Sequencing-based screening of functional microorganism to decrease the formation of biogenic amines in Chinese rice wine

Grafting of syringic acid onto fucoidan: Enhanced functional properties and therapeutic potential in histamine-induced liver injury

This study explores the grafting of syringic acid onto fucoidan and assesses the resultant graft's (FS) enhanced functional properties and therapeutic potential in a histamine-induced liver injury model. Utilizing a redox system of ascorbic acid and hydrogen peroxide, the grafting process achieved a grafting rate of 290.45 mg CAE/g, confirmed through UV-Vis spectroscopy, FT-IR spectroscopy, scanning electron microscopy, and thermogravimetric analysis. In vivo investigations using histamine-sensitive mice demonstrated that FS significantly mitigated histamine-induced damage, evidenced by improvements in body weight, organ index, and colon length. FS exhibited superior efficacy in restoring liver function indices (ALT, AST, ALP, GGT), enhancing antioxidant defenses (GSH, SOD), and reducing oxidative stress markers (MDA). Anti-inflammatory effects included reduced levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and modulation of apoptosis-related proteins (BCl2, BAX). Additionally, FS upregulated key antioxidant genes in the Nrf2/KEAP1 pathway and downregulated inflammatory genes in the NF-κB pathway. Restoration of colonic tight junction proteins (ZO-1, Occludin, Claudin-1) and normalization of gut microbiota composition further underscored the therapeutic potential of FS. The study highlights the significant enhancement in functional properties of fucoidan through SA grafting, presenting FS as a promising candidate for developing functional foods and nutraceuticals aimed at preventing and mitigating liver damage and related disorders.

Biogenic amines degradation ability of Saccharomyces cerevisiae I45 and Pichia sp. NW5 & LB60 and their application in beer fermentation

Biogenic amines (BAs) are abundant in craft beer and pose toxicological risks to consumers. Certain microbes have shown potential for degrading BAs. This study, for the first time, used beer as a fermentation system to screen three yeast strains: Saccharomyces cerevisiae I45, Pichia kluyveri NW5, and Pichia terricola LB60, which effectively reduced BA levels in stout beer. The degradation rates for tryptamine by S. cerevisiae I45, tyramine by P. kluyveri NW5, and putrescine by P. terricola LB60 were 55.76 %, 41.75 %, and 36.53 %, respectively. After mixed fermentation, the total BAs degradation rate in the stout beer was 48.81 %, and the highest degradation rates of the representative bioamines tryptamine and putrescine were 40.52 % and 50.96 %, respectively. Additionally, glycerol yield and ester content were significantly increased, without negatively impacting the beer's volatile aroma components, while enhancing characteristic aromas like rose and tropical fruit. These findings provide a theoretical basis and technical guidance for improving the safety and sensory quality of craft beer.

Exploring microbial dynamics and metabolic pathways shaping flavor profiles in Huangjiu through metagenomic analysis

In the production of Huangjiu (Chinese rice wine), fermentation microbiota plays a crucial role in flavor formation. This study investigates the microbial dynamics and metabolic pathways that shape the flavor profiles of Huangjiu using different starters. Sensory evaluation and metabolite analysis of six starters revealed significant differences in ester, fruity, and sweet aromas. Saccharomyces, Aspergillus, and Rhizopus were identified as the dominant genera significantly impacting fermentation. Metagenomic species and functional gene annotations of Huangjiu starters elucidated the metabolic pathways for key flavor compounds synthesis pathways. Enzyme genes involved in these pathways were classified and annotated to microbial genera using the NR database, identifying 231 classes of relevant catalytic enzymes and 154 microbial genera. A metabolic relationship between flavor compound formation and different microbial genera was established using catalytic enzymes as a bridge. This study highlights the impact of starter composition on the final product and provides new insights for optimizing starters to enhance Huangjiu flavor quality.

