Correlation analysis of microbial groups and sensory quality in the fourth round of the stacked fermentation of sauce-flavor liquor

Stacked fermentation is the process of utilizing microorganisms in the environment and further enriching their population in Jiupei. However, the composition of microbial communities in the different layers of Jiupei and their relationship with sensory quality requires more clarity. This study analyzed the microbial composition of the different layers of Jiupei in the fourth round of stacked fermentation using high-throughput sequencing technology. Physicochemical properties and sensory qualities were measured; the correlation between the observed microorganisms and sensory quality was further analyzed. The results showed that there were significant differences in acidity, moisture, starch, reducing sugar, and protein content across the different layers of the Jiupei (P < 0.05). The flavor substances in the entire Jiupei dump primarily included organic sulfides, terpenes, and ethanol, and umami was the most dominant taste indicator. Significant differences in microbial community structure were observed across the layers of the Jiupei, with the main bacterial genera being Thermoactinomyces (63.95%), and Bacillus (11.77%). Meanwhile, the main fungal genera identified were Pichia (28.37%), Saccharomyces (24.42%), and Byssochlamys (17.01%). The correlation between the microorganisms and the sensory indexes in Jiupei was found to be significant (P < 0.05); the presence of the bacterial genera Bacillus and Thermoactinomyces and the fungal genera Saccharomyces, Byssochlamys, and Zygosaccharomyces was found to be related to the sensory quality of Jiupei. This study provides insights into the role of microorganisms in the fourth round of liquor fermentation and provides a theoretical reference for the subsequent optimization of sauce-flavor liquor quality.