Optimization of alcoholic fermentation of custard apple juice by Saccharomyces cerevisiae using response surface methodology

Abstract

In recent years, custard apple fruit has been applied in food processing with various products. The objective of this study was to valorize a fermented fruit drink from a Vietnamese local custard apple fruit by the alcoholic fermentation of the juice using Saccharomyces cerevisiae. Response surface methodology was used to describe dependency of soluble solid content, inoculum size of yeast and fermentation time on ethanol production during fermentation of custard apple juice by Saccharomyces cerevisiae SLS. The experiments were performed according to the central composite design with total soluble solid content ranging from 16 to 20oBrix, inoculum size of yeast from 1% to 3%, and fermentation time from 42 to 48 h. A quadratic model was developed to correlate the variables to the ethanol yield and sensory score. The results showed that a production of ethanol from the custard apple juice could be achieved reaching up to 5.1% (v/v) at optimum conditions of 19oBrix, 2% yeast and 44-h fermentation time. The model predictions agreed satisfactorily with the experimental values