Unveiling the impact of soft wheat proportions on microbial communities and quality attributes of medium-temperature Daqu

<i>Daqu</i> serves as a pivotal fermentation starter in <i>Baijiu</i> and vinegar production, driving complex microbial interactions that critically shape its physicochemical properties and sensory qualities. This study systematically explored the impact of varying soft wheat proportions on the microbial community dynamics, physicochemical parameters, metabolic activities, sensory profiles, and resultant quality attributes of medium-temperature <i>Daqu</i>. The findings demonstrated that increased soft wheat content significantly enhanced sensory attributes but led to a reduction in the diversity and abundance of volatile flavor compounds. Microbial profiling revealed distinct bacterial and fungal community structures, with key taxa exhibiting strong correlations with specific physicochemical and sensory parameters. These results underscore the critical role of raw material composition in modulating the microbial ecosystem and functional attributes of <i>Daqu</i>, offering actionable insights for optimizing starter production and enhancing <i>Baijiu</i> quality.