新老窖池黄水的差异性及静置培养对其影响

Differences between Huangshui from Old and Young Mud Pits of Chinese Strong-Flavor Liquor and Effect of Static Culture on It

分析浓香型新老窖池新鲜黄水封闭静置培养前后的理化性质和菌群组成。新老窖池新鲜黄水相比,后者丁酸、己酸、戊酸、乙酸等有机酸和铵态氮的含量较高。新老窖池黄水经过5个月的封闭静置培养,淀粉、还原糖和酸度值降低,而铵态氮增加;此外,老窖池黄水己酸和戊酸值降低;新窖池黄水的乙醇值显著降低,同时丁酸和乙酸的值显著增加。新老窖池新鲜黄水中乳酸杆菌(Lactobacillus)均占绝对优势(>95%),封闭静置培养后,Lactobacillus分别降低至68.55%和52.5%,同时其他菌属的丰度增加,其中包括很多对窖泥老熟有益的厌氧菌。聚类分析表明:与窖龄相比,是否静置培养对黄水菌群的影响更大。冗余分析表明:还原糖与菌群结构的相关性最强,其解释度高达65%。本研究证明了封闭静置培养对黄水菌群的老熟作用,为将来定向培养黄水以促进新窖泥的老熟提供了可能性。

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.