Simultaneous saccharification and fermentation of broken rice: an enzymatic extrusion liquefaction pretreatment for Chinese rice wine production

Broken rice, pretreated by enzymatic extrusion liquefaction, was used to produce Chinese rice wine by simultaneous saccharification and fermentation (SSF) process in this study. The study compared the novel process and traditional process for Chinese rice wine fermentation utilizing broken rice and head rice, respectively. With the optimum extrusion parameters (barrel temperature, 98 A degrees C; moisture content, 42 % and amylase concentration, 1 aEuro degrees), 18 % (v/v at 20 A degrees C) alcoholic degree, 37.66 % fermentation recovery and 93.63 % fermentation efficiency were achieved, indicating enzymatic extrusion-processed rice wine from broken rice exhibited much higher fermentation rate and efficiency than traditional-processed rice wine from head rice during SSF. The starch molecule distribution data indicated that the alcoholic degree was related to the oligosaccharides' formation during enzymatic extrusion. Sum of amino acid (AA) in the extrusion-processed wine was 53.7 % higher than that in the traditional one. These results suggest that the enzymatic extrusion pretreatment for broken rice is a feasible and alternative process in the fermentation of Chinese rice wine.