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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]

This investigation explores the impact of various fermentation techniques and the inoculation of Bacillus subtilis spores on the physicochemical properties and principal flavor profiles of Huangjiu. Employing sensory analysis, headspace solid-phase microextraction, gas chromatography-tandem mass spectrometry (HS-SPME-GC–MS), and orthogonal partial least squares discriminant analysis (OPLS-DA), we observed that these variables significantly alter the physicochemical attributes of Huangjiu. Our analysis, integrating volatile organic compounds (VOCs) with odor activity values (OAV), revealed that while B. subtilis inoculation modifies the concentrations of key flavor compounds, it does not affect their types. Notably, the inoculation enhances the concentrations of 13 primary flavor compounds, thereby enriching floral and fruity notes while reducing higher alcohol levels. These findings contribute valuable insights into the flavor formation mechanisms of Huangjiu and guide the optimization of fermentation processes. • Bacillus subtilis alters rice wine's physicochemical properties. • Bacillus subtilis mainly affects rice wine's flavor profile. • Bacillus subtilis boosts thirteen key flavor compounds. • Bacillus subtilis enhances floral and fruity flavors. • Bacillus subtilis reduces higher alcohol content. [ABSTRACT FROM AUTHOR]

[Display omitted] • Influence of serving temperature on aroma release and perception of Huangjiu were investigated. • Quantitative description analysis showed 17 attributes significantly influenced by temperature. • Different types and temperatures of Huangjiu were visualized by fingerprint spectral profiles. • Multivariate analysis and aroma adding experiment predicted 22 key odorants in Huangjiu. Serving temperature plays a crucial role in influencing the sensory experience of consumers. In this context, this study investigated the influence of serving temperature on the aroma release and perception of a typical fermented alcoholic beverage named Huangjiu. A quantitative sensory description analysis was conducted, determining serving temperature significantly influenced the 17 sensory attributes in both semi-dry and semi-sweet Huangjiu. The variation in the contents of 41 volatiles in the Huangjiu with temperature was investigated using gas chromatography-ion mobility spectrometry, resulting in volatile content significantly increasing above 30 ℃. The partial least squares discriminant analysis was conducted to predict the variable importance for the projection (VIP) of volatiles, and 22 volatiles (VIP > 1) were screened. These 22 volatiles were confirmed as key odorants influenced by serving temperature though aroma addition experiments. The findings would provide a reference for the effects of serving temperature on the flavor perception of fermented alcoholic beverages. [ABSTRACT FROM AUTHOR]

• Inoculated raw wheat Qu (IRWQ) is a perfect improvement of traditional wheat Qu. • IRWQ maintained the microbial diversity and enhanced hydrolytic enzyme activities. • IRWQ microbiota is firstly disclosed by single molecule real-time DNA sequencing. • The functional microorganisms in IRWQ was firstly analyzied. • Mould, yeast and bacteria contributed different aspects to IRWQ characters. Inoculated raw wheat Qu (IRWQ), which can be produced with high efficiency and low cost while maintaining stable quality, is a new Qu that has been applied to Huangjiu brewing. In this study, single molecule real-time DNA sequencing technology and culture-dependent methods were combined for the first time to study the microbiota and the function of the principle microorganisms in IRWQ. The glucoamylase, amylase and protease contents of IRWQ were 1.17, 1.55 and 2.87-times greater, respectively, than those of traditional wheat Qu. Like traditional wheat Qu, the main volatile flavor compounds in IRWQ were alcohols; however, the esters content was much higher and the acids content was much lower. Single molecule real-time DNA sequencing technology identified 18 fungal species and 59 bacterial species in IRWQ. Then, 30 species were isolated by culture-dependent methods. These species represented about 80% of the total fungal microbiota and 35% of the total bacteria microbiota. Molds were the main contributors of glucoamylase, amylase and protease activities. Aspergillus flavus had the highest glucoamylase and protease activity. Bacillus subtilis and Bacillus amyloliquefaciens also produced high hydrolytic enzyme activities. Saccharomyces cerevisiae produced the largest amounts of aromatics compounds, alcohols, esters and acids. Aldehydes and ketones are mainly produced by molds. [ABSTRACT FROM AUTHOR]

