Abstract:
As a crucial fermenting and saccharifying agent for light-flavor Baijiu, low-temperature Daqu provides abundant microorganisms, enzyme systems, and flavor precursor substances during the brewing process, influencing the liquor's style and yield. To investigate the quality differences of low-temperature Daqu from different regions, this study employed PacBio SMRT sequencing, electronic nose, electronic tongue, and physicochemical analysis to conduct a comprehensive analysis of low-temperature Daqu samples collected from Xiangyang and Fenyang City. Results revealed that there were significant differences in microbial community diversity and structure between the two regions (
P<0.05). Specifically, species such as
Lactiplantibacillus plantarum and
Saccharomycopsis fibuligera were significantly enriched in the Xiangyang low-temperature Daqu samples (
P<0.05), while species such as
Bacillus licheniformis and
Issatchenkia orientalis were significantly enriched in the Fenyang low-temperature Daqu samples (
P<0.05). Xiangyang low-temperature Daqu was rich in aromatic compounds with a more prominent richness (
P<0.05), while Fenyang low-temperature Daqu contained higher concentrations of alcohols and aldehydes/ketones, with more prominent sourness, bitterness, and astringency (
P<0.05). Xiangyang low-temperature Daqu samples had significantly higher water activity, bound water content, liquefying power, acidity, ash content, and starch content (
P<0.05), while Fenyang low-temperature Daqu samples had significantly higher qu-skin hardness, qu-core hardness, water content, immobilized water content, liquor-producing power, fermentation power, esterifying power, saccharification power, and protein content (
P<0.05). There was a significant correlation between the dominant species in Daqu and sensory and physicochemical indicators. It could be seen that there were significant differences in microbial community structure and quality indicators between Fenyang and Xiangyang low-temperature Daqu. These findings provide empirical data support for improving the quality of light-flavor Baijiu.