Difference analysis of Sichuan strong-flavor Baijiu Daqu in typical producing areas

The difference of Daqu producing areas has a strong contribution to the "regional style" of Baijiu. In this study, the differences of physicochemical properties, microbial community structure and volatile flavor components of Daqu in 3 main production areas of Sichuan strong-flavor (Nongxiangxing) Baijiu (Yibin Q1, Luzhou Q2, Chengdu Q3) were compared. The results showed that the physicochemical properties of Daqu in different production areas were significantly different. The results of Illumina high-throughput sequencing showed that the dominant fungal genera of Q1-Q3 were Thermoascus (56.51%, 74.71% and 69.11%), the dominant bacterial genera were different, Pantoea (62.27%) was dominant in Q1, Thermoactinomyces (70.84%) was dominant in Q2, and Weissella (42.50%) was dominant in Q3. The volatile flavor compounds compositions analyzed by GC-MS showed that the esters were the main volatile flavor compounds in three samples, but the composition was significantly different, with obvious "appellation characteristics". Correlation analysis showed that Rhizomucor were significantly positively correlated with saccharification and esterification power (P<0.05), while Aspergillus and Rhizopus were positively correlated with ester substances, the fermentation power and more volatile flavor substances were closely related to the yeasts (mainly Pichia and Wickerhamomyces). These research results would provide certain data support for preliminary clarification of the typical production areas characteristics of Sichuan strong-flavor Daqu, and help the construction of Sichuan Baijiu "password producing area".