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 value 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 after-culture HSs, while the ammonium nitrogen increased. In addition, in after-culture old-pit HSs, the values of caproic acid and valeric acid were significantly decreased; in after-culture young-pit HSs, the value of alcohol was significantly decreased, while the value of butyric acid and acetic acid were significantly increased. The bacterial compositions in old/young-pit fresh HSs were similar, in both 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 increased, including many Pit Mud (PM) beneficial anaerobic bacteria. The cluster analysis indicated that culture-or-not had a greater influence on the bacterial communities of HSs, compared with the pit 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 for the bacteria in HSs, which illuminated a new possibility for the 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