Microbial Dynamics Associated with Spontaneous Fermentation of Cocoa (<i>Theobroma cacao</i> L.) in Cameroon and Evaluation of the Quality of Marketable Beans

Abstract

Cocoa fermentation is essential for the production of marketable beans for chocolate manufacturing. It is a microbial process that affects the marketable quality of the beans. The microbial dynamics associated with cocoa fermentation as well as the quality of marketable beans were evaluated in a couple of towns in Cameroon. After plating on selective agar plates, the growth of microflora named yeast, acetic acid bacteria, lactic acid bacteria, bacillus and molds associated with the different fermentations was monitored by enumeration using decimal dilution. The quality of the beans was assessed by the fermentation index, pH and grain size. Cocoa beans from Bafia, Bertoua, Elogbatindi, and Penja were sampled after 0, 24, 48, 72, 96, 120, and 144 hours of spontaneous fermentation. It was found that the order of emergence and the time of appearance of the different microbial genera varied between locations and the fermentations process were generally dominated by yeasts followed by lactic acid bacteria and bacillus witch were found during all the fermentation stages except in Elogbatindi where baccilus appear after 48h. Bean pH decreased from 5.88 ± 0.02 - 6.52 ± 0.01 to 4.34 ± 0.02 - 5.68 ± 0.06. The fermentation index of the beans ranged between 1.00 and 1.40 at the end of the process of fermentation and the seeds obtained had consistent specific weight since the value of their weight were greater than 1. The microbial strains would have a high technological potentiality leading to a good quality of fermented cocoa beans and may be use as starter in improvement program of cocoa beans fermentation process.