J Food Sci Technol (November–December 2013) 50(6):1097–1105
DOI 10.1007/s13197-011-0446-5
ORIGINAL ARTICLE
Chemical composition and physical quality characteristics
of Ghanaian cocoa beans as affected by pulp
pre-conditioning and fermentation
Emmanuel Ohene Afoakwa & Jennifer Quao &
Jemmy Takrama & Agnes Simpson Budu &
Firibu Kwesi Saalia
Revised: 11 April 2011 /Accepted: 28 June 2011 /Published online: 15 July 2011
# Association of Food Scientists & Technologists (India) 2011
Abstract Investigations were conducted to evaluate the reductions in shell content and no appreciable changes in
effects of pod storage (as a means of pulp preconditioning) germ proportions were noted.
and fermentation on the chemical composition and physical
characteristics of Ghanaian cocoa beans. A 4×2 full Keywords Theobroma cacao . Pod storage . Forastero .
factorial design with factors as pod storage (0, 7, 14, Fermentation . Chemical composition . Physical quality
21 days) and cocoa treatment (fermented and unfermented)
were conducted. Samples were analyzed for their chemical
composition (moisture, crude fat, crude protein, ash and
Cocoa is one of the most important agricultural export
carbohydrate content) and mineral content using standard
commodities in the world and forms the backbone of the
analytical methods. The physical qualities of the beans were
economies of some countries in West Africa, such as Cote
analyzed for their proportions of cocoa nibs, shells and
d’Ivoire and Ghana. Cocoa beans are the fermented and
germ. Fermentation and increasing pod storage resulted in
dried seeds of Theobroma cacao, and the fundamental
significant (P<0.05) decreases in ash (3.48–2.92%), protein
ingredient in chocolate manufacture. It is generally known
(21.63–17.62%) and fat (55.21–50.40%) content of the
to have originated from Central and Southern America.
beans while carbohydrate content increased from 15.47% to
Currently, three broad cultivars of cocoa are commonly
24.93% with both treatments. As well, increasing pod
recognized: Forastero, Criollo and Trinitario. The cultivars
storage and fermentation significantly (P<0.05) increased
exhibit differences in the appearance of pods, yields of
the copper content of the beans from while reductions in
beans, flavour characteristics and in resistance to pests and
Mg and K occurred. Amongst the minerals studied,
disease (Wood and Lass 1985; Asiedu 1989; Afoakwa et al.
potassium was the most abundant mineral followed by
2008; Afoakwa 2010; Adeyeye et al. 2010). Cocoa is
magnesium, phosphorus and calcium in the fermented
largely produced in developing countries, but is mostly
cocoa beans. Proportion of cocoa nibs also increased from
exported to and consumed in industrialized countries.
with increasing pod storage and fermentation whiles
Measured by volume of exports, the two main cocoa
producing countries are Cote d’Ivoire and Ghana with an
E. O. Afoakwa (*) : J. Quao :A. S. Budu : F. K. Saalia average annual production of ca. 40% and 20% respective-
Department of Nutrition & Food Science, University of Ghana, ly, making ca. 60% of global production. In 2008, West
P. O. Box LG 134, Legon, Africa alone accounted for ~71% of global cocoa supply
Accra, Ghana (ICCO 2009).
e-mail: e_afoakwa@yahoo.com
In Ghana, cocoa has been labelled ‘the golden pod’
