Determination of postharvest losses in Cocoa (Theobroma cacao) from harvest to the depot

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Cocoa production is a major source of income that sustains the livelihood of millions of farmers and their dependants, contributes significantly to Ghana’s GDP and avenue for foreign exchange earnings. Even though Ghana is a recognized leader in the cocoa industry, its cocoa production faces problems such as postharvest losses which are a major cause of concern to stakeholders. Unfortunately, available information on postharvest losses in cocoa in Ghana is very scanty. This makes it virtually impossible to carry out effective prevention measures. This study was therefore, conducted to assess causes, nature and identify major areas along the production chain where losses occur. The study also sought to examine the effect of fermentation method and number of days of fermentation on the quality and chemical properties of dried cocoa beans. Structured questionnaires were used to collect primary data from farmers to ascertain their perception on extent of postharvest losses on their farms. Field visits were carried out on cocoa farms in the Eastern Region including farms of Cocoa Research Institute of Ghana (CRIG) to qualitatively and quantitatively determine losses along the chain. Responses from the farmers indicated that the major causes of pre-harvest losses in cocoa were capsid attack, black pod attack and rodent infestation. Major postharvest losses occurred at the pod breaking stage and losses were mainly attributed to germinated and caked beans. As to how caked beans affected quality it was observed that they produced higher free fatty acid (8.4%) content and pH (6.8). The study showed that both CRIG and farmers’ farms produced Grade 1 cocoa according to the standards of Quality Control Company (QCC) of Ghana Cocoa Board. Generally, fermenting beans for six days using the heap and basket fermentation methods resulted in Grade 1 cocoa and also produced beans with lower free fatty acids (0.41% and 0.58% respectively). Fermenting beans for six days using tray method produced the best (36.83mg/g) results of polyphenol content in dried beans. The study designed a model that could be used in estimating losses when the quantities of germinated and caked beans are known.
A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirement for the award of Master of Philosophy in Postharvest Philosophy.