15 pH and Titratable Acidity of Cocoa Beans with Different Fermentation I..evels ................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
16 Non - Volatile Acid of Cocoa Beans with Different FerDlen"tation I..evels ............................... ................... .............. 89
17 Volatile Acid of Cocoa Beans with Different FerDlenmtion I£v'els ................ . ............................................... 90
18 Polyphenol and Alkaloids in Cocoa Beans with Different Ferment:ation I..evels ................................................. ............ ... 94
19 Triglyceride in Cocoa Butter of Different Fermentation I..evels ......................................................................................... 96
20 Fatty Acids of Cocoa Butter of Different Fermentation I..evels .......................................................................... .......... ..... 97
21a Solid Fat Content of Cocoa Butter with Different Fermentation I..evels (Malaysia)............................................. 98
21b Solid Fat Content of Sulawesian Cocoa Butter of Different Fermentation I..evels (Sulawesian) ......................... ................ 99
22 Sensory Evaluation of Cocoa Beans of Different Fermentation I..evels compared to Ghanaian Beans ..................................... 102
23 Codes of Malaysian and Sulawesian cocoa bean blends....... 109
24 Fermentation Index of Malaysian and Sulawesian Cocoa Blends ........................................................................................ 112
25 Fat Content of Malaysian and Sulawesian Cocoa Blends ..... 115
26 Polymorphism of Malaysian and Sulaweisan Cocoa Butter Blends after Tempering ............................................................ 118
ix
27 Polymorphism of Malaysian and Sulawesian Untempered Cocoa Butter Blends .............. ................................................... 119
28 Melting Temperature of Different Malaysian and Sulawesian Cocoa Blends ............... ...... ... ................ ....... ...... ... 122
29 Solid Fat Content of Different Malaysian and Sulawesian Cocoa Blend . ............................................................................. 124
30 pH of Malaysian and Sulawesian Cocoa Blends .................. 126
31 Non-Volatile Acid in Malaysian and Sulawesian Cocoa Blends ........................................................... ...... ........................ 130
32 Volatile Acid of Malaysian and Sulawesian Cocoa Blends ... 132
33 Sensory Analysis of Malaysian and Sulawesian Cocoa Blends . .......................................................... ............................. 141
34 Ranking of Different Malaysian and Sulawesian Cocoa Blends ....... .................................................................................. 143 "
35 Production of Cocoa Beans in the World, Asia and Oceania Region....................................................... .. ............................... 157
36 Average Price of Cocoa Beans..... ............................................ 158
37 Production of Raw Cocoa in Malaysia and Indonesia ......... 159
38a Non-volatile Acids in Commercial Beans from Different Sourees ........... ....... .... .... ... ..... ....... ............... ..... .......... .... .... ... .... 160
38b Volatile Acid from Commercial Beans of Different Sources ... 160
39 Epicatechin in Commercial Cocoa Samples of Different
40
Sourees .............. .................................................... ...................... 161
Polymorphism and Melting Point of Cocoa Butter .............. 162
x
Abstract of the thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science.
CHARACTERISTICS OF MALAYSIAN AND SULAWESIAN COCOA BEANS AND THE OPTIMISATION OF QUALITY THROUGH
BLENDING
By
LEOW MIN MIN
August, 1999
Chairman Professor Jinap Selamat, PhD
Faculty Food Science and Biotechnology
Commercial Malaysian and Sulawesian cocoa were found to be
significantly different (p<O.OS) in the aspect of bean quality, fermentation
index, fat content, polyphenol, alkaloids, volatile and non volatile acids. In
other aspects such as melting point (cocoa butter), triglyceride, fatty acids
and solid fat content (SFq the difference was found to be insignificant
(p>O.OS). More purple bean was found in the Sulawesian beans (78%)
compared to the Malaysian beans (4%). The high content of polyphenol
(epicatecbin = 34.72 mgj g) and alkaloids (theobromine = 30.40 mgj g,
caffeine=0.678 mgj g) in Sulawesian beans showed a sign of under-
xi
fermentation. Fermentation index further verify Sulawesian· beans (0.622) as
under- fermented compared to the Malaysian beans (1.524). Cocoa beans
with different fermentation level exhibited significant difference in cut test,
melting temperature (Malaysian beans only), volatile and non-volatile acid,
polyphenol, alkaloids, solid fat content and taste. Melting temperature of the
Malaysian cocoa butter increase with fermentation. Non-volatile acids such
as lactic, succinic and citric increased but malic and oxalic acids decreased
with fermentation. All the volatile acid but propionic acid increased with
fermentation. On the other hand, polyphenol and alkaloids decreased
drastically as fermentation proceeds. In the aspect of taste, all less fermented
cocoa beans from Malaysia and Sulawesi were more bitter and astringent
but the more fermented cocoa beans produces cocoa liquor with a more sour
taste. The qualities that the blended cocoa beans needs to express are a better
cocoa/ chocolaty taste, less bitter, less astringent, less sour and preferably
with the presence of nutty flavour. Cocoa blends found to have the most
favourable taste are blends of 4 days fermented Malaysian cocoa beans and 2
days fermented Sulawesian beans at the ratio of 75:25 (I2M4/25) and blends
of 6 days fermented Malaysian cocoa beans and 2 days fermented
Sulawesian beans at the ratio of 25:75 (I2M6j75).
