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Sufu is a traditional umami fermented soybean curd (FSC). We isolated and identified 25 potential umami peptides using ethanol precipitation, dialysis desalination, resin adsorption recovery, nano-HPLC-MS/MS and virtual docking prediction. The results of sensory experiments showed that 23 of the synthetic peptides presented a lower umami threshold than that of MSG (0.50 mg/mL), and 10 peptides had obvious effects of increasing umami and saltiness. Seven peptides were quantified in FSC by UPLC-QQQ-MS, and the content of one novel umami tripeptide ADL (0.51 ± 0.03 mg/mL) was four times its umami threshold (0.125 mg/mL). Taste reconstitution experiments revealed that the umami peptides enhanced the umami and saltiness of the simulated system by 24.53% and 24.00%, respectively. Molecular dynamics proved that hydrogen bonding is the main interaction between peptide and receptors. This study is important for understanding and improving the taste quality of FSC. • The 25 potential taste peptides of sufu were identified by peptidomic. • The content of the novel umami peptide ADL exceeds its threshold by four times in sufu. • Umami peptides were proved to contribute to umami and salty taste of sufu. • Molecular dynamics proved that hydrogen bonding is the main interaction between peptides and receptors T1R1/T1R3. [ABSTRACT FROM AUTHOR]

Non- Saccharomyces yeast (NSY) co-fermentation with Saccharomyces cerevisiae has 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. cerevisiae jiangnan1# in huangjiu brewing. Different fermentation trials were set up and the effects on huangjiu fermentation were also analyzed. Results indicated that simultaneous inoculation could realize the application of NSY, while the appropriate proportion of S. cerevisiae and NSY (1:1 or 1:10) showed differential effects. Finally, three types of NSY strains (Zygosaccharomyces rouxii Non-Sc11, Kloeckera apiculata Non-Sc17, and Candida tropicalis Non-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. cerevisiae jiangnan1# (1:1) resulted in sensory diversity of new huangjiu styles. In addition, the method for evaluation and application of NSY in co-fermentation with S. cerevisiae jiangnan1# in huangjiu brewing had been established for the first time, which could be directly applied in industrial production of huangjiu. [Display omitted] • This is the first report on the use of non- Saccharomyces yeast for huangjiu co-fermentation. • Simultaneous inoculation of non- Saccharomyces yeast and S. cerevisiae is established. • The feasibility of 24 non- Saccharomyces yeast belonging to 13 different genera is evaluated. • Using three non- Saccharomyces yeast results in sensory diversity of new huangjiu styles. • Three strains of non- Saccharomyces yeast with potential industrial application in huangjiu beverage. [ABSTRACT FROM AUTHOR]

Jiuyao as a generally small saccharifying and spontaneously fermenting starter is indispensable for huangjiu brewing. However, jiuyao currently 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 jiuyao by controlling the processing parameters. Saccharomycopsis fibuligera and Rhizopus microsporus were 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 fibuligera CY2111 and Rhizopus microsporus SM4. Meanwhile, the environmental fermentation parameters of jiuyao were optimized to enhance enzyme activities. The glucoamylase and α-amylase activities of fortified jiuyao with 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 jiuyao was used for huangjiu brewing. The flavor profiles determined by gas chromatography–mass spectrometry indicated there was no significant difference in the key aromas between the huangjiu fermented with fortified jiuyao and that of traditional jiuyao. Further, fortified jiuyao produced more pleasant esters in huangjiu such as ethyl isovalerate, isoamyl acetate, and ethyl caprylate. Combined with the sensory evaluation, huangjiu fermented with fortified jiuyao presented stronger fruity aroma. These results demonstrated that careful fermentation settings combined with biofortification technology were feasible to improve jiuyao quality, thus promoting huangjiu flavor. Taken together, it provided scientific guidance to improve traditional handcrafting and scale up the production of jiuyao under controllable fermentation. [Display omitted] • The core saccharifying microbiota of huangjiu jiuyao was revealed. • The fermentation environment of jiuyao was simulated and optimized. • The fortified jiuyao was developed for higher enzyme activities. • The fortified jiuyao could improve the flavor quality of huangjiu. [ABSTRACT FROM AUTHOR]

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 huangjiu quality. 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, Saccharopolyspora and 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 huangjiu at the end of pre-fermentation. Contents of n-hexanol, ethyl isovalerate, ethyl hexanoate and guaiacol in manual huangjiu were significantly higher than those in mechanical one, while the content of 4-vinylguaiacol was lower. [Display omitted] • The microbial community succession of raw wheat qu was identified. • The driving factor was verified by single-factor experiment. • Microbial structure tends to be identical in different part of raw wheat qu. • Driving force of microbiota in raw wheat qu are temperature, water content and oxygen. [ABSTRACT FROM AUTHOR]