Correlation between the bacterial community succession and purine compound changes during Huangjiu fermentation

Purine is mainly culprit of hyperuricemia (HUA) and gout, which is widely present in Huangjiu in the form of free bases. Bacterial succession plays an important role in quality control in Huangjiu. The correlation between the purine compound content and the bacterial communities during the fermentation process has not yet been evaluated. In this study, high-throughput sequencing (HTS) technology was used to monitor the bacterial community composition of Huangjiu at different fermentation stages. The correlation between the bacterial community and the contents of physicochemical properties and purine compounds were evaluated using the Spearman analysis method. The key enzymes of purine metabolism pathway in the microbial community were analyzed by bioinformatics using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). The results showed that the purine content in Huangjiu increased gradually in 0∼9d of fermentation (21.05-65.71 mg/L), and stabilized gradually in 12∼18d (65.63-69.55 mg/L), while the abundance of lactic acid bacteria (LAB) of bacterial microbial flora were increased (0∼9d) and then stabilized (12∼18d). Moreover, Lactobacillus acetotolerans and Lactobacillus helveticus were highly correlated positively with purine contents, while Limosilactobacillus fermentum and Lactiplantibacillus plantarum were correlated negatively. In addition, the dominant strains of bacteria were involved in the metabolism of purine, and the key enzymes for purine compound synthesis were more abundant than that for purine degradation. This study is helpful to scientifically understand the formation mechanism of purines, providing a basis for screening functional strains of purine degrading to accurately regulate purine level in Huangjiu.

Therapeutic Potential of Fucoidan in Alleviating Histamine-Induced Liver Injury: Insights from Mice Studies

Histamine, a bioactive component in certain foods such as Huangjiu has been associated with liver injury and disrupted intestinal balance. This study explored the potential therapeutic effects of fucoidan (FCD) in mitigating histamine-induced imbalances in mice. We found that FCD mitigated liver injury, reducing transaminases, oxidative stress, and inflammation. Histological improvements included decreased cell infiltration and necrosis. FCD restored tight junction proteins and suppressed inflammation-related genes. Western blot analysis revealed FCD's impact on TGF-β1, p-AKT, AKT, CYP2E1, Grp78, NLRP3, Cas-1, and GSDMD. Gut LPS levels decreased with FCD. Gut microbiota analysis showed FCD's modulation effect, reducing Firmicutes and increasing Bacteroides. FCD demonstrates potential in alleviating histamine-induced liver injury, regulating inflammation, and influencing gut microbiota. Further research exploring higher dosages and additional parameters is warranted.

Application of Strain Selection Technology in Alcoholic Beverages: A Review

The diversity of alcohol beverage microorganisms is of great significance for improving the brewing process and the quality of alcohol beverage products. During the process of making alcoholic beverages, a group of microorganisms, represented by yeast and lactic acid bacteria, conducts fermentation. These microorganisms have complex synergistic or competitive relationships, and the participation of different microorganisms has a major impact on the fermentation process and the flavor and aroma of the product. Strain selection is one of the key steps. Utilizing scientific breeding technology, the relationship between strains can be managed, the composition of the alcoholic beverage microbial community can be improved, and the quality and flavor of the alcoholic beverage products can be increased. Currently, research on the microbial diversity of alcohol beverages has received extensive attention. However, the selection technology for dominant bacteria in alcohol beverages has not yet been systematically summarized. To breed better-quality alcohol beverage strains and improve the quality and characteristics of wine, this paper introduces the microbial diversity characteristics of the world's three major brewing alcohols: beer, wine, and yellow wine, as well as the breeding technologies of related strains. The application of culture selection technology in the study of microbial diversity of brewed wine was reviewed and analyzed. The strain selection technology and alcohol beverage process should be combined to explore the potential application of a diverse array of alcohol beverage strains, thereby boosting the quality and flavor of the alcohol beverage and driving the sustainable development of the alcoholic beverage industry.

Fermentation properties and functional stability of dough starter Jiaozi and Laomian after frozen storage

Purpose

This study aims to investigate the effects of frozen storage on the stability of traditional dough starters in China.

Methods

The microbial community structure and abundance of related metabolic genes in different fermented sourdough prepared by Jiaozi (JZ) and Laomian (LM) starters before and after frozen storage at -20°C for half a year were analyzed using the shotgun metagenomic sequencing method, and differences in characteristics of texture in steamed bread were also compared by formal methods.

