Insight into microorganisms and flavor substances in traditional Chinese fermented food starter: Daqu

Daqu, a crucial fermentation starter in the production of various Chinese fermented foods, plays a pivotal role in shaping complex enzyme profiles and diverse flavour precursors. This review aims to elucidate the microbial communities within Daqu, focusing on their functionalities in the context of flavour development. We delve into the detection methods of microorganisms and flavour substances in Daqu, employing advanced technologies including high-performance liquid chromatography, gas chromatography, pseudo-targeted metabolomics, and headspace solid-phase microextraction-gas chromatography-mass spectrometry. This review explores high throughput sequencing technologies, including pyrosequencing, clonal library sequencing, metaproteomic, and metagenomics, to gain a comprehensive understanding of the intricate microbial dynamics. Additionally, we discuss the metabolic pathways involved in flavour substance production within Daqu. By synthesizing information on Daqu types, microorganisms present, detection methodologies, and flavour substance metabolic pathways, this review contributes to a deeper comprehension of the intricate processes underpinning the Flavors of Chinese fermented foods.