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Non-conventional fermentation at laboratory scale of cocoa beans: Using probiotic microorganisms and substitution of mucilage by fruit pulps

Abstract:

In a non-conventional lab-scale fermentation of cocoa beans using probiotic microorganisms and substituting the cocoa pulp for fruit pulp, physicochemical, microbiological and quality parameters were investigated. Two hundred grams of beans were fermented in a controlled environmental chamber (temperature ramp rate of 25°C for 48 h; 35°C for 48 h and 45°C for 48 h; and 65% HR). pH, titratable acid, citric, lactic and acetic acids, as well as sugars and ethanol were measured. A cut test was also performed on the cocoa beans fermented 5 and 6 days. As the fermentation time progressed, citric acid concentration decreased until 0.53 g kg−1, whereas both lactic and acetic acids increased until 0.44 and 16.58 g kg−1, respectively. Sucrose content decreased from 12.26 g kg−1 (in fresh) to 6.54 g kg−1 on the 6th day. Fructose and glucose contents increased in the cotyledons from day five, reaching a maximum concentration of 1.14 and 1.01 g kg−1, respectively, on day six. Yeasts were the main microorganisms during the first 24–48 h (8.4 log CFU g−1), while bacterial counts reached its highest number (7.8 log CFU g−1) on day four. Beans fermented 5 and 6 days resulted in more fermented beans (>81%) and less violet ones (<18.4%) than the control.