Results

The fermentation ability (FA) and metabolic activities of yeast in the JZH sourdough (started by JZ which was stored at -20°C for half a year) were better than those of LMH sourdough (started by LM which was stored at -20°C for half a year). The dominant genera of Acetobacter were found to be increased in the JZH0 sourdough (started by JZH and fermented for 0 h) and those of Lactobacillus were found to be decreased. Lactobacillus (98.72%), Pediococcus (0.37%), Saccharomyces (0.27%), and Acetobacter (0.01%), were dominant in sourdough LMH0 (started by LMH and fermented for 0 h). The abundances of "oxidative phosphorylation-related enzymes" and the "biosynthesis of glutamate"-related enzymes and genes related to "biosynthesis of glutamate" and "unsaturated fatty acid" were higher in JZH0 than in the JZ0 sourdough (started by JZ without being frozen and fermented for 0 h). The good FA of yeast, the acid production capacity of bacteria in the sourdough, and the quality of the JZH steamed bread (made by the JZH starter) indicated the better freezing tolerance of the microorganisms in JZ than in LM.

Conclusion

The conclusion of this study suggests the better application potential of the JZ as the fermentation starter in actual production.

Screening and evaluating microorganisms with broad-spectrum biogenic amine-degrading ability from naturally fermented dry sausage collected from Northeast China

This study aimed to screen autochthonous strains with broad-spectrum biogenic amine (BA) degradation ability from traditional dry sausages and to evaluate their BA-degrading ability in dry sausages. A total of 120 strains were isolated from dry sausages collected from various regions in Northeast China, and 35 of 120 isolates were identified as non-BA producing strains by the in vitro agar method. The random amplified polymorphic DNA polymerase chain reaction technique genotyped these 35 isolates into 18 biotypes. Moreover, high performance liquid chromatography (HPLC) quantification showed that six strains (Latilactobacillus sakei MDJ6; Lactiplantibacillus plantarum SH7; Weissella hellenica DQ9; Staphylococcus saprophyticus JX18 and SYS8; and Macrococcus caseolyticus SYS11) of the 18 biotypes exhibited broad-spectrum BA-degrading ability, all of which had various levels of amine oxidase activity with monoamine oxidase and diamine oxidase activities ranged of 6.60-619.04 and 26.32-352.81 U/mg protein, respectively. These six strains were subsequently inoculated into dry sausages and the results showed that they exhibited varying degrees of BA-degrading ability, of which strain Lat. sakei MDJ6 allowed to have less BA production on dry sausage with a final concentration of 61.33 mg/kg.

In-situ substitution and community dynamics modeling for enhanced safety in Chinese rice wine brewing

This research paper focuses on the application of the "Design-Build-Test-Learn" framework to design and evaluate a synthetic microbial community aimed at studying the impact of Lactic Acid Bacteria (LAB) interactions and fitness on the formation of biogenic amines (BAs) in Chinese rice wine (CRW). The study reveals a close correlation between the assembly model of LAB and the accumulation of BAs in CRW, and multiple interactions were observed between amine-producing and non-amine-producing LAB, including commensalism, amensalism, and competition. The commensalism among amine-producing LAB was found to promote BAs accumulation through metabolic cross-feeding of amino acids. Moreover, the higher-order interaction community was designed to regulate the BAs formation effectively. For instance, the interference of Lactiplantibacillus plantarum (ACBC271) resulted in the elimination of amine-producing LAB viability, resulting in a 22% decrease (not exceeding 43.54 mg/L) in the total amount of BAs. Simulation of community dynamics models further suggests that LAB with quantitative social interactions can effectively control LAB accumulation in CRW by forecasting fluctuation in BAs generation through fitness competition and metabolic interference. Overall, this study provides valuable insights into the complex interaction networks within microbial communities in traditional fermentation ecosystems. It also proposes a novel approach for quality control of nitrogen food safety factors in fermented foods.

