Seasonality shapes the microbiota and metabolome of strong-flavor Baijiu during fermentation and affects its flavor characteristics

• Published in: Food bioscience Vol. 62; p. 105534
• Main Authors: Chai, Li-Juan, Zhang, Jing-Yi, Gao, Tao, Zhang, Long-Yun, Zhang, Xiao-Juan, Lu, Zhen-Ming, Shi, Jin-Song, Chen, Xiang, Xu, Zheng-Hong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2024
• Subjects: Environmental factors; Fermented grains; Flavor compounds; Microbial community; Seasonal variations; Strong-flavor baijiu; Seasonal variations; Strong-flavor baijiu; Environmental factors; Flavor compounds; Microbial community; Fermented grains
• ISSN: 2212-4292
• DOI: 10.1016/j.fbio.2024.105534

The microbial community and product flavor of fermented foods are subject to seasonal environmental fluctuations due to open production environment. However, research on the impact of external environmental changes caused by seasonal shifts on brewing is limited. Here, we studied changes in physicochemical indicators and flavor compounds of fermented grains during Baijiu fermentation in four seasons, as well as the succession and assembly of microbial communities. The temperature throughout fermentation was highest in summer, followed by spring and autumn, and lowest in winter. Winter had slower rates of moisture growth, total acidity accumulation, and sugar consumption than the other seasons. At the end of fermentation, the highest total organic acid content was identified in summer, and the lowest level of volatile compounds was found in winter. We found significant differences in microbial community structure across different seasons. Meanwhile, compared to fungal community, the succession of bacterial community was more susceptible to brewing environment, with reducing sugar being the main driving factor in the early stage and total acidity, organic acids, and moisture being the main driving factors in the late stage. The microbial co-occurrence networks in autumn and winter were more complex than those in spring and summer. Furthermore, brewing in the spring and summer promoted the accumulation of acids in Baijiu, esters in summer, ethyl esters in autumn, and aldehydes and ketones in winter. This study offers a fresh perspective on the microbial brewing mechanism of Baijiu by exploring the seasonal variations of microbiota and metabolome. •Fungal community structure across four seasons varied more than that of bacteria.•Bacterial community was more responsive to brewing environment than fungal community.•Microbial network in spring and summer was simpler and more modular.•More bacterial ASVs were positively correlated with volatiles than fungal ASVs.•Flavor compounds in raw Baijiu varied dramatically over four seasons.