xii
Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains
CIRI-CIRI KOKO MALAYSIA DAN SULAWESI DAN OPTIMISASI KUALITI MELALUI CAMPURAN
Oleh
LEOW MIN MIN
Og05,l999
Pengerusi Professor Jinap Selamat, PhD
Fakulti Sains Makanan dan Bioteknologi
Koko komersil dari Malaysia dan Sulawesi menunjukkan perbezaan
ketara (p<O.05) dari segi kualiti biji, indeks fermentasi, kandungan lemak,
polifenol, alkaloid, asid meruap dan tidak meruap. Aspek lain seperti takat
lebur (mentega koko), trigliserida, asid lemak dan kandungan lemak pejal
tidak menunjukkan perbezaan yang ketara (p>O.OS). Lebih kotiledon yang
bewarna ungu dikesan dalam koko Sulawesi (78%) dibandingkan dengan
koko Malaysia (4%). Kandungan tinggi polifenol (epikatekin=34.72 mg/g)
dan alkaloid (thiobromin=30.40 mg/ g, kaffein=O.678 mg/ g) dalam koko
Sulawesi memberi petanda bahawa ia tidak difermentasi dengan sempurna.
xiii
Index fermentasi juga menunjukkan bahawa koko Sulawesi (0.622) kurang
difermentasi banding dengan koko Malaysia (1.524). Biji koko yang
mempunyai tahap fermentasi yang berIainan menunjukkan perbezaan yang
ketara dari segi ujian keratan, takat lebur (koko Malaysia sahaja), asid
meruap dan tidak meruap, polifenol, alkaloid, kandungan lemak pejal dan
rasa. Takat lebur bagi mentega koko Malaysia didapati meningkat dengan
fermentasi. Asid tidak meruap seperti asid-asid laktik, suksinik dan sitrik
meningkat tetapi asid malik dan oksalik menurun dengan fermentasi.
Semua asid meruap kecuali asid propionik meningkat dengan fermentasi. Di
samping itu, polifenol dan alkaloid menurun dengan ketara dengan
peningkatan tahap fermentasi. Dari segi rasa, semua koko yang kurang
difermentasi dari Malaysia dan Sulawesi adalah lebih pahit dan kelat tetapi
koko yang mengalami tahap fermentasi yang lebih lama didapati lebih
masam. Kualiti yang perIu ditonjolkan oleh koko campuran adalah rasa
koko / coklat yang lebih baik, kurang pahit, kurang kelat, kurang masam dan
sebaik-baiknya dengan kehadiran rasa kacang. Campuran koko yang
mempunyai rasa y ang terbaik adalah campuran dari koko Malaysia yang
difermentasi 4 hari dengan koko Sulawesi yang difermentasi 2 hari pada
nisbah 75:25 (I2M4/25) dan campuran dari koko Malaysia yang difermentasi
6 han dengan koko Sulawesi yang difermentasi 2 haripada nisbah 25:75
(I2M6/75).
xiv
CHAPTER I
GENERAL INTRODUCfION
Background
Cocoa trees originated from the American tropicS in the region of
the Amazon and belong to the genus TheolJroma. TheolJroma cacao belongs
to the family Sterculiaceae. Unnaues gave the cocoa tree its name in the
first edition of his 'Species Plantarum' published in 1753. In 1964
Cuateccasas further divided the genus into 6 groupings containing 22
species of which TheolJroma is the only species of commercial value. Other
better known species in the genus are TheolJroma bicolor and TheolJroma
grandiflorum. T. Bicolor is atypical of the genus as its inflorescence appears
in the axils of the new leaves. It's large heavy pods are borne on the ends
of the branches, which bend downwards when the pods reach maturity.
The beans have white cotyledons and in size are similar to small cocoa
beans known as 'pataste'. They are used as an adulterant of cocoa in
Central America. Theobroma grandijlorum also known as 'Cupuacu' in Brazil
is well liked locally for the delicate flavour of the mucilage around the
bean (Woods and Lass, 1985).
The growth parameters required by cacao trees are fairly precise.