E. O. Afoakwa owing to the pivotal role it plays in the nation’s economy.
e-mail: eafoakwa@ug.edu.gh It is cultivated on about 1.5 million hectares of land by
some 800,000 families in six out of the ten regions. It is
J. Takrama
Cocoa Research Institute of Ghana, cultivated almost exclusively by small-holder farmers
P. O. Box 8, New Tafo, Akim Eastern Region, Ghana with average farm sizes of about 4.0 ha and mean
1098 J Food Sci Technol (November–December 2013) 50(6):1097–1105
production yields of 246.4 kg/ha (Afoakwa 2010; fermentation. The pulp is the substrate metabolised during
Knudsen and Fold 2011). The major cocoa type cultivated fermentation by a sequence of bacteria and fungi (Ostovar
by farmers throughout Ghana is the Forastero variety with an and Keeney 1973), and since the properties of the substrate
average proportions cultivated cultivars being Amazonica determine microbial development and metabolism, changes
(34.4%), the Amelonado (13.3%) and the hybrid (52.3%) in the pulp may affect the production of acids by lactic acid
(Afoakwa 2010). bacteria, yeasts and acetic acid bacteria. Three basic processes
Cocoa beans are mostly processed into chocolate and of pulp pre-conditioning have been evaluated for the treatment
cocoa products using a wide range of intermediate products of fresh cocoa beans prior to fermentation – pod storage,
such as cocoa liquor, cocoa butter, cocoa cake and raw mechanical or enzymatic depulping and bean spreading
cocoa powder. Cocoa powder is essentially used in (Rohan 1963; Wood and Lass 1985; Biehl et al. 1989;
flavouring biscuits, ice cream and other dairy products, Schwan and Wheals 2004).
drinks and cakes and in the manufacture of coatings for Traditionally, Ghanaian farmers have unknowingly
confections and frozen desserts (Afoakwa et al. 2007; adopted this technique of pod storage by their practice of
Pandey and Singh 2011; Frost et al. 2011; Rossini et al. using family labour to collect the harvested pods into piles
2011). It is also used in the beverage industry, for example 3–5 days before organizing friends and neighbours to help
in the preparation of chocolate milk. Cocoa butter is used in break open the pods prior to fermentation (Duncan 1984).
the manufacture of chocolate confectionery, soap and This method of pod storage appears to have highly
cosmetics (Ntiamoah and Afrane 2008; Schumacher et al. beneficial effect on the chemical composition and subse-
2010). Other by-products such as cocoa pulp juice is also quent development of chocolate flavour, though the precise
fermented to produce industrial alcohol and alcoholic chemical and biochemical effects, conditions and processes
beverages such as brandy and wine (Jayathilakan et al. still remain unknown. With increasing specialty niche
2011). Currently, the pod husks and shells are used for the products in chocolate confectionery, understanding the
preparation of animal feed and fertilizer in Ghana factors contributing to variations in the chemical composi-
(Ntiamoah and Afrane 2008). The unique culture of tion and physical qualities of cocoa beans during pod
producing high quality dried cocoa beans in Ghana, as storage and subsequent fermentation processes would have
engraved in the traditional farming practices of the peasant significant commercial implications. Thus, this work
farmers, coupled with rigorous research and quality investigated effects of pod storage (as a means of pulp
control programmes embarked upon consistently by pre-conditioning) and fermentation on the chemical com-
successive Governments to date, has guaranteed Ghanaian position and physical quality characteristics of Ghanaian
cocoa its premium status on the international market. cocoa beans.
Processing of cocoa beans into various cocoa and
chocolate products starts with an on-farm fermentation of
the beans followed by drying, and roasting during industrial Materials and methods
processing. These postharvest processes are very crucial to
the quality of finished products as they initiate the Materials
formation of chocolate flavour precursors and the brown
colour of cocoa products (Schwan et al. 1995; Adeyeye et Ripe cocoa pods from mixed hybrids were harvested from
al. 2010). The fermentation process breaks down the the experimental plots of Cocoa Research Institute of
mucilaginous pulp surrounding the beans and causes Ghana (CRIG), Tafo in the Eastern Region of Ghana. The
cotyledon death (Sanchez et al. 1985; Gotsch 1997; cocoa pods were selected according to their ripeness and
Afoakwa et al. 2008). This triggers biochemical transfor- maturity levels. The beans were pulp preconditioned by
mation inside the beans, leading to reduction in bitterness storing the harvested pods for a period of time before
and astringency, development of flavour precursors such as, splitting. About 1,200 pods were stored (on the cocoa
free amino acids, peptides and sugars (Thompson et al. plantation) at ambient temperature (25–28 °C) and relative
2007; Kratzer et al. 2009; Rodriguez-Campos et al. 2011). humidity of 85–100% for periods of 0, 7, 14 and 21 days
Cocoa fermentation is influenced by many factors such as respectively. The respective pods were then split after these
type of cocoa, disease, climatic and seasonal differences predetermined storage times and fermented using the
(Afoakwa 2010), turning, batch size (Lehrian and Patterson traditional heap method.
