Mechanism Underlying the Quality Improvement of Fuhexiang Baijiu by Wheat Raw Materials: Insights From Fermentation Microenvironment and Microbial Metabolic Network

ABSTRACT The composition of raw materials forms the foundational basis for shaping the flavor micro‐ecosystem of Baijiu. To elucidate the underlying mechanisms by which wheat varieties influence the flavor formation of Fuhexiang Baijiu, this study employed Lüzhèng wheat and local wheat with distinct compositional profiles as models under a TTMP‐fortified bran‐based Qu system. We systematically investigated the complete chain of dynamic changes from raw material properties, microenvironment, microbial communities, to flavor metabolites. Results confirmed that the high‐protein (12.63%), high fat (1.24%), and low fiber (2.20%) characteristics of Lüzhèng wheat provide a more balanced nutritional framework for the fermentation system. This advantage was activated during pit fermentation, translating into more efficient microenvironment regulation, as evidenced by intensified starch metabolism (degradation by 12.29%), significant acidity accumulation (increase by 32.82%), and robust hydrolytic enzyme activities in the early stage. The distinct microenvironment further shaped the structure and function of the microbial community. Key functional genera, including Lactobacillus , Acetobacter , and Monascus , were significantly enriched in the fermented grains of Lüzhèng wheat (e.g., Monascus reached 4.5% relative abundance on day 12), forming a more resilient community succession pattern. Integrated multi‐omics correlation analysis revealed that in the Lüzhèng wheat system, a metabolic network—initiated by raw material composition, driven by specific microenvironments, and mediated by functional microbiota—was effectively established, leading to efficient synthesis of key flavor compounds such as TTMP, ethyl esters, and organic acids. Elements within this network (physicochemical parameters–microorganisms–flavor compounds) exhibited highly synergistic and positive feedback relationships. Ultimately, this optimized metabolic network directly enhanced the quality of the final product, with the sensory score of raw liquor from Lüzhèng wheat being significantly higher by 1.20 points. This study not only comprehensively reveals the cascading mechanism of “raw material composition → fermentation microenvironment → microbial community → flavor metabolic network,” but also provides a theoretical basis for selecting high‐quality raw materials and optimizing process parameters for Fuhexiang Baijiu.