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African Journal of Food, Agriculture, Nutrition and Development
Rural Outreach Program
ISSN: 1684-5358 EISSN: 1684-5358
Vol. 15, No. 1, 2015, pp. 9651-9670
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Bioline Code: nd15005
Full paper language: English
Document type: Research Article
Document available free of charge
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African Journal of Food, Agriculture, Nutrition and Development, Vol. 15, No. 1, 2015, pp. 9651-9670
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CHANGES IN SOME BIOCHEMICAL QUALITIES DURING DRYING OF PULP PRE-CONDITIONED AND FERMENTED COCOA ( THEOBROMA CACAO ) BEANS
Afoakwa, E.O.; Kongor, J.E.; Budu, A.S.; Mensah-Brown, H. & Takrama, J.F.
Abstract
Fermentation and drying are critical to the development of flavour precursors that
generate into distinctive chocolate flavour notes during industrial manufacture. These
processes also lead to reduction in acidity and free fatty acids of nibs, which dictates
the levels of bitterness and colour development in chocolates. This study investigated
changes in nib acidity, flavour precursors (sugars concentration and proteins) and free
fatty acids during drying of pulp pre-conditioned and fermented cocoa beans using a 4
x 3 full factorial experimental design with pod storage (0, 3, 7 and 10 days) and drying
time (0, 3 and 6 days) as the principal factors. Non-volatile (titratable) acidity, pH,
sugars (reducing, non-reducing and total sugars), changes in protein content and free
fatty acids of the beans were studied using standard analytical methods. Increasing pod
storage consistently increased pH of the fermented nibs at the end of drying with
consequential decrease in titratable acidity. The pH increased from 4.92 for the freshly
harvested pods to 6.00 for pods stored for 10 days at the end of the drying process.
Similarly, pH of the fermented beans increased with increasing drying time for all pod
storage treatment except for pods stored for 10 days. The pH of fermented beans whose
pods were stored for 3 and 7 days were 5.26 and 5.56 respectively after drying for 7
days. Protein, reducing sugars, non-reducing sugars and total sugars decreased
significantly (p<0.05) with increasing duration of drying at all pod storage periods. Pod
storage and drying significantly (p<0.05) increased the free fatty acids content of the
fermented nibs. The FFAs of the dried beans increased from 0.47% for the unstored
(freshly harvested) pods to 0.55% for pods stored for 3 and 7 days and 0.58% for pods
stored for 10 days. However, FFAs content of all the dried fermented beans were below
the acceptable limits of 1.75% oleic acid equivalent in cocoa butter at all pod storage
periods. Storage of cocoa pod between 3–7 days with 7 days of drying (after 6 days
fermentation) led to considerable reductions in nib acidity, reducing sugars, nonreducing,
total sugars and proteins and acceptable FFA levels.
Keywords
Cacao; pod storage; drying; acidity
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