1983), quantity of beans (Mamot and Samarakhody 1984; The fermentation was done by heaping about 50 kg of
Wood and Lass 1985) and also pulp pre-conditioning the extracted cocoa beans on the fermenting platform
(Meyer et al. 1989). covered with banana leaves. The heaped beans were again
Pulp pre-conditioning entails changing the properties of covered with banana leaves and fermented for 6 days with
the pulp prior to the development of microorganisms in consecutive openings and turnings after every 48 h.
J Food Sci Technol (November–December 2013) 50(6):1097–1105 1099
Samples of the unfermented beans were picked into a sterile When the digestion was completed, the solution was cooled
polythene bag under aerobic conditions and after the sixth slightly and 30 ml of distilled water added. The mixture
days of fermentation, for drying and subsequent analysis. was brought to boil for about 10 min and filtered hot into a
After each sampling time , the samples were immediately 100 ml volumetric flask using a Whatman No. 4 filter
transported to the laboratory for drying by spreading the paper. The solution was then made to the mark with
cocoa beans approximately 5 cm deep on metal trays distilled water.
(40 cm×60 cm), and placed in a temperature controlled,
forced air oven for about 24 h at a temperature of 45–50 °C Determination of Ca, Mg, Zn, Fe, Cu, Na and K
until dried (to moisture content below 8%). The dried beans
were bagged in airtight black plastic bags and stored at The concentrations of Ca, Mg, Zn, Fe, Na and K were
ambient temperature (25–28 °C) in a dark room free from determined using Spectra AA 220FS Spectrophotometer
strong odours until used. Prior to chemical analyses, the (Varian Co., Mulgrave, Australia) with an acetylene flame.
dried samples were milled using a hammer mill (Model 2A, One (1) ml aliquots of the digest was used to determine the
Christy and Norris Ltd., Chelmsford, England) and the Ca, Mg, Zn, Fe, Cu, Na and K content of the samples.
resulting liquor packed in a black polyethylene bags and
used. Phosphorus determination
Experimental design Two (2) ml aliquot of the digest was reacted with 5.0 ml
molybdic acid. The molybdic acid was prepared by
A 4×2 full factorial design with experimental factors as pod dissolving 25 ml of ammonium molybdate in 300 ml
storage (0, 7, 14, 21 days) and cocoa treatment (fermented distilled water; with 75 ml of concentrated sulphuric acid
and unfermented) were conducted. The samples were in125 ml of water to get 0.5 L of molybdic acid. One (1) ml
analyzed for their chemical composition moisture, crude each of 1% Hydroquinone and 20% Sodium sulphite was
fat, crude protein, ash and carbohydrate content (AOAC added in that sequence, and the solution was made up to
2005). Mineral analyses were also determined using 100 ml and allowed to stand for 30 min in order to develop
Atomic Absorption Spectrophotometer. The physical qual- colour after which the absorption was measured at 680 nm.
ities of the beans were analyzed for their proportions of A standard curve of colorimetric readings versus concen-
cocoa nibs, shells and germ. tration of phosphorus using portions of standard phospho-
rus solutions (1 ml, 2 ml and 3 ml) subjected to reactions
Methods with molybdic acid, hydroquinone and sodium sulphate
solutions were drawn. All readings were corrected using a
Proximate analysis blank to eliminate the effect of any colour produced by the
reagents.
