Effect of different fermentation duration and drying methods on the quality of cocoa bean oil
A study was carried out to assess the quality of oil from cocoa seeds (Theobroma cacoa). Fully riped cocoa pods were harvested and the seeds (beans) were fermented for 5-days and 7-days fermentation durations, using 10kg of cocoa beans for each treatment. The fermented beans were afterwards dried by the sun and solar drying methods, under a 2 by 2 factorial in a completely randomized design. Six hundred grams of the dried cocoa beans were milled using a hammer mill and sieved with a 1.18mm standard sieve to obtain fine particle size. Using the Soxhlet’s extraction procedure, the oil was extracted. Afterwards, the yield and other quality parameters including acid value, relative density, saponification value, peroxide value, iodine value, refractive index and free fatty acid content, were assessed. The oil yield range (24.10-29.00%) for the interactive effect was low, compared to oil rich seeds used as commercial sources of oil. The study revealed that, though the cocoa bean oil produced from both 5-day and 7-day fermentation durations all had acid values and free fatty acid percentages with significant differences between them but they were all within the range for consumption (0-10). On the other hand, oil produced from 7-day fermentation duration of cocoa beans had the least peroxide value. Though the acid values and free fatty acid contents of the oils produced from the different drying methods were numerically different between the two drying methods, they were not significantly different. Furthermore, the acid values and free fatty acid contents were all within the acceptable range for consumption From the interactive effects, it was also determined that 7-day fermentation duration and solar drying produced the best quality oil among all the interactive effects.
A thesis submitted to the School of Research and Graduate Studies, Kwame Nkrumah University of Science and Technology, in partial fulfilment of the requirement for the award of the degree Master of Philisophy (M.Phil.) in Postharvest Technology,2016