Effect of fermentation conditions on rice wine - a comparative study using baker's yeast and pure strain

Abstract

Rice wine, an ancient fermented drink derived mainly from rice starch, was the focus of this study, where fermentation conditions were optimised using both baker's yeast and a pure strain during 7 fermentation days. The optimization process employed a response surface method (RSM) with central composite design to evaluate the impact of varying levels of inoculum concentration (1-5%), sugar content (0-40%), and water content (30-70%) on key response variables. These included total score, alcohol content, pH levels, TSS (total soluble solids), wine yield, and total sugar, exploring their interactive effects. The optimal fermentation conditions involved an inoculum concentration of 3.41%, a sugar content of 34.68%, water content of 60.95%. Desirable outcomes were achieved as 14.20 total score, 6.09% alcohol content, 3.17 pH, 15.26 B0 TSS, 6.41% total sugar, and 52.05% wine yield with a desirability value of 0.98 for rice wine using baker's yeast. Similarly, pure strain were used at an inoculum concentration of 3.36% sugar content of 36.49% water content of 68.71% and responses were achieved as 12.84 total score, 3.94% alcohol content, 3.14 pH, 15.24 B0, TSS, 6.22% total sugar and 51.33% wine yield with a desirability value of 0.82.