The areas of cultivation lie within the rain forest regions of the western
1
2
hemisphere from 18°N to 15°5 latitudes of the equator. The suitable
temperature range for it's growth is around 21°C - 32°C accompanied by
rainfall of about 1,150 mm - 2,500 mm per year. In counbies with defined
wet and dry season, the main harvest of cocoa will be obtained 5-6 months
after the start of the wet season (Bridgland, 1953).
Among the subspecies of the species Theobroma CllCIIO, only 2 of them
are of any commercial value. Those are the Forestero and the Criollo, and it
includes a cross between the two which is the Trinitario (Wood and Lass,
1985). The physical and chemical characteristics of these two cocoas differ
significantly even though they are from the same genus. The Criollo
subspecies are found mostly in the populations of Central and South
America and the Forestero subspecies are found in all the other
populations.
Cocoa in Malaysia originated from the Amazon region in Latin
America and was known to have reached Sabah as early as 1700. Cocoa
was first observed in Malaysia in the year 1778 in Malacca. In the year
1882, a 20 years old cocoa tree was observed to be fruiting well in Sabah,
which was then known as British North Borneo (Anon, 1996a).
3
The cultivation of the cocoa tree first started as an experiment at the
then Agricultural Research Station in Serdang and also at the Agricultural
Experimental Station in Silam, Sabah. Serious cultivation of the cocoa did
not start until the end of the second world war, when the government was
looking for a crop to supplement the contribution of rubber. As a result, in
1950, seedlings from West Africa, mostly of the Forestero type, were
imported and tested in the volcanic soils of Tawau, Sabah and also in the
Tarat Research Station in Sarawak (Wyrley-Birch, 1976). The first
commercial estate was established in 1950 at Jerangau, Trengganu
followed by the estates of the Borneo Abaca Ltd company in Sabah in 1955.
Commercial planting of cocoa in Malaysia commencing in the
1950's, saw expansion in the late 1970's and early 1980's due to the high
prices fetched by cocoa beans. However, world production of cocoa beans
have been declining from the early 1980's caused by a drastic drop in cocoa
prices due to over supply. Given the scenario, decrease is anticipated in
both planted areas and the production of cocoa at marginal rates of 1.4%
and 1.8% per annum respectively in the period of 1991-2010 (Ministry of
Agriculture, 1992).
Currently, Malaysian cocoa faces problems of quality and of
relatively high production costs, due largely to labour shortages and the
associated escalation in labour costs. Other additional factors that have
4
contributed to the closure of estates are the problem of insect infestation,
particularly cocoa pod borers, and also competition from other more
profitable crops such as oil palm and coconut The recent and ongoing East
Asian economy crisis might trigger a comeback of Malaysian cocoa
production, given that cocoa is traded in u.s. dollars. But the process of
replanting the cocoa trees takes time. Even then, other more profitable
crops will outweigh the 'push' for increasing the area under cocoa
cultivation.
Cocoa in Indonesia was mainly cultivated in estates, but from the
year 1924-1929, an increase in smallholders production was noted (Fadhil
and Darmawan, 1994). Increased cocoa production in the 1970s, in
Indonesia has also contributed to the increase in world cocoa production.
Indonesia has a long history as a cocoa producing region. Beans from
Indonesia, in particular from Sulawesi, were usually not fermented or
under fermented, since fermentation of cocoa beans is not a common
practice among local farmers there. These beans, when used to produce
cocoa liquor, of low quality. The flavour will not be fully developed and
the presence of extreme bitterness will be detected. These beans are known
to produce lower quantity of butter in comparison to the fully fermented
ones. Sulawesian beans also pose problems to grinders. The lower cocoa
butter content can give rise to poor flow properties during grinding.
5
Cocoa in Indonesia is produced largely from small holders. They
accounted for about 70% of the cultivated cocoa area and 60% of the cocoa
production in 1993 (Fadhil and Darmawan, 1994). The rapid expansion of
cocoa plantations in Indonesia was due largely to the international
competitiveness, the support of the government in distributing high
yielding seeds, the availability of fertile land and the spontaneous
migration of its people (Fadhil and Darmawan, 1994). Since 1992,
Indonesia has maintained its position as the world's fourth largest cocoa
producer.
In the last 7 years, the area brought under cocoa cultivation in
Indonesia have shown a significant increase with the south and southeast
Sulawesi accounting for 20% of the total cocoa area planted. The planted
areas in North Sulawesi account for another 14%. The centers of the cocoa
cultivation in Indonesia, which were dominated by the North Sumatera
and East Java regions have now been shifted to south and south east
Sulawesi. In Indonesia, cocoa cultivation is still profitable due to the low
cost of labour and land. Hence, cocoa production in Indonesia is still on the
increase.
