Assessment of wheat Qu fermented at medium and high temperatures: Effects of Bupleurum addition on fermentation characteristics, volatile profiles, and microbial communities.

The quality of wheat Qu significantly influences rice wine production. However, quality control is often challenging due to variations in raw materials, preparation methods, and climatic conditions. Nevertheless, the impact of traditional northern Chinese craftsmanship techniques on the quality of wheat Qu remains largely unexplored, and addressing this gap is crucial for standardizing fermentation processes and optimizing rice wine production. In this study, we investigated the impact of traditional northern Chinese wheat Qu craftsmanship techniques on product quality by comparing the fermentation characteristics, volatile profiles, and microbiomes of three types of wheat Qu (medium-temperature wheat Qu without Bupleurum; medium-temperature wheat Qu with Bupleurum; and high-temperature wheat Qu with Bupleurum). We found that Bupleurum addition and thermal treatment can alter the microbial communities enriched in starters, enhancing fermentation performance and aroma characteristics. Additionally, we identified key aroma compounds and microbial biomarkers that could distinguish among different types of wheat Qu. Finally, statistical analyses and functional prediction assessments suggested that fungi likely drive microbial succession and metabolism in wheat Qu. These findings enable the development of strategies for optimizing wheat Qu production.