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Non-Saccharomycesyeast (NSY) co-fermentation with Saccharomyces cerevisiaehas been widely used to produce high-quality fermented alcoholic beverages. In this study, we evaluated the feasibility of 24 NSY strains belonging to 13 different genera co-fermentation with S. cerevisiaejiangnan1# in huangjiubrewing. Different fermentation trials were set up and the effects on huangjiufermentation were also analyzed. Results indicated that simultaneous inoculation could realize the application of NSY, while the appropriate proportion of S. cerevisiaeand NSY (1:1 or 1:10) showed differential effects. Finally, three types of NSY strains (Zygosaccharomyces rouxiiNon-Sc11, Kloeckera apiculataNon-Sc17, and Candida tropicalisNon-Sc21) with high ethanol content (>16% vol), moderate concentration of higher alcohols (<400 mg/L, 14% vol), higher production of esters (P < 0.05), and lower organic acid (P < 0.05) were obtained ultimately. The sensory evaluation demonstrated that using no less than one kind of the three NSY strains in simultaneous fermentation with S. cerevisiaejiangnan1# (1:1) resulted in sensory diversity of new huangjiustyles. In addition, the method for evaluation and application of NSY in co-fermentation with S. cerevisiaejiangnan1# in huangjiubrewing had been established for the first time, which could be directly applied in industrial production of huangjiu.

Jiuyaoas a generally small saccharifying and spontaneously fermenting starter is indispensable for huangjiubrewing. However, jiuyaocurrently in use is facing a major challenge of standardized manufacturing because of its open operating environment and rather primitive operations. This study provided a stead manufacturing procedure for jiuyaoby controlling the processing parameters. Saccharomycopsis fibuligeraand Rhizopus microsporuswere revealed as the core functional species related to starch-degrading enzyme activities with single-molecule real-time (SMRT) sequencing. Two strains with high starch-degrading abilities were successfully isolated and identified as Saccharomycopsis fibuligeraCY2111 and Rhizopus microsporusSM4. Meanwhile, the environmental fermentation parameters of jiuyaowere optimized to enhance enzyme activities. The glucoamylase and α-amylase activities of fortified jiuyaowith strain CY2111 and SM4 were 3.07 and 3.15 times that of traditional jiuyao, respectively. Moreover, the alcohol content increased by approximately 7.5% when fortified jiuyaowas used for huangjiubrewing. The flavor profiles determined by gas chromatography–mass spectrometry indicated there was no significant difference in the key aromas between the huangjiufermented with fortified jiuyaoand that of traditional jiuyao. Further, fortified jiuyaoproduced more pleasant esters in huangjiusuch as ethyl isovalerate, isoamyl acetate, and ethyl caprylate. Combined with the sensory evaluation, huangjiufermented with fortified jiuyaopresented stronger fruity aroma. These results demonstrated that careful fermentation settings combined with biofortification technology were feasible to improve jiuyaoquality, thus promoting huangjiuflavor. Taken together, it provided scientific guidance to improve traditional handcrafting and scale up the production of jiuyaounder controllable fermentation.

As the core raw material of huangjiu(Chinese rice wine) production and brewing, changes of physichemical factors during the fermentation process significantly affect the succession of the microbial community of raw wheat qu(RWQ), also playing important role in huangjiuquality. In this report we analyzed the community structure and driving force RWQ microorganisms with different processes (manual qu, MAQ; mechanical qu, MEQ), and evaluating the flavor of huangjiu. The production procedure was divided into three stages. Dominant microorganisms were Aspergillus, Alternaria, Epicoccus, Bacillus, Pantoea, Saccharopolysporaand Staphylococcus. In early stage, microbial community of MAQ was significantly correlated with temperature and water content, oxygen in middle stage, while no significant driving force in the last stage. Water content and oxygen affected MEQ community significantly in early stage, while in the final stage, fungal community was affected by both temperature and water content, and bacterial community was significantly correlated with oxygen. Glucoamylase activity reached its maximum at 50 °C, while the α-amylase activity decreased with the rise of temperature. The highest amylase activity was obtained with 19% initial water addition. Amylase activity showed positive correlation with the thickness of RWQ. The total amount of organic acids was higher in mechanical huangjiuat the end of pre-fermentation. Contents of n-hexanol, ethyl isovalerate, ethyl hexanoate and guaiacol in manual huangjiuwere significantly higher than those in mechanical one, while the content of 4-vinylguaiacol was lower.