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Objective: To investigate the protective effects of mannan oligosaccharide (MOS) and partially hydrolyzed guar gum (PHGG) on liver injury induced by long-term alcohol intake in mice. Methods: Mice were randomly divided into control (Ctrl), model (EtOH), positive control (PC, silymarin at 86 mg/(kg·d)), MOS intervention (2 000 mg/(kg·d)) and PHGG intervention (2 000 mg/(kg·d)) groups. A Lieber-DeCarli model of chronic alcoholic liver injury (ALD) was established in this study. After five weeks of feeding, the levels of liver function, oxidative stress and inflammatory factors were measured. Hematoxylin-eosin (HE) staining and oil red O (ORO) staining were used to observe hepatic histopathological alterations. The mRNA and protein expression levels of ileal tight junction proteins (zonula occludens-1 and occludin) were detected by real-time fluorescence quantitative polymerase chain reaction (qPCR) and immunofluorescence staining, respectively. The hepatic lipopolysaccharide (LPS) level was quantitatively determined by enzyme-linked immunosorbent assay (ELISA). Besides, the contents of acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid and caproic acid in fecal samples were quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS). Results: Supplementation of MOS and PHGG could significantly attenuate hepatic steatosis, lipid accumulation, oxidative stress and inflammation induced by long-term ethanol exposure. Additionally, compared with the EtOH group, MOS and PHGG intake markedly improved liver function and intestinal barrier function, inhibited intestinal LPS leakage, and increased intestinal short-chain fatty acids (SCFAs) levels. Conclusion: Guar gum-derived MOS and PHGG could effectively alleviate chronic ALD in mice by enhancing intestinal integrity and regulating intestinal SCFA levels.

Summary: The wheat Qu and Lin‐fan yeast starter are two vital components of Huangjiu brewing, the microbiome composition of which can have a major impact on the end product's quality. This investigation aimed to investigate and compare the fungal diversity of eight starters, including four wheat Qus and four Lin‐fan yeast starters collected from different manufacturers of Shaoxing Huangjiu using high‐throughput sequencing (HTS) technology. Significant variation was observed in the fungal community composition among different starter samples. Fusarium, Epicoccum, Aspergillus and Alternaria were the most predominant fungal genera in wheat Qus. In contrast, Lin‐fan yeast starters possessed relatively simple fungal communities and were predominated by Saccharomyces and Saccharomycopsis. LEfSe analysis showed that nine genus‐level fungal taxa could be retrieved to differentiate the two starter types. Furthermore, the complicated association among the dominant fungi in traditional starters was revealed by utilising Spearman's correlation‐based network analysis. A total of 42 positive and 28 negative correlations were identified respectively. Ultimately, this investigation described the fungal communities in wheat Qus and Lin‐fan yeast starters and will aid in screening fermentation strains, which can remarkably enhance the quality of Shaoxing Huangjiu. [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]

Aromatic alcohols (including β-phenylethanol, tyrosol and tryptophol) could contribute positively to the aroma flavor of huangjiu at an appropriate amount. In this study, it was found that the aromatic alcohols in huangjiu were predominantly synthesized by Saccharomyces cerevisiae HJ01. The Ehrlich pathway and shikimate pathway, including 31 genes, are responsible for aromatic alcohol biosynthesis in S. cerevisiae. During the first 120 h of huangjiu fermentation, the genes GAP1 HJ01 (permease), BAT2 HJ01 (transaminase), PDC1 HJ01 and PDC5 HJ01 (pyruvate decarboxylase), and ADH1 HJ01 (alcohol dehydrogenase) formed integrated Ehrlich pathway are responsible for aromatic alcohol biosynthesis. In S. cerevisiae HJ01, the mutations in the promoter region of genes GAP1 HJ01, BAT2 HJ01, PDC1 HJ01, and PDC5 HJ01 involved in the Ehrlich pathway increased the promoter strength and transcriptional levels of related genes. The addition of 20 U/g acid protease could substantially increase the expression levels of genes involved in the Ehrlich pathway, and therefore there were 34.7% increasing for the concentration of total aromatic alcohols. • Aromatic alcohols in huangjiu are synthesized by Saccharomyces cerevisiae. • Aromatic alcohols in huangjiu are mainly synthesized through the Ehrlich pathway. • Key genes and promoter mutations in Ehrlich pathway were identified. • Acid protease enhanced expression level of key genes. [ABSTRACT FROM AUTHOR]

