Artificial vs. Mechanical Daqu: Comparative Analysis of Physicochemical, Flavor, and Microbial Profiles in Chinese Baijiu Starter Cultures

This study examines the effects of artificial and mechanical production on the physicochemical properties, enzyme activities, flavor components, and microbial diversity of medium-high temperature Daqu, a crucial starter culture for Chinese Baijiu. The research aims to elucidate how these production methods influence the quality of Daqu and to provide technical insights for optimizing industrial production processes. Results demonstrate that artificial Daqu exhibits 0.24% higher reducing sugar content (p < 0.05), 8.3% greater water retention (p < 0.01), and a 0.10-unit increase in acidity (p < 0.05) compared to mechanically produced Daqu. In contrast, mechanically produced Daqu displays a greater liquefaction capability but reduced fermentation capacity. An analysis of volatile flavor compounds reveals that artificially produced Daqu contains a broader spectrum of aroma compounds, particularly esters and alcohols, which are critical for the flavor profile of Baijiu. Microbial analysis demonstrates that artificially produced Daqu possesses a richer diversity of bacterial and fungal communities, with dominant genera such as Aspergillus, Saccharomyces, and Lactobacillus playing a pivotal role in flavor development. These findings offer valuable insights for optimizing Daqu production methods, balancing traditional craftsmanship with modern industrial demands to ensure consistent quality and flavor in Baijiu production.