Effect of stages of ripening and tray fermentation method on the quality of Cocoa (Theobroma Cacao) beans

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August, 2014
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Tray fermentation method as a cocoa postharvest technology has remained limited in use in Ghanaian cocoa preparation and the need to explore its comprehensive value has become imperative to derive its benefits. The major objective of this study was to assess the effect of different stages of pod ripening on quality of fermented cocoa beans using the tray fermentation method. Three treatments namely, Half ripe, Full ripe and Over ripe were distributed over three sets of trays namely (T 1, T 2 and T 3 ) with each set of tray representing tray replication. Traditional leaves (Heap) method was used as control involving the full ripe stage. The results indicated a significant difference between the over ripe beans and the other three treatments with a percentage mould (1.78%) which was within acceptable maximum level of 4% for grade 2 cocoa. The over ripe beans tray fermented drifted beyond grade 2 with the 6.56% germinated beans content exceeding the 6% upper limit and was rendered substandard. There was also a significant difference between the half ripe tray fermented in terms of slaty (7.45%) which narrowly fell within the acceptable (8%) for grade 2 cocoa, purple (17.33%) was within the grade 1 limit of (20%), and pH (5.77) which was within what could be termed unfermented (5.5-5.8) compared to the other three treatments which were within acceptable limits. The tray fermented over ripe beans also showed a significant difference in terms of pH (4.47) and free fatty acids (0.99%), however, they were within acceptable levels (1.75%) for good quality cocoa. The tray fermentation method was found to be less cost effective than the traditional heap method in the short run. However, the tray method had numerous advantages over the traditional method in the long run.
A thesis submitted to the Department of Horticulture, in partial fulfillment of the requirements for the degree of Master of Philosophy in Post Harvest Technology.