2-Phenylethanol, an aromatic compound often found in fermented foods, is among the most abundant aromatic compounds in huangjiu (Chinese rice wine). The 2-phenylethanol found in huangjiu is produced by Saccharomyces cerevisiae HJ01, which produces much more 2-phenylethanol than the type strain, S. cerevisiae W303. Feedback regulation of 2-phenylethanol biosynthesis in S. cerevisiae has been carefully studied, except for the behavior of prephenate dehydratase (PDT; EC 4.2.1.51). Mutation (I161K, L239P and Q250H) in PDT were found in S. cerevisiae HJ01, and a structure-based analysis suggested the presence of conserved l -Phe binding sites. The purified PDT from S. cerevisiae strains HJ01 and W303 were found to be inhibited by l -Phe. The specific activity of the PDTHJ01 was 1.27-fold greater than that of the PDTW303. It also showed greater substrate affinity (K m , 11.1–15.9 mM), catalytic efficiency (kcat / Km , 58.9 to 51.7 L/(mmol•s)), and thermal stability, but was less susceptible to feedback inhibition (K i , 3.97 to 3.35 mM). Thus, mutations in the PDT from S. cerevisiae HJ01 contribute to the higher 2-phenylethanol concentration found in huangjiu. • Prephenate dehydratase (PDT) in S. cerevisiae was feedback inhibited by l -Phe. • PDT in S. cerevisiae HJ01 showed greater substrate affinity, catalytic efficiency. • Mutation of I161K, L239P and Q250H resulted less sensitive inhibition of l -Phe. [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]

Background: To improve the quality of red starter wine, this study explored the effects of baking red kojic rice at varying temperatures on the physicochemical characteristics of red starter wine. Baking was predicated on understanding crucial enzyme activities and starch granule structure of red kojic rice at 75, 95, and 105 °C, leading to the production of three red starter wine variants (BHQW1, BHQW2, and BHQW3)., Results: The results revealed an increased alcohol (increase 0.50%), total sugar (increase 0.14 g L -1 ), and total acid (increase 0.54 g L -1 ) content in red starter wine fermented using baked red kojic rice compared with the control group (wine fermented with unbaked rice, HQW). Furthermore, both the 105 °C baked red kojic rice and its resulting BHQW3 demonstrated significantly higher red color values than HQW (increase 2.03 U g -1 and 0.15 U mL -1 respectively). The highest lovastatin content was presented in red kojic rice baked at 105 °C and its corresponding fermented wine (1420.63 ± 507.9 μg g -1 and 3368.87 ± 228.16 μg L -1 respectively). Additionally, BHQW groups displayed higher total flavonoids and phenols content than HQW. Regarding antioxidant capacity, all BHQW groups showed stronger overall antioxidant capacity than HQW. The determination of volatile components revealed the highest content of volatile compounds in BHQW2 (2621.19 ± 548.24 μg L -1 ) and significantly higher volatile esters in BHQW1 (254.46 ± 16.63 μg L -1 ). Moreover, 16 volatile compounds were identified only in BHQW groups, including isoamyl caprylate, 2-ethylhexyl alcohol, and benzaldehyde., Conclusion: Our findings suggested that the baking technique of red kojic rice could enhance the quality of red starter wine through enhancing antioxidant properties, increasing functional components, and enriching volatile flavor compounds, thus providing a foundation for new techniques in red starter wine production. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)