Microbial community starters affect the profiles of volatile compounds in traditional Chinese Xiaoqu rice wine: Assement via high-throughput sequencing and gas chromatography-ion mobility spectrometry

Abstract

Xiaoqu is a saccharifying and alcohol-producing, flavoring agent used in brewing Chinese rice wine (CRW). We combined high-throughput sequencing with headspace solid-phase microextraction-mass spectrometry-gas phase ion migration spectrometry to identify the microbial communities of four Xiaoqu rice wines collected from Xinhua County, and the flavoring substances of CRWs brewed with them. The most prevalent microorganisms at the genus level were Pediococcus, Enterobacter, Leuconostoc, Weissella, Staphylococcus, Pantoea, Glutamicibacter, Kosakonia, Lactobacillus, Rhizopus, and Mucor. We detected 43 volatile flavoring esters, alcohols, aldehydes, acids, and ketones in the Xiaoqu CRWs. We identified significant positive correlations between Pediococcus/Weissella/Lactobacillus and ethyl butyrate, Pantoea/Kosakonia and 3-methyl-1-butanol/2-methyl-1-propanol, Lactococcus/Streptococcus and ethyl lactate, and Apibacter/Rosenbergiella and ethyl acetate/3-methyl-1-butanol. Relationships between Pediococcus and Lactobacillus/Streptococcus, Rhizopus and Weissella, Mucor, and Leuconostoc, Hydropichia and almost all dominant bacterial genera, as well as Rhizopus and five other fungal genera were synergistic. Carbohydrate, coenzyme, and amino acid metabolism might be the main metabolic processes of dominant bacteria in Xiaoqu. We clarified the dominant microbial community structures of Xinhua Xiaoqu, characterized the flavor compounds in CRW and the relationships between microbiota and flavor. Our findings provide reference data for future flavor-based screens of beneficial bacterial and fungal strains to improve the quality of Xiaoqu CRW.