Analysis Of The Microbial Community Structure And The Correlation With Flavor Substances During Qingshuang Type Chinese Rice Wine Brewing

Chinese rice wine is our national specialty. Since traditional rice wine belongs to multi- microorganisms mixed fermentation way, the fermentation way gave it a mellow taste with a slight acidity, and also the regional consumption was obvious. Q ingshuang type Chinese wine was fermented on the basis of traditional Chinese rice wine brewing technology, and the fermentation process was modified by adding enzymes, reducing the dosage of raw wheat Qu. Q ingshuang type C hinese rice wine cater to the consumers who pursue the concept of low alcohol contents and health. However, as a new technology wine, the research of qingshuang type rice wine fermentation process was still in infancy. Although the amount of added raw wheat Qu decreased, the microbial community structure, the formation of flavor substances, and the relationships between microbes and flavor substances in the process of fermentation had not been resolved yet. Therefore, in this study the High throughput sequencing technology was used to analyze the microbial community structure, and to explore the evolving law of microbial community during the fermentation process, the flavor characteristics, and finally the relationships between microorganisms and flavor substances. This research had the vital significance to improve the quality and direct the prod uction of Chinese rice wine.The main results were as follows:(1) Total concentrations of amino acids, organic acids and volatile substances had a growing trend during the fermentation time. The greatest increased amino acids contained alanine, arginine and glutamic. Lactic acid and acetic acid were the main organic acids in rice wine. 49 volatile flavor substances were detected during the fermentation process by HS-SPME-GC/MS, among the substances higher alcohol and esters had a larger proportion than aldehydes.(2) The HTS was used to identify the microorganisms of rice wine, and the results of bacterial diversity identified showed the diversity in fermented mashes were much higher than that in wheat Qu. The major bacteria phyla in samples were Proteobacteria(44.59%), Firmicutes(32.23%), Actinobacteria(9.51%) and Cyanobacteria(3.48%). The major bacteria genera in fermented mashes were Bacillus(7.61%), Pseudomonas(5.38%), Lactococcus(4.81%), Weissella(3.95%), Staphylococcus(2.97%), Saccharopolyspora(2.30%), Lactobacillus(2.10%), Acinetobacter(1.31%), Leuconostoc(0.93%), Citrobacter(0.83%), Thermoactinomyces(0.53%) and Enterococcus(0.36%). However the major bacteria genera in wheat Q u were Bacillus(18.59%) and Staphylococcus(1.49%), so the Bacillus was the dominant bacteria genus in qingshuang type C hinese rice brewing. The fungal diversity in fermented mashes was less than that in wheat Q u. The major fungal phyla in wheat Qu and fermented mashes was Ascomycota, and relative abundances of Ascomycota in all samples had reached 80%. There were 16 fungal genera identified in wheat Qu, and the major genera were Aspergillus(72.90%), Alternaria(6.02%), Thermomyces(2.38%), Fusarium(1.70%) and Epicoccum(1.44%), Aspergillus continued to increase with the fermentation periods, and the relative abundances of Aspergillus increased from 0 d(95.09%) to 24 d(99.67%), there had a higher relative abundance in different time and it was the dominant fungal genera in qingshuang type Chinese rice brewing process.(3) PLSR was used to analyze the correlations between microorganisms and flavor substances. Acetobacter, Lactobacillus, Paenibacillus, Bacillus and Saccharopolyspora had correlations with organic acids; Lactobacillus played main role in the secretion of amino acids along with Candida, Aspergillus had correlations with isobutyl alcohol, isoamyl alcohol, ethyl acetate, Saccharopolyspora had correlations with phenyl ethyl acetate and butyl acetate, Bacillus had closer correlations with heptanoic acid ethyl ester, etc. The correlation analysis results showed that microorganisms had correlations wit h some kind of flavor substance, and also with a variety of flavor substances, there were complex relationships between microorganisms and flavor substances.