Huangjiu is a popular Chinese traditional alcoholic beverage, while its brewing processes have rarely been explored. We herein report the first gapless, near-finished genome assembly of the industrial strain Aspergillus flavus SU-16 for huangjiu brewing. This work provides insights and supports for the further industrial applications of A. flavus isolates by comprehensively studying of the safety and genomic variations of SU-16. We demonstrated that SU-16 is a non-aflatoxigenic A. flavus at both molecular and metabolic levels. Using of nanopore sequencing technology resulted in a complete genome sequence for all 8 A. flavus chromosomes, as well as the mitochondrion. Genome comparisons of SU-16 with reference strains identified the chromosomal rearrangements, revealed the adaption mechanism of SU-16 to huangjiu ecological niche, and found that SU-16 is a good repository for CAZymes and some bioactive secondary metabolites. The results will help to develop more scientific huangjiu fermentation processes, and explore metabolism pathways of desired or harmful components in huangjiu to improve its quality. • SU-16 was identified as a non-aflatoxigenic A. flavus strain; • Nanopore sequence technology resulted a gapless, near-finished genome assembly of A. flavus SU16; • Metabolic alterations caused by the accumulation of genetic variations are the main driving force for the functional differentiation of A. flavus during domestication; • SU-16 possesses an incomplete aflatoxin biosynthesis gene cluster; • Results provide insights and supports for the further application of SU-16 in the other fields. [ABSTRACT FROM AUTHOR]

[Display omitted] • P. pentosaceus , W. paramesenteroides , R. emersonii, B. spectabilis were dominant in Daqu. • Four Saccharopolyspora species were dominant in wheat Qu. • Flavor metabolic pathways in Qu microbiota were reconstructed. • The dominant microbes in Qu may not be the main functional microbes. Daqu and wheat Qu are saccharification and fermenting agents in Chinese huangjiu and baijiu production. This study aimed to investigate the difference between Daqu and wheat Qu in physicochemical indices, microbial communities, functional genes, and the metabolic network of key microbes responsible for flavor synthesis by whole-metagenome sequencing and metabolite analysis. Herein, physicochemical indices indicated that compared with wheat Qu , Daqu exhibited higher protease and cellulase activity and acidity, and lower glucoamylase and amylase enzyme activity. Metagenomic sequencing reveals that although Daqu and wheat Qu community composition have significant differences at species level, they have similar functional genes. Daqu were enriched in Pediococcus pentosaceus , Weissella paramesenteroides , Rasamsonia emersonii and Byssochlamys spectabilis (22.48% of the total abundance), while wheat Qu harbored greater abundances of Saccharopolyspora (54.78%, Saccharopolyspora rectivirgula , Saccharopolyspora shandongensis , Saccharopolyspora hirsuta , Saccharopolyspora spinose , and Saccharopolyspora erythraea). From a functional perspective, the important functions of Daqu and wheat Qu are both amino acid metabolism and carbohydrate metabolism. Meanwhile, a combined analysis among microbiota, functional genes, and dominant flavors indicated S. shandongensis , S. rectivirgula , and S. spinose might be the main contributor to the synthesis of flavor compounds in wheat Qu , while R. emersonii , W. paramesenteroides , Leuconostoc citreum , Leuconostoc mesenteroides , Weissella cibaria and P. pentosaceus may make the greatest contribution to flavor compounds synthesis in Daqu. This study reveals the microbial and functional dissimilarities of Daqu and wheat Qu , and helps elucidating different metabolic roles of microbes during flavor formation. [ABSTRACT FROM AUTHOR]