不同窖龄窖泥产酒发酵前后的理化指标、风味物质含量和细菌菌群结构差异分析

Differences in Physicochemical Indexes,Flavor Substances and Bacterial Community Structure of Pit Mud of Different Ages before and after Fermentation

利用理化检测技术和高通量测序技术对河套酒业不同窖龄窖泥产酒发酵前后的理化指标、风味物质含量及微生物组成做了差异分析并进行相关性分析研究。结果表明,不同窖龄窖泥的理化指标存在显著差异,同一窖龄窖泥产酒发酵前后的理化指标未发生明显变化。乙缩醛、己酸、乳酸乙酯、丁酸乙酯、己酸乙酯等含量在3年窖龄窖泥中相对较高,正丙醇、正丁醇、仲丁醇和丁酸等含量在1年窖龄窖泥中相对较高。两组窖泥产酒发酵前后的风味物质含量也发生了显著变化。两组窖泥测序共获得1039个OTUs分类,每个组都鉴定得到26个细菌门和439个细菌属。得到了不同窖龄窖泥共同的优势菌门和菌属。1年窖龄窖泥发酵前特有的优势细菌属为芽孢杆菌属,发酵后特有的优势细菌属为棒状杆菌属、固氮螺菌属和uncultured_bacterium_f_Lachnospiraceae属;3年窖龄窖泥发酵前特有的优势细菌属为棒状杆菌属、Garciella属、魏斯氏菌属和uncultured_bacterium_c_Gitt-GS-136属,发酵后特有的优势细菌属为固氮螺菌属和uncultured_bacterium_f_Atopobiaceae属。乳酸杆菌属在两个组窖泥中都是绝对优势菌属,且在1年窖龄窖泥中的相对丰度要高于3年窖龄窖泥。经过一个产酒发酵周期,两组窖泥中乳酸杆菌属的相对丰度变化规律一致,都是明显下降,己酸菌属的相对丰度变化规律完全不同。运用Spearman相关性分析分别得到与1年和3年窖龄窖泥理化指标和风味物质显著相关的微生物菌群。本研究为河套人工窖泥的改良和进一步提升原酒品质提供了参考依据。

The differences in physicochemical indexes,flavor substances and microbial composition of the pit mud of different ages before and after fermentation in Hetao Distillery were analyzed by using physicochemical detection technology and high-throughput sequencing technology.The results showed that there were significant differences in the physicochemical indexes of the pit mud of different ages,but there were no significant changes in the physicochemical indexes of the pit mud of the same age before and after fermentation.The contents of acetal,caproic acid,ethyl lactate,ethyl butyrate and ethyl caproate were relatively high in the 3-year pit mud,while the contents of n-propanol,n-butanol,sec-butanol and butyric acid were relatively high in the 1-year pit mud.The contents of flavor substances in the two groups of pit mud changed significantly before and after fermentation.A total of 1039 OTUs were obtained from the two groups of pit mud by high-throughput sequencing,and 26 bacterial phyla and 439 bacterial genera were identified in each group.The common dominant bacterial phyla and genera were obtained from the pit mud of different ages.The dominant bacterial genus was Bacillus in the 1-year pit mud before fermentation,and the dominant bacterial genera were Corynebacterium_1,Azospirillum and uncultured_bacterium_f_Lachnospiraceae after fermentation.The dominant bacterial genera were Corynebacterium_1,Garciella,Weisella and uncultured_bacterium_c_Gitt-GS-136 in the 3-year pit mud before fermentation,and the dominant bacterial genera were Azospirillum and uncultured_bacterium_f_Atopobiaceae after fermentation.Lactobacillus was the absolute dominant genus in both groups,and its relative abundance in the 1-year pit mud was higher than that in the 3-year pit mud.After a fermentation cycle,the relative abundance of Lactobacillus in the two groups of pit mud decreased significantly,but the relative abundance of Caproiciproducens was completely different.Spearman correlation analysis was used to obtain the microbial community significantly correlated with the physicochemical indexes and flavor substances in the 1-year pit mud and the 3-year pit mud,respectively.This study has provided reference for the improvement of the artificial pit mud and the crude liquor in Hetao Distillery.