Effects of the proteins of indica rice and indica waxy rice on the formation of volatiles of sweet rice wine

The proteins in the raw materials affect the formation of flavour during fermentation. Among all the fermentation broth of protein fraction in the study, the rice prolamin and albumin effectively promoted floral, honey and fruity characteristics in fermentation with higher level of beta-phenylethyl alcohol, 2,4-dimethyl-benzaldehyde and ethyl hexadecanoate than those in the fermentation of globulin and glutelin; albumin is with higher level of higher alcohols, but higher alcohols are not good for health because of their acute toxicity and neurotoxic effects. In a further fermentation experiment of addition of prolamin, extra prolamin significantly promoted the formation of aroma volatiles, especially medium and long fatty acid esters and beta-phenylethyl alcohol and its acetate, and the content of beta-phenethyl acetate in sweet rice wine with added prolamin was more than twice that of single sweet rice wine. This study demonstrates that the different rice protein components significantly affect the volatiles generated by microorganism metabolism to impact the flavour of sweet rice wine, and the flavour quality of sweet rice wine can be enhanced by increasing the prolamin content.