不同颜色酱香型大曲微生物群落结构及功能比较

Comparative analysis of microbial community structure and function in Jiangxiang Daqu with different colors

由于固态发酵的异质性,导致酱香型大曲常常出现黑色、褐色及黄色3种不同类型大曲,为了解其质量差异,对不同颜色大曲的微生物群落结构、酶活力和挥发性风味物质进行分析,并对其进行基因功能预测。基于微生物多样性组成,利用线性判别分析研究了3种颜色大曲微生物差异,通过PICRUSt2对其功能差异进行了预测,并基于相关性分析研究了微生物与酶活力和风味之间的关系,同时,比较了理化指标差异。结果表明,黄曲的特征微生物为嗜糖假单胞菌属(Pelomonas)、副球菌属(Paracoccus)、螯台球菌属(Chelatococcus)、嗜热真菌属(Thermomyces)和unclassified_Nectriaceae,褐曲的特征微生物为被孢霉属(Mortierella),黑曲的特征微生物为嗜热子囊菌属(Thermoascus)和镰刀菌属(Fusarium);3种颜色的大曲微生物的功能差异主要体现在碳水化合物代谢和氨基酸代谢;糖假单胞菌属、副球菌属和螯台球菌属主要影响苯甲醇、苯乙醇、苯酚和邻苯二甲醚的合成;被孢霉属与十六酸乙酯和酯化力呈正相关;嗜热子囊菌属和镰刀菌属是引起大曲高酯化力的关键微生物,黑曲的淀粉含量显著低于黄曲和褐曲,而水分、总酸和还原糖含量均高于黄曲和褐曲。该研究阐明了3种颜色大曲质量差异,其结果可为评价酱香型大曲质量提供参考。

Due to the heterogeneity of solid-state fermentation,three different types of black,brown and yellow Daqu often appear in Jiangxiang Daqu.In order to understand the quality differences,the microbial community structure,enzyme activity,and volatile flavor substances of Daqu with different colors were analyzed,and their gene function was predicted.Based on the composition of microbial diversity,the microbial differences of three kinds of color Daqu were studied by linear discriminant analysis.The functional differences were predicted by PICRUSt2,and the relationship between microorganisms and enzyme activity,microorganisms and flavor were studied based on correlation analysis.At the same time,the differences of physical and chemical indexes were compared.The results showed that the characteristic microorganisms of yellow Daqu were Pelomonas,Paracoccus,Chelatococcus,Thermomyces,and unclassified_Nectriaceae,the characteristic microorganism of brown Daqu was Mortierella,and the characteristic microorganisms of black Daqu were Thermoascus and Fusarium.The functional differences of Daqu microorganisms with three colors were mainly reflected in carbohydrate metabolism and amino acid metabolism.The genus Pelomonas,Paracoccus,and Chelatococcus mainly affected the synthesis of benzyl alcohol,phenethyl alcohol,phenol,and 1,2-dimethoxybenzene.Mortierella was positively correlated with ethyl hexadecanoate and esterification activity.Thermoascus and Fusarium were the key microorganisms causing high esterification activity of Daqu.The starch content of black Daqu was significantly lower than that of yellow Daqu and brown Daqu,while the contents of moisture,total acid,and reducing sugar were higher than those of yellow Daqu and brown Daqu.This study clarified the quality differences of Daqu in three colors,and the results could provide reference for evaluating the quality of Jiangxiang Daqu.