Design and optimization of an efficient enzymatic extrusion pretreatment for Chinese rice wine fermentation

Chinese rice wine, produced by simultaneous saccharification and fermentation (SSF), has an uneconomic, time-consuming and environment-unfriendly pretreatment. In this study, an enzymatic extrusion pretreatment was applied to manufacture Chinese rice wine. Response surface methodology (RSM) was used to investigate the effect of process parameters namely barrel temperature (BT), moisture content (MC), and α-amylase concentration (AC) on the alcoholic degree of rice wine. Statistical analyses revealed that the experimental data were adequately fitted into the second-order polynomial model with a high coefficient of determination (R2) of 0.97. It also showed that MC had the most significant effect on the alcoholic degree among the three parameters. Starch molecular weight distribution data indicated that the alcoholic degree was closely related to the oligosaccharides forming during enzymatic extrusion. Total of amino acids (AA) in the extrusion-processed wine was 41% higher than that in the traditional one. These results suggest that the enzymatic extrusion pretreatment, instead of the traditional one, is feasible for Chinese rice wine production.