Changing the flavor of black rice wine through three different regional Xiaoqus in China and unraveling its core functional microorganisms
Black rice wine (BRW) is a well-known traditional Chinese rice wine; however, its single variety hinders its development. Accordingly, this study selected three regional Xiaoqu from Sichuan Dazhu (Q1), Jiangxi Yingtan (Q2), and Hubei Fang xian (Q3) as starters to investigate the physicochemical properties, flavor compounds and microbial communities during three BRW brewing. Results indicated that the microbial diversity was Q2>Q3>Q1, and the dominant microbiota in each Xiaoqu varied greatly. Pediococcus, Saccharomycopsis and Wickerhamomyces were the main microorganisms in Q1. Microbes in Q2 distributed relatively even, and Bacillus, Enterobacter, Achromobacter, Pediococcus, unclassified_f__Metschnikowiaceae, Clavispora, and Wickerhamomyces were dominated. In Q3, Pediococcus, Weissella, Saccharomycopsis, Wickerhamomyces and Cyberlindnera were major microbial floras. Redundancy analysis disclosed that temperature, ethanol and total acid were key environmental factors influencing the microbial succession. Altogether 61 flavor substances were identified, 16 of which were common characteristic flavor compounds (odor activity value >0.1). Each BRW possessed unique characteristic flavor compounds. Guaiacol with black rice aroma was first identified as the key characteristic flavor of all BRW. O2PLS and Spearman correlation analysis determined that characteristic flavor compounds of BRW were mainly produced by Saccharomyces cerevisiae, non-Saccharomyces cerevisiae and lactic acid bacteria, with the common core functional strains being Wickerhamomyces and Pediococcus, and their unique core functional strains likely causing unique characteristic flavor. This study could promote the high-quality development of the black rice wine industry.