Peak-temperature effects of starter culture (Daqu) on microbial community succession and volatile substances in solid-state fermentation (Jiupei) during traditional Chinese special-flavour Baijiu production

Daqu is the natural mixed starter culture for special-flavour Baijiu (the unique famous Baijiu in Jiangxi Province) brewing. Peak-temperature effects of Daqu on chemical compositions, microbial community succession and volatile substances in Jiupei fermented with middle peak-temperature Daqu (MTJP) and Jiupei fermented with high peak-temperature Daqu (HTJP) during special-flavour Baijiu brewing were determined. It was found that ethanol and reducing sugar had significantly (P < 0.05) higher contents in MTJP than HTJP. Peak-temperature of Daqu had a greater impact on the fungal community than the bacterial community in Jiupei. The total content of volatile substances in HTJP was 1.5–3 times of those in MTJP during fermentation. Most esters were positively correlated with Pichia, Lactobacillus and Bacillus genera in HTJP, but positively correlated with Aspergillus, Monascus, Pichia and Lactobacillus genera in MTJP. In a word, middle peak-temperature Daqu (MT Daqu) could enhance the ethanol production through Aspergillus genus with high glucoamylase activity and high peak-temperature Daqu (HT Daqu) could enhance the accumulation of volatile substances through more abundant flavour-producing microorganisms. Our study have provided theoretical basis for the further research on peak-temperature of Daqu effects on the quality of various Chinese Baijiu.