Cocoa fermentation by selected microorganisms
1994
Jantana Jinda
Yeast and bacteria usually play an important role in cocoa fermentation. Therefore, isolation and identification of microorganisms during cocoa fermentation were studied. Based on 840 isolates, microorganisms identified were those in the genera Acetobacter, Bacillus, Candida, Gluconobacter, Kluveromyces, Lactobacillus, Micrococcus and Saccharomyces. 210 isolates of each yeast, bacteria and acetic acid bacteria were investigated for their efficiencies in alcohol, enzyme pectinase and acetic acid fermentations. The selected alcohol yeasts were KU-Y77, KU-Y79, KU-Y125; pectinolytic microorganisms were KU-Y150, KU-B190 and acetic acid bacteria were KU-A40, KU-A45, KU-A72, KU-A101, KU-A132, KU-A187. All selectes were studied in fermentation. The results of cut test and fermentation index indicated that the mixed culture for use as inoculum in cocoa fermentation consists of Saccharomyces cerevisiae (KU-Y77), Saccharomyces chevalirie (KU-Y150) and Acetobacter aceti (KU-A72) with the amount of inoculum size 1.5, 2.0 and % (by cocoa weight) respectively. The uses of selected microorganisms enable to reduce cocoa fermentation period down from 6 to 4 days with 79-87 % fully fermented beans. The quality of fermented cocoa bean obtained were similar to the 1 st grade standard. The analysis of amino acids and fatty acids in the fermented cocoa bean showed that aspartic acid and glutamic acid were found to reduced considerable in mixed culture fermentation more than in normal fermentation, but increasing acids valued in mixed culture. The theobromine content of both fermented cocoa beans reduced down to standard. The fermented cocoa beans were evaluated by sensory taste in the soft drink form and chocolates. Results showed that the cocoa quality of mixed culture fermented bean as well as referenced cocoa were better than normal fermented bean.
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