Isolation And Identification Of The Yeast Strains From Fermented Cocoa Beans

Abstract

Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. The fermentation of cocoa pulp is crucial for developing chocolate flavor precursors. Isolation and identification of some yeasts during cocoa bean fermentation is the first step to create a basis for identifying the mechanism of the process to create chocolate flavor, which is the basis for research and development of regulations. This thesis focuses on the identification of yeast strains that can produce pectinase and cellulase existing in fermented cocoa. The fermented samples, obtained from Trong Duc cacao company limited (Dinh Quan, Dong Nai), were diluted, homogenized and inoculated on Sabouraud dextrose agar medium (SDA) and incubated at 28º C for 3-4 days. Spreading method and disk diffusion test were the main methods to isolate colonies and screen the ability of pectinase and cellulase production of yeast strains. After the isolation, selected colonies were sent to PHUSA Company to identify the name. The identification method used in this study was a combination of morphological identification and analysis of the 28s rRNA coding sequence. Experimental results show that the number of yeast cells varies from 0 to 48x106CFU/g pulp. There were different kinds of genera were characterized including Saccharomyces, Saccharomycodes, Schizosaccharomyces, and Pichia. The result is potential opportunities to improve starter culture for cocoa fermentation. Hopefully, this result will contribute to future studies that are related to cocoa fermentation.