Microbial Succession During Box and Heap Fermentation of Cocoa beans (Theobroma cocoa) – Impacts on Nutrients and Chocolate Quality

Abstract Cocoa beans (a mixture of 3 varieties) were subjected to heap and box fermentation processes, sun-dried and used to produce chocolate which was compared with chocolate from unfermented cocoa beans. The succession of microorganisms was determined during fermentation. Proximate composition, and phenolic content of samples and the sensory properties of produced chocolate samples were also determined. Bacterial count in both box and heap fermentations decreased with fermentation period. The temperature of the fermenting cocoa beans increased with fermentation period. pH reduced by the 4th day and later increased until day 8.Yeasts and Bacillus species dominated the fermenting mass initially. After 24 h Lactic Acid bacteria emerged, reached their peak at 72 h and decreased significantly after 96 h. Fermentation decreased the fat content by 16.5%, carbohydrate (20.5%), ash (9.3%) and crude fibre content (by 37.4%) but increased the protein content of the samples by 60.3%. Total increase in temperature was 6oC during the 8-day fermentation period. Yeasts, acetic acid bacteria, Bacillus species and lactic acid bacteria were the most predominant organisms responsible for the fermentations. Acetic acid bacteria played a greater role in heap fermentation, than in box fermentation. The fungal count in the box fermentation reduced from the 2nd day to the 4th day (1.47 for day 2, 0.47 for day 4). Fermented cocoa beans dried faster than the unfermented ones. Fermentation decreased the total phenol content (4.59-2.68 mg/g) and increased pH towards alkalinity (pH 5-33- 6.68). Chocolate produced from fermented cocoa beans was more acceptable to consumers than the unfermented sample in terms of sensory properties. Chocolate samples from heap fermentation were more astringent than samples from box fermentation.