The moisture, crude fat, crude protein and ash were
determined following the procedures in AOAC (2005) Physical quality analyses
methods 931.04, 963.15, 970.22 and 972.15 respectively.
Carbohydrate was determined using ‘by difference’ method. Percentage nib, shell and germ
All the analyses were performed in triplicate and the mean
values reported. The percentage nib, shell and germ were determined
according to the method described by Wood and Lass
Mineral analyses (1985). One hundred (100) grams of cocoa beans sample
was weighed and the nibs carefully separated from the
Mineral analyses were determined using AOAC (2005) shells using a sharp knife and weighed separately. The germ
methods with slight modifications. About 0.5 g of the were then carefully separated from the nibs and weighed.
sample was weighed into a 250 ml beaker. Twenty five ml The percentage nib, shell and germ were calculated. The
(25 ml) of concentrated nitric acid was added and the analyses were carried out eight times and the mean values
beaker covered with a watch glass. The sample was reported.
digested with great care on a hot plate in a fume chamber
until the solution was pale yellow. The solution was cooled Statistical analyses
and 1 ml perchloric acid (70% HCLO4) added. The
digestion was continued until the solution was colourless The data were analysed using Statgraphics software version
or nearly so (the evaluation of dense white fumes was 3.0 (STSC Inc, Rockville, MD, USA) for analysis of
regarded to be indicative of the removal of nitric acid). variance (ANOVA). Least significant difference (LSD) was
1100 J Food Sci Technol (November–December 2013) 50(6):1097–1105
used to separate and compare the means and significance results indicate that protein content was significantly
was accepted at 5% level (p<0.05). All treatments were influenced (p<0.05) by pod storage and fermentation time
conducted in triplicates and the mean values reported. (Table 2). Further analysis using Least Significance
Difference (LSD) revealed that the decreases amongst the
7 and 14 days pod storage were not significantly different.
Results and discussion The protein content of the fermented cocoa beans reduced
from 18.80 to 17.60% by 14 days of pod storage. The
Chemical composition of pulp preconditioned fermented protein content was significantly reduced after 6 days of
and unfermented dried cocoa beans fermentation from 21.63 to 18.80% for the beans that were
not stored (0 day pod storage) and likewise in all the beans
Proximate composition that were pulp preconditioned (7, 14 and 21 days pod
storage). These trends were consistent with reported
Table 1 shows the proximate composition of unfermented literature by Biehl and Passern (1982), Biehl et al.
and fermented cocoa beans under different pod storage (1985) and Crouzillat et al. (1999). Contrary to this,
periods. The moisture levels of the cocoa beans were Aremu et al. (1995) reported a significant increase in bean
considerably lower (3.89–4.95%) than the acceptable limits protein content by the sixth day of fermentation. The
(6–7%) for long term storage of cocoa (Wood and Lass observed decreases in protein content with pod storage and
1985; Dand 1997; Fowler 2009) hence the beans were quite fermentation might be due to protein breakdown during
brittle in nature. These relatively lower moisture content the curing process, occurred partly due to hydrolysis to
attained was to ensure that virtually all microbial and amino acids and peptides and partly by conversion to
enzymatic reactions had ceased. Although the fermentation insoluble forms by the action of polyphenols as well as
process reduced the water content of the beans there was losses by diffusion (Afoakwa et al. 2008; Afoakwa and
still considerable amount of moisture lost during drying, Paterson 2010).
thus confirming previous findings (Páramo et al. 2010). Fat content or yield is an important quality index for
Fermentation introduced significant variation in the mois- cocoa processors during purchasing of fermented cocoa
ture levels (Table 2). Moisture levels were significantly beans. In West African fermented and dried cocoa beans,
lower (p<0.05) in all pulp preconditioned fermented cocoa the fat content ranges between 56 and 58% and most
beans than in the unfermented beans (Table 1) and this may Forastero cocoas fall between 55 and 59% (Rohan 1963;
be ascribed to the initial higher moisture levels of Reineccius et al. 1972; Wood and Lass 1985; Afoakwa et
unfermented bean samples. al. 2008). The fat content of the beans as observed in this
Crude protein content ranged from about 16 to 22% study were slightly lower than the reported values.
