Effects Of Highland Barley On The Succession Of Microbial Community During Highland Barley Baijiu Fermentation

The raw materials have an important influence on the metabolism of the microbial community and product quality of the fermented food,but it is still unclear how the raw materials affects the microbial community and regulate the flavor information.In this study,the highland barley baijiu system is used as a research object to reveal the key factors affecting the succession of microbial community during the fermentation process of highland barley baijiu and the mechanism of barley raw material driving the microbial community,which will provide a theoretical basis for the production of highland barley baijiu with different raw material.The main results of this study are as follows:(1)To reveal flavor-related microbiota during the fermentation process of highland barley baijiu,this study analyzed the microbial community during the fermentation process of different highland barley by high-throughput sequencing.We found that the dominant genus were Pichia,Komagataella,Aspergillus,Saccharomyces,Candida,Hyphopichia,Wickerhamomyces,Hanseniaspora,Geotrichum,Lactobacillus,Weissella,Pantoea,Acinetobacter,Staphylococcus,Pediococcus,Fructobacillus and Bacillus?HS-SPME-GC-MS method was used to analyze the flavors in different fermented grains.More alcohol compounds and carbonyl compounds were detected in fermented grains dulihuang.But more ester compounds were detected in fermented grains heilaoya.Based on the Spearman correlation between dominant genus and flavors,Aspergillus,Komagataella,Lactobacillus,Pichia,Saccharomyces and Weissella were identified the flavor-related microbiota.(2)In order to reveal the driving mechanism of the highland barley on the flavor-related microbiota,the Mantel test of physicochemical factors and microbial community was used to find reducing sugar(heilaoya: p = 0.001;dulihuang: p = 0.006)driven the succession of microbial community in different fermented grains.Through RDA analysis and correlation analysis,it was found that glucose and fructose in fermented grains drove the succession of flavor-related microbiota.And glucose(P = 0.0226)and fructose(P = 0.0168)presented the most significant correlations with Pichia and Komagataella,respectively.The results of monoculture and co-culture experiments showed that K.phaffii QK2 grew better in heilaoya with more fructose,whereas P.fermentans PF grew better in dulihuang with more glucose.These results showed that the glucose and fructose of highland barley drove the succession of flavor-related microbiota,thus affecting the metabolism of flavors.(3)It is unclear about the sources of glucose and fructose in fermented grains dulihuang and heilaoya.This study analyzed the metabolic characteristics of glucose and fructose and the glucoamylase activity of Aspergillus niger M1 and Aspergillus oryzae M2 in dulihuang and heilaoya.The results showed Aspergillus niger M1 and Aspergillus oryzae M2 had stronger fructose metabolism activity in heilaoya,and had stronger glucose metabolism activity in dulihuang.Compared with other traditional brewing materials,Aspergillus niger M1 and Aspergillus oryzae M2 had stronger glucoamylase activity in highland barley.Aspergillus niger M1 had the highest glucoamylase activity(177.82 U/g)in dulihuang while Aspergillus oryzae M2 had the highest glucoamylase activity(697.50 U/g)in heilaoya.These results revealed that dulihuang and heilaoya have an important influence on the metabolism activity of glucose and fructose and the glucoamylase activity of the saccharification molds.