Microbial enzymes: the bridge between <i>Daqu</i> flavor and microbial communities
Zelong Zhong, Tianyi Liu, Kan He, Min Zhong, Xiaoxue Chen, Yansong Xue, Bei‐Zhong Han, Diqiang Wang, Jun Liu
Abstract
Baijiu <i>Daqu</i>, a traditional component in the Baijiu brewing process, serves as both a 'saccharifying fermenting agent' and an 'aroma-producing catalyst', embodying a rich historical legacy. <i>Daqu</i> offers a diverse microorganism environment that is crucial for the fermentation of Baijiu. The distinctive flavor profile, a key attribute of Baijiu, is intricately linked to the microflora present in <i>Daqu</i>. To date, research on <i>Daqu</i> has primarily concentrated on the diversity of microbial communities, microbial interactions, flavor characteristics, and biochemical properties. The functional enzyme system in <i>Daqu</i> serves as a crucial link connecting the flavor of Baijiu with the microbial community of <i>Daqu</i>. However, reviews that particularly focus on the role of enzymes in determining the quality of <i>Daqu</i> have not yet been reported. Thus, here the types and production processes of <i>Daqu</i> are initially summarized. Then, the pathways involved in the production of the major flavor substances in <i>Daqu</i> are elucidated, as well as the role and contribution of different functional enzymes in the formation of <i>Daqu</i> flavor. Finally, the current technologies for improving <i>Daqu</i> flavor through microbial inoculation aree discussed, including the advantages, shortcomings, and bottlenecks of microbial inoculation. The findings gained in this study provide valuable information for the efficient production of high-quality <i>Daqu</i> for the brewing of Baijiu.