Abstract: In this study, the physicochemical properties and bacterial compositions of fresh and statically-cultured Huangshui (HS) from old and young strong-flavor-liquor pits were analyzed. Compared with young-pit fresh HSs, the contents of organic acids, such as butyric acid, caproic acid, valeric acid and acetic acid, and ammonium nitrogen in old-pit fresh HSs were higher. After 5 months of closed static culture, the values of starch, reducing sugar and acidity were decreased in both bit HSs, while the content of ammonium nitrogen was increased. In addition, in old-pit HSs, the contents of caproic acid and valeric acid were significantly decreased; in young-pit HSs, the content of alcohol was significantly decreased, while the contents of butyric acid and acetic acid were significantly increased. The bacterial compositions in old/young-pit fresh HSs were similar to each other, and in both fresh HSs Lactobacillus occupied absolute advantage with abundance of > 95%. After closed static culture, the abundance of Lactobacillus was reduced to 52.5% and 68.55%, respectively, while the abundance of some other aerobic/anaerobic bacteria was increased, including many pit mud (PM)-benefiting anaerobic bacteria. The cluster analysis indicated that static culture had a greater influence on the bacterial communities of HSs as compared with cellar age. The redundancy analysis (RDA) indicated that the reducing sugar showed the highest degree of interpretation of the correlation in RDA analysis, up to 65%. This study preliminarily proved the aging function of closed static culture on the bacteria in HSs, which would make it possible future targeted HS culture to promote the bacterial aging in new PM.

Key words: Chinese strong-flavor Baijiu, physicochemical properties, Huangshui, prokaryotic microbial communities, pit mud aging