Effect of Post-Fermentation Technology on Amino Acid Nitrogen Generating during Chinese Rice Wine Brewing

Abstract:

Amino acid nitrogen （AAN） is an important indicator representing the overall level of amino acids and low molecular weight peptides in the Chinese rice wine，which content can affect the quality and flavor of wine. The influence of post-fermentation process parameters to AAN generating were discussed in this work，which included the post-fermentation time and post-fermentation temperature by tracing the dynamic changes of protein content，AAN content and amounts of viable yeast cells， Tricine analysis by SDS-PAGE，and the physicochemical indexes and amino acid composition of fermentation broth. The results showed that the post-fermentation was the main period for AAN producing. The content of AAN in draft rice wine was increased 24.7%，31.7% and 37.6%，respectively when post-fermentation time prolonged from 14 days to 17 days， 20 days and 23 days. Yeast autolysis process offered a significant contribution to AAN at end of post-fermentation. Meanwhile it had positive effect on AAN formation when post-fermentation temperature raised at range of 13 ℃ to 17 ℃. The results implied that AAN was influenced by both activities of protein degradation enzymes and the degree of yeast autolysis when post-fermentation temperature was changed. Furthermore，the work indicated that amino acids are the main composition of nitrogen compounds，which nitrogen content accounted for more than 60% of AAN. This study is aimed to understand the effect of process conditions on the AAN generating，which will benefit the quality improvement of Chinese rice wine.