Study On Microbial Diversity And Volatile Flavor Compounds During The Fermentation Of Chestnut Glutinous Rice Wine

Chestnuts have rich nutritional value.Developing a brewing wine made from chestnuts and glutinous rice can unleash the nutritional benefits of the raw materials,enhance the added value and economic benefits of chestnuts.This article screened the optimal fermentation starter for chestnut glutinous rice wine,studied the microbial community succession and changes in volatile flavor substances during the fermentation process of chestnut glutinous rice wine,and determined the correlation between the two.The main research results are:(1)Firstly,by analyzing the physicochemical indicators of rice wine koji from 9different regions,it was determined that ZJK1 had the highest saccharifying enzyme activity and amylase activity.Secondly,through the high-throughput sequencing technology to analyze the microbial diversity of each distiller’s yeast,the results showed that the richness and diversity of the microbial community of distiller’s yeast ZJK1 were the highest.Finally,based on the sensory evaluation of chestnut glutinous rice wine brewed with each koji,it was determined that ZJK1 had the highest sensory score for chestnut glutinous rice wine brewed with each koji.Therefore,ZJK1 was determined as the best brewing koji for chestnut glutinous rice wine.(2)The microbial community diversity and community structure during the fermentation of Chinese chestnut glutinous rice wine were analyzed by high-throughput sequencing technology;β Diversity analysis shows that the succession of bacterial communities during the fermentation process can be divided into three stages,while fungi can be divided into two stages.The analysis of microbial community structure during the fermentation process shows that there are 4bacterial dominant phyla and 1 fungal dominant phyla;There are 8 bacterial genera with relative abundance ≥ 1%,and 1 fungal genus;There are 8 fungal genera with relative abundance ≥ 0.01%.(3)The volatile flavor compounds in chestnut glutinous rice wine fermentation process were analyzed using headspace solid-phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC-MS),and a total of 80 volatile compounds were detected.Alcohols(13.07-60.61%)and esters(3.74-22%)were the main volatile flavor compounds in the fermentation process,with phenylethanol being the main alcohol(1.80-60.49%),Ethyl decanoate(1.12-9.18%)is the main ester substance,and there are a total of 9 volatile substances that have been present and high in content during the fermentation process of chestnut glutinous rice wine.(4)Based on Spearman correlation analysis,a correlation analysis was conducted on the dominant microbial genera in the fermentation process of chestnut glutinous rice wine.The results showed that there were 19 significant positive correlations(| r |>0.6,p<0.05)and 9 significant negative correlations(| r |>0.6,p<0.05)between the microbial genera,among which Saccharomyces was significantly negatively correlated with all fungi(| r |>0.6,p<0.05).It was found that the dominant microbial genera and physicochemical properties during the fermentation process of chestnut glutinous rice wine were significantly influenced by total acids and p H.The association between microbial communities and volatile substances during the fermentation process of chestnut glutinous rice wine showed that the genus Oceanobacillus,unclassified Bacterillae,and Rhodococcus were the bacterial genera that determined the main volatile flavor substances of chestnut glutinous rice wine;Saccharomyces is a fungal genus that determines the main volatile flavor compounds of chestnut glutinous rice wine.