Effects of two different drying mats at different loading densities on the physical and chemical qualities of cocoa beans

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Sun drying produces the best quality cocoa beans if it is properly done, but more often than not bad weather conditions make sun drying inefficient and produce beans of inconsistent quality. Various drying methods have been adopted in a bid to arrive at beans that meet the aroma and flavor characteristics required by chocolate manufacturers. This research work was, therefore, set up to compare the drying potentials of the SNSpac drying mat and the raffia drying mat at three different loading densities, ie. 3kg, 6kg, and 9kg, and to assess their impact on the physical and chemical qualities of the dried beans. In terms of drying time, there were significant differences among all the treatments indicating that the type of mat used and the various loading densities all affected the rate of drying of the beans. Fastest drying rates were observed in the 3kg loadings on both mats, but upon chemical analysis it was found that beans from these treatments contained high acidities and free fatty acid levels that were higher than the permissible levels recommended by the Quality Control Company of the Ghana Cocoa Board (QCC). The cut test analysis showed that the treatments on the raffia mat resulted in higher percentage brown beans and lower percentage purple beans, but these were not significantly different from the scores obtained from the SNSpac. Surface moulding was observed in the medium and high (6kg and 9kg) loading on the SNSpac mat, while slight surface moulding occurred only on the high (9kg) loading on the raffia mat. Significant differences in Polyphenol concentrations were due to the different loading densities and not the drying mats. However, the range of total Polyphenol concentration in all the treatments fell within the levels recommended by the QCC. Overall quality assessment showed that the 9kg treatment on raffia mat produced reasonably good quality beans as compared to the other loadings.
A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi , in partial fulfillment of the requirements for the award of the degree of Master of Philosophy (M.Phil.) in Post Harvest Technology, 2014