Characterisation of physicochemical properties, flavour components and microbial community in Chinese Guojing roasted sesame‐like flavour Daqu. Issue 1 (25th October 2019) - Fan, Guangsen
Abstract: Daqu is a saccharifying and fermentation agent for Baijiu production. It provides ingredients, flavours or flavour precursors, microorganisms and enzymes that influence Baijiu quality and character. Here, a systematic investigation was performed on the physicochemical properties, volatile flavour compounds and microbial community structures of Chinese Guojing roasted sesame‐like flavour Daqu . The results show that the Daqu exhibited high saccharifying ability, but low liquefying and fermenting ability. Analysis by headspace solid‐phase microextraction gas chromatography–mass spectrometry showed that the Daqu and a simulated solid‐state fermentation sample contained 28 and 49 volatile components, including alcohols, esters, aldehydes, benzodiazepines, alkenes and nitrogen containing compounds. The main volatiles were aldehydes, esters and alcohols in Daqu, while the esters, alcohols and phenols were relatively higher in the solid‐state fermentation sample. With the microbial flora, Bacillus, Actinobacteria _norank, Thermoactinomyces, Enterobacteriaceae _norank, Enterobacter, Actinopolyspora, Kroppenstedtia, Pseudomonas and Sphingobium were the main prokaryotic microorganisms. The dominant fungi were Thermomucor, Trichocomaceae _Incertae Sedis, Absidia, Eurotiomycetes _Incertae Sedis, Mucorales _Incertae Sedis and Eurotiales _Incertae Sedis. By systematically characterising the physicochemical properties, flavour compounds and microorganisms in Daqu, this study increases the understanding of Daqu and provides information for improvements in Baijiu production and quality. © 2019 The Institute of Brewing & Distilling