6
Significance of this study
A tremendous amount of efforts has been made to improve the
quality of Malaysian beans. It is hence discouraging to know that cocoa
cultivation in Malaysia is diminishing. The decreasing supply of cocoa
beans are attributed to the problems mentioned aforehand. Thus, it is
opportune to source other means of obtaining good cocoa beans. Importing
cocoa beans from other countries is one such possibility but the cost of
obtaining good quality cocoa beans may prove to be too high. Sulawesian
cocoa beans being un- or under fermented are of inferior quality to
Malaysian beans. It can however be improved upon. H such efforts are
successful, these cocoa beans may be used to produce more economical
cocoa based products.
It is known that fermentation improves the flavour qualities of
cocoa beans. It also improves the appearance of cocoa beans. Besides
fermentation, genotypes also play an important role in the flavour quality
of cocoa beans. The fermentation period of the cocoa beans is dependent,
in some cases on the genotype as well. Therefore, the objectives of this
study were:
a) To determine the physico-chemical qualities of commercial
Malaysian and Sulawesian cocoa beans using Ghanaian beans as a
standard.
7
b) To determine the physico-chemical qualities of Malaysian and
Sulawesian cocoa beans under controlled fermentation periods
namely 0, 48, 96 and 144 hours.
c). To determine the physico-chemical qualities of blended cocoa liquor
and the best blending combination based on physico-chemicaJ
qualities and sensory requirements.
CHAPTER II
LITERATURE REVIEW
Introduction
Cocoa bean quality is dependent on factors such as genetics,
environment physiology and process technology (Biehl et al., 1990). These
three factors tend to vary bean quality in the different producing countries
primarily due to tradition and circumstances. Thus, cocoa beans from
different producer countries vary in flavour. This study mainly focused on
the process technology especially the effect of fermentation on cocoa
flavour.
Harvesting
Cocoa pods take 4-5 months to grow to full size following
pollination (Seeschaaf, 1971). The pods are then left on trees to ripen for
about a month before harvesting. Composition of the cocoa pulp and its
cotyledon (Table 1 & 2) depends on a few factors such as genotype,
maturity and also environmental factors. During ripening the
mucilaginous pulp surrounding the beans undergoes certain chemical and
physical changes critical to successful fermentation (Ostavar and Keeney,
8
9
1973). On harvesting, the ripe pod is removed from the tree by cutting the
peduncle to avoid damaging the tree. As all the pods on a tree do not
mature simultaneously, the farmer must make repeated passes through the
cocoa field to gather ripened pods. Premature harvesting will result in
inferior beans. On the other hand, a prolonged delay in harvesting may
result in beans germinating inside the pods (Shaughnessy, 1992). Using
Malaysian beans, Lewis and Lee (1985) have demonstrated that the time of
harvesting and pod storage are two major factors affecting chemical
qualities associated with cocoa flavour. Mac Lean and Wickens (1951)
found that fermentation of overripe pods result in a lower percentage of
purple beans than would be obtained by fermentation of ripe or under ripe
pods.
Harvesting is usually carried out over a period of 3-4 days, at
intervals of three weeks (Lopez, 1986). Pods are split open immediately
after harvesting and the wet beans are extracted. Sometimes the harvested
pods are kept for a number of days, in a process known as pod storage.
This pod storage process will increase labour costs as it involves double
handling and transportation of pods after harvesting. It also increases the
risk of cocoa pod borer infestation (Day, 1985). Despite, the significant
improvement in cocoa flavours after 4 days of pod storage, it is still not
practised in larger plantations or farms in Malaysia and Indonesia (Arikiah
et al., 1994) because of these negative factors.
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Fermentation
Post harvest treabnents such as pod storage, fermentation, drying
and roasting are crucial in the formation of desirable chemical and
physical properties. Fermentation is the first stage in preparing the cocoa
bean for the market The process of fermentation starts immediately after
the splitting of the cocoa pod (Kim and Keeney, 1984). The whole process
involves extraction of cocoa beans from the pods, the liquefication of the
pulp caused by anaerobic yeast ijinap, 19(4) followed by the adherence of
the cocoa pulp to the beans. These processes create the reactions necessary
for the production of cocoa beans of high quality.
The basic requirement for satisfactory fermentation is that it should
commence within 24 hours of pod splitting. It requires maintenance of
heat, draining of sweatings and provision of' an adequate and constant
access to air (Wood and Lass, 1985). Fermentation temperature and
constant access to air are not solely dependant on each other but is also
influenced by fermentation batch size (Rohan, 1963). Any reduction in
batch size is usually accompanied by an increase in the uniformity and rate
of fermentation throughout the mass, but poses a difficulty with regard to
insulation of heat Throughout the fermentation process, the beans are
normally turned once or twice for the purpose of aeration (Wood and Lass,
1985).