and this was comparable to literature values of 15.2– Generally, the fat content ranged from 50.40 – 53.35%
19.8% (Aremu et al. 1995; Afoakwa et al. 2008). There and 52.27 – 55.21% respectively for the pulp pre-
were general decreases in crude protein with fermentation conditioned fermented and unfermented beans. The fat
for all the cocoa samples. Similarly, apparent decreases content noted in the beans from the unstored pods were
were observed as pod storage increased (Table 1). The 53.35% and 55.21% for the fermented and unfermented
Table 1 Effect of pod storage (pulp pre-conditioning) and fermentation on proximate composition of cocoa beans
Pod storage (Days) Fermentation condition Moisture (%) Protein (%)a Fat (%) Ash (%) Carbohydrate (%)b
0 Unfermented 4.2 ±0.02 21.6 ±0.83 55.2±0.10 3.5 ±0.11 15.5 ±0.63
Fermented 4.0 ±0.02 18.8 ±0.56 53.4 ±0.63 2.8 ±0.07 21.0 ±0.08
7 Unfermented 4.4 ±0.04 20.8 ±0.05 53.3 ±1.5 2.9 ±0.05 18.6 ±0.72
Fermented 4.3 ±0.09 18.2 ±0.13 52.2 ±0.05 2.3 ±0.04 23.1 ±0.54
14 Unfermented 4.2 ±0.02 19.7 ±0.06 52.5 ±0.04 3.1 ±0.01 20.5 ±0.24
Fermented 4.5 ±0.03 17.6 ±0.60 50.5 ±0.15 2.7 ±0.18 24.7 ±0.31
21 Unfermented 4.9 ±0.01 20.4 ±0.48 52.3 ±0.07 3.3 ±0.05 19.1 ±0.09
Fermented 3.8 ±0.04 17.9 ±0.07 50.4 ±0.05 2.9 ±0.09 24.9 ±0.11
a Protein (N×6.25) b Carbohydrate was obtained using by difference method
Results presented are mean values of triplicate analysis±standard deviation
J Food Sci Technol (November–December 2013) 50(6):1097–1105 1101
Table 2 ANOVA summary table
showing F-ratios for variations in Variables Protein Fat Carbohydrate Ash Moisture
proximate composition of pulp
pre-conditioned fermented and Pod storage (PS) 15.3* 166.5* 47.3* 28.4* 2.4
unfermented cocoa beans Fermentation time (FT) 16.1* 543.3* 397.7* 115.9* 16.9*
Interaction (PS x FT) 3.1 15.8* 3.3 3.1 23.8*
* Significant at p<0.05
beans respectively. Increasing pod storage, however, caused Pod storage influenced the carbohydrate content signifi-
consistent reduction in the fat content of the cocoa beans cantly (p<0.05) (Table 2). Further analysis by LSD
such that after 21 days of pod storage, the fat content had showed that samples stored for 0, 7, 14 and 21 days
decreased to 50.40% and 53.35% respectively for the were significantly different from each other. An apparent
fermented and unfermented samples. The observed varia- inverse relationship appears to exist between the levels of
tions in the fat content of the beans prior to pod storage and fat and total carbohydrate in fermenting cocoa. Conver-
fermentation might be attributed to the relatively lower sion of lipid to carbohydrate via gluconeogenesis,
sizes of cocoa beans used in this study. Variations in the employing the glyoxylate cycle could not be ruled out.
bean sizes could also account for the observed relatively It has been indicated that this pathway normally operates
lower fat content. Wood and Lass (1985) and Dand (1997) in microorganisms and germinating oil seeds (White et
reported that smaller beans size results in lower fat yield. al. 1978).
