Experimental Evaluation of Mechanical Dehydration of Nigerian Cocoa Beans
A serious problem encountered in commercial cocoa-bean processing is the mouldiness and sprouting which often occur during the "fermentation-sun drying" stages, especially during the rainy season (May-October). An alternative processing technique which employs a forced ventilation, and electrically heated, drying oven has been evaluated, and found suitable for eliminating the sun-drying problem. Several experimental studies and organoleptic tests, using "processed seeds" "unprocessed seeds" and "pod-fermented seeds" (as described in this report) have demonstrated the feasibility of producing acceptable commercial cocoa beans by this technique, at a temperature of about 50oC. Total dehydration period. at 50oC, was about 60 hours, and this could be further reduced to about 7 to 8 hours at higher temperatures (75° to 85°C). However the quality of the products produced at the higher temperatures is somewhat lower than that of 500C. The results indicate a need for further investigation of the fermentation process. dehydration at lower temperatures than 50°C, and the quantitative analysis of the theobromine content of the finished product. The conclusion was that the technique is a feasible proposition which deserves the further investigation and a cost-benefit analysis based on pilot-plant trials.
Mechanical Engineering, University of Nigeria, Nsukka; *presently with the University of Benin, Nigeria