Effects of traditional starter and the Round‐Koji‐Maker starter on microbial communities and volatile flavours of Chi‐Flavour Baijiu

Summary The mechanised starter‐making has been widely applied to the brewing of Baijiu. However, the effect of mechanical production on microbial flora and volatile flavour compounds of Chi‐Flavour Baijiu was still unknown. This study was to investigate the differences in microbial flora and volatile flavours between the traditional starter Baijiu (BQ) and Round‐Koji‐Maker Starter Baijiu (SQ) during brewing. The results showed that the contents of alcohol, total acidity and organic acid in BQ were significantly higher than those in SQ at the end of fermentation (P < 0.05). The dominant bacterial and fungal genera in SQ and BQ were Lactobacillus and Saccharomyces, respectively. The relative content of Pediococcus and Weissella in BQ was significantly higher than those in SQ in the prophase of fermentation. In respect of volatile flavours, there were 117 kinds of volatile flavours detected in SQ, higher than 90 kinds of those in BQ during the fermentation. The characteristic volatile flavours of Chi‐Flavour Baijiu were all detected with no significant difference between BQ and SQ, and the difference in flavours mainly came from 2‐methoxy‐4‐methylphenol, ethyl decanoate, (E)‐hept‐2‐enal. Lactobacillus was significantly positively correlated with ethyl decanoate and ethyl benzoate in BQ and phenethyl acetate in SQ. In addition, Candida had a strong positive correlation with β‐phenylethanol and ethyl myristicate in BQ and SQ. This study provides an in‐depth analysis of the difference between traditional and mechanical Xiaoqu starters in Baijiu fermentation and theoretical guidance for the standard production and quality improvement of Chi‐Flavour Baijiu.