Analysis of variance (ANOVA) on the data revealed that The ash content of the cocoa beans decreased signifi-
the fat content of the samples decreased significantly (p< cantly (p<0.05) with fermentation and was generally
0.05) with fermentation and pod storage (Tables 1 and 2) comparable to literature values (Rohan 1963; Reineccius
and this corroborate studies carried out by Aremu et al. et al. 1972; Aremu et al. 1995). ANOVA indicated that the
(1995) in Nigeria where the lipid content of the cocoa beans reductions in the ash contents due to fermentation and pulp
decreased from 62.9% to 55.7% by the sixth day of preconditioning were significant (p<0.05), however pod
fermentation. This suggests that the reductions in fat storage of 7 days were significantly lower than the other
content in cocoa beans could be avoided by reducing pod storage days (Table 2).
fermentation time. Again, the consistent decreases in fat
content noted with increasing pod storage might have Mineral content of pulp pre-conditioned fermented
resulted from the action of lipase enzymes which break- and unfermented cocoa beans
down the triglyceride in the beans into its separate groups
of fatty acids, thereby increasing the free fatty acids levels The effect of pulp preconditioning on the mineral compo-
leading to the production of rancid flavour in the beans sition of fermented and unfermented cocoa samples are
from the prolonged stored pods. shown in Table 3. Generally, there were decreases in the
Carbohydrate content was significantly (p<0.05) micronutrients with fermentation and increasing pod stor-
higher in fermented samples than in unfermented samples age. The differences in mineral contents for all the different
(Table 2), with beans stored for 21 days prior to days of pod storage was significant (p<0.05). Also,
fermentation having the highest carbohydrate content. differences among the unfermented and their corresponding
Table 3 Effect of pod storage and fermentation on mineral content of cocoa beans
Pod storage Fermentation Mineral content (mg/100 g)
(days) condition
Fe Cu Mg Zn Na Ca P K
0 Unfermented 2.7±0.04 11.1±0.03 286.8±3.19 9.7±0.06 3.4±0.01 140.2±0.60 236.6±23.08 2313.1±6.04
Fermented 2.2±0.02 8.8±0.01 364.2±1.82 10.6±0.07 2.5±0.16 170.8±0.74 195.8±0.02 2557.9±11.01
7 Unfermented 2.5±0.02 11.5±0.13 318.6±7.27 9.3±0.06 2.5±0.04 141.1±0.60 264.4±184.62 2325.4±12.3
Fermented 1.8±0.01 13.2±0.05 262.7±3.68 8.2±0.01 3.0±0.01 143.5±0.08 210.5±23.08 2164.2±10.26
14 Unfermented 2.2±0.02 13.7±0.02 331.5±6.89 9.3±0.05 3.3±0.08 158.2±0.38 292.1±23.08 2433.7±16.23
Fermented 1.5±0.03 15.5±0.06 271.3±1.16 7.5±0.02 2.6±0.06 150.3±0.68 203.9±23.08 2095.6±6.98
21 Unfermented 1.4±0.01 15.3±0.12 349.2±2.98 9.4±0.25 2.7±0.04 142.8±0.07 381.9±46.16 2318.7±3.62
Fermented 1.2±0.02 17.3±0.07 322.3±5.59 15.6±0.52 2.0±0.06 148.5±0.41 355.7±00 2070.7±5.71
Results presented are mean values of triplicate analysis±standard deviation
1102 J Food Sci Technol (November–December 2013) 50(6):1097–1105
fermented samples were also significant (p<0.05). Iron significantly different from each other but the observed
generally decreased significantly (p<0.05) as pod storage significant reductions were due to the differences in values
days increased and with fermentation (Table 3 and 4). The from the 0, 7 and 21 days.
iron content of unfermented cocoa samples that were not Generally, phosphorus content decreased with fermenta-
stored prior to fermentation was 2.73 mg/100 g and this tion at all levels of pod storage (Table 3). Contrary to these,
decreased significantly by the end of the fermentation to increasing pod storage (pulp preconditioning) caused
2.21 mg/100 g by the end of the fermentation (Table 3). consistent increases in the phosphorus content (Table 3).
