Flavor Profile of Chinese Liquor Is Altered by Interactions of Intrinsic and Extrinsic Microbes

The flavor profile of Chinese liquor is the result of the metabolic activity of its microbial community. Given the importance of the microbial interaction, a novel way to control the liquor's flavor is by regulating the composition of the community. In this study, we efficiently improved the liquor's flavor by perturbing the intrinsic microbial metabolism with extrinsic microbes. We first constructed a basic microbial group (intrinsic) containingSaccharomyces cerevisiae ,Wickerhamomyces anomalus , andIssatchenkia orientalis and added special flavor producers (extrinsic),Saccharomyces uvarum andSaccharomyces servazzii , to this intrinsic group. Upon the addition of the extrinsic microbes, the maximum specific growth rates ofS. cerevisiae andI. orientalis increased from 6.19 to 43.28/day and from 1.15 to 14.32/day, respectively, but that ofW. anomalus changed from 1.00 to 0.96/day. In addition, most volatile compounds known to be produced by the extrinsic strains were not produced. However, more esters, alcohols, and acids were produced byS. cerevisiae andI. orientalis . Six compounds were significantly different by random forest analysis after perturbation. Among them, increases in ethyl hexanoate, isobutanol, and 3-methylbutyric acid were correlated withS. cerevisiae andI. orientalis , and a decrease in geranyl acetone was correlated withW. anomalus . Variations in ethyl acetate and 2-phenylethanol might be due to the varied activity ofW. anomalus andS. cerevisiae . This work showed the effect of the interaction between the intrinsic and extrinsic microbes on liquor flavor, which would be beneficial for improving the quality of Chinese liquor.