Similar trends were observed in the beans stored for the ANOVA on the data showed that both pod storage and
other days of pod storage. fermentation had significant (p<0.05) influence on the
Copper content on the other hand increased as phosphorus content (Table 4). Multiple comparison test
fermentation time and pod storage days increased. By (LSD) suggested that the phosphorus content at 0 and
21 days of pod storage, the copper content of both the 21 days of pulp pre-conditioning were significantly
unfermented and fermented cocoa beans samples had different from each other and as well those from 7 and
increased respectively from 11.1 to 15.3 mg/100 g and 14 days.
8.8 to 17.3 mg/100 g, suggesting approximately 100% Cocoa beans had very high potassium content with
increase in copper content in the fermented samples. This values of 2557.92 and 2313.12 mg/100 g respectively for
remarkable trend may be explained by the breakdown of both the fermented and unfermented samples from the
anti-nutritional factors such as polyphenols and tannins unstored pods (Table 3). Fermentation of the beans caused
during fermentation (Svanberg and Lorri 1997). Fermen- slight reduction in the samples to 2070.74 mg/100 g after
tation is known to provide optimum pH conditions for the 21 days of pod storage while the unfermented samples
enzymatic degradation of polyphenols which may be showed only marginal increases in K content with increas-
present in the cocoa beans in the form of complexes with ing pod storage. Analysis of variance on the data showed
polyvalent cations such as copper, zinc and proteins thus that the K content was significantly (p<0.05) by both
rendering them unavailable. Reduction in these anti- fermentation and increasing pulp preconditioning (Table 4).
nutritional factors therefore might have increased the These high values suggest that potassium is the most
amount of soluble copper in several folds (Nout and abundant mineral in Ghanaian cocoa beans and these might
Motarjemi 1997). have originated from the soil on which the cocoa were
The magnesium content of the cocoa samples were planted.
significantly higher (p<0.05) in unfermented samples than
in the fermented beans (Table 4). Pod storage, however had Physical composition of pulp preconditioned fermented
only marginal influence on cocoa beans with no precise and unfermented cocoa beans
trends in their observation.
Cocoa beans had low sodium content (2.04 to 3.35 mg/ Proportion of cocoa nibs
100 g) and were not significantly (p>0.05) influenced by
fermentation although there were apparent differences The proportion of nibs ranged from 74.1 to 83.5% in the
observed amongst the samples (Tables 3 and 4). On the unfermented and fermented cocoa beans that were not
contrary, increasing pod storage caused general decreases in stored prior to fermentation (Fig. 1a) and these values were
the sodium contents of the samples. ANOVA on the data slightly lower than those (86–90%) reported by Rohan
showed that pod storage had a significant (p<0.05) (1963), Reineccius et al. (1972) and Afoakwa et al. (2008).
influence on the sodium content of the cocoa beans These differences in nib content might have resulted from
(Table 4). Multiple comparison test showed that the beans the harvesting season (whether major or minor) as these
stored for 0 and 14 days prior to fermentation were not have been reported to affect the size of the beans (Rohan
Table 4 ANOVA summary table showing F-ratios for variation in mineral content of pulp pre-conditioned fermented and unfermented cocoa
beans
Variables Ca Cu Na Mg Fe Zn P K
Pod storage (PS) 29.3* 4945.2* 51.1* 82.0* 1341.9* 322.8* 394.3* 1053.7*
Fermentation condition FC) 34.8* 2387.3* 0.1 577.3* 1365.6* 36.1* 84.5* 6180.3*
Interaction (PS x FC) 54.6* 13.8* 118.0* 20.8* 80.8* 322.8* 62.3* 118.5*
* Significant at p<0.05
J Food Sci Technol (November–December 2013) 50(6):1097–1105 1103
have much influence on the proportions. The amount of nib
contained in the bean is of major concern to the cocoa
processor since higher nib content results in higher nib
recovery and fat yield. The apparent increase in weight of
nib reflects a decrease in shell content.
Proportion of shells
Even though the shell provides adequate protection to the nib
from mould and insects infestations, the shell percentage
should be as low as possible (10–14%). This is because the
shell is removed during processing of the cocoa beans and has
very little commercial value to the processor (Rohan 1963;
Reineccius et al. 1972; Wood and Lass 1985; Dand 1997;
Afoakwa et al. 2008). In the unfermented cocoa beans, shell
content for all the pod storage ranged between 25.1 to 12.8%.
By the end of the fermentation, the shell content had decreased
significantly (p<0.05) for the different pod storage days.
Figure 1b shows a sharp decrease from 25.1% to 15.8% shell
content for 0 days pod storage. The considerably high shell
content of all the unfermented samples could be ascribed to
the adhering thick mucilaginous pulp immediately surround-
ing the testa prior to fermentation. Subsequent degradation of
pectin by microbial pectinases during fermentation causes the
liquefaction and drainage of about 10–50% of the pulp
(Ouattara et al. 2008) and this might have accounted for the
Fig. 1 Changes in proportion of cocoa nibs (a), shells (b)and germs relatively lower shell content in the fermented cocoa beans.
(c) in pulp pre-conditioned fermented and unfermented cocoa beans Figure 1b also depicts a decrease in shell content as pod
storage increased with beans stored for 21 days prior to
1963) and the important determining factors are suspected fermentation having the lowest shell content (12.8%), and
to be the amount and distribution of rainfall and tempera- this could be attributed to the reduction in pulp volume by
ture during the development of the pod (Rohan 1963; Wood water evaporation occurring during pod storage (Biehl et al.
and Lass 1985; Dand 1997). High temperatures and lower 1989). This phenomenon could explain the decrease in shell
rainfall might have accounted for the smaller nib proportion content with increasing pod storage. Multiple range test
of the cocoa beans used in the study. Generally, proportion (LSD) showed that the beans stored for the different pod
of nib was slightly higher in the fermented cocoa samples storage days (0, 7, 14 and 21 days) were significantly
than in the unfermented samples (Fig. 1a). different from each other. The cocoa bean shells make up
Pulp preconditioning and fermentation caused significant waste material thus the lower the quantity, the more
increases in weight of the cocoa nibs (Table 5). As desirable it is to the cocoa processor.
illustrated in Fig. 1a, the nib recovery increased with
increasing pod storage days as well as fermentation. The Proportion of germ
amount of pulp on the bean during shell separation would
The proportion of germ for the cocoa beans ranged from 0.73
to 0.75% for all the cocoa beans (Fig. 1c) and this is similar to
Table 5 ANOVA summary table showing f ratios for variation in
physical constituents of pulp pre-conditioned fermented and results reported by Reineccius et al. (1972) (0.77%). Pulp
unfermented cocoa beans preconditioning and fermentation time did not have any
significant effect (p>0.05) on the proportion of germ of the
Variables Cotyledon Shell Germ cotyledons (Table 5). Pods stored for 21 days had their beans
Pod storage (A) 295.7* 281.5* 0.7 germinating and this accounted for the slightly higher
Fermentation time (B) 275.7* 263.7* 0.1 proportion of germs and this observation may be attributed
to pod rotting and the penetration of oxygen during pod
Interaction (A x B) 118.6* 113.5* 0.6
storage (Meyer et al. 1989) hence providing favourable
* Significant at p<0.05 conditions for the germination of the beans.
1104 J Food Sci Technol (November–December 2013) 50(6):1097–1105
Conclusion Crouzillat D, Lerceteau E, Rogers J, Petiard V (1999) Evolution of
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