Insights into microbial communities and metabolic profiles in the traditional production of the two representative Hongqu rice wines fermented with Gutian Qu and Wuyi Qu based on single-molecule real-time sequencing

Hongqu rice wine, a famous traditional fermented alcoholic beverage, is brewed with traditional Hongqu (mainly including Gutian Qu and Wuyi Qu). This study aimed to compare the microbial communities and metabolic profiles in the traditional brewing of Hongqu rice wines fermented with Gutian Qu and Wuyi Qu. Compared with Hongqu rice wine fermented with Wuyi Qu (WY), Hongqu rice wine fermented with Gutian Qu (GT) exhibited higher levels of biogenic amines. The composition of volatile flavor components of Hongqu rice wine brewed by different fermentation starters (Gutian Qu and Wuyi Qu) was obviously different. Among them, ethyl acetate, isobutanol, 3-methylbutan-1-ol, ethyl decanoate, ethyl palmitate, ethyl oleate, nonanoic acid, 4-ethylguaiacol, 5-pentyldihydro-2(3H)-furanone, ethyl acetate, n-decanoic acid etc. were identified as the characteristic aroma-active compounds between GT and WY. Microbiome analysis based on high-throughput sequencing of full-length 16S rDNA/ITS-5.8S rDNA amplicons revealed that Lactococcus, Leuconostoc, Pseudomonas, Serratia, Enterobacter, Weissella, Saccharomyces, Monascus and Candida were the predominant microbial genera during the traditional production of GT, while Lactococcus, Lactobacillus, Leuconostoc, Enterobacter, Kozakia, Weissella, Klebsiella, Cronobacter, Saccharomyces, Millerozyma, Monascus, Talaromyces and Meyerozyma were the predominant microbial genera in the traditional fermentation of WY. Correlation analysis revealed that Lactobacillus showed significant positive correlations with most of the characteristic volatile flavor components and biogenic amines. Furthermore, bioinformatical analysis based on PICRUSt revealed that microbial enzymes related to biogenic amines synthesis were more abundant in GT than those in WY, and the enzymes responsible for the degradation of biogenic amines were less abundant in GT than those in WY. Collectively, this study provides important scientific data for enhancing the flavor quality of Hongqu rice wine, and lays a solid foundation for the healthy and sustainable development of Hongqu rice wine industry.

Mitigation of microbial nitrogen-derived metabolic hazards as a driver for safer alcoholic beverage choices: An evidence-based review and future perspectives

Alcoholic beverages have been enjoyed worldwide as hedonistic commodities for thousands of years. The unique quality and flavor are attributed to the rich microbiota and nutritional materials involved in fermentation. However, the metabolism of these microbiota can also introduce toxic compounds into foods. Nitrogen-derived metabolic hazards (NMH) are toxic metabolic hazards produced by microorganisms metabolizing nitrogen sources that can contaminate alcoholic beverages during fermentation and processing. NMH contamination poses a risk to dietary safety and human health without effective preventive strategies. Existing literature has primarily focused on investigating the causes of NMH formation, detection methods, and abatement techniques for NMH in fermentation end-products. Devising effective process regulation strategies represents a major challenge for the alcoholic beverage industry considering our current lack of understanding regarding the processes whereby NMH are generated, real-time and online detection, and the high degradation rate after NMH formation. This review summarizes the types and mechanisms of nitrogenous hazard contamination, the potential risk points, and the analytical techniques to detect NMH contamination. We discussed the changing patterns of NMH contamination and effective strategies to prevent contamination at different stages in the production of alcoholic beverages. Moreover, we also discussed the advanced technologies and methods to control NMH contamination in alcoholic beverages based on intelligent monitoring, synthetic ecology, and computational assistance. Overall, this review highlights the risks of NMH contamination during alcoholic beverage production and proposes promising strategies that could be adopted to eliminate the risk of NMH contamination.

Integrated meta-omics approaches reveal Saccharopolyspora as the core functional genus in huangjiu fermentations

Identification of the core functional microorganisms in food fermentations is necessary to understand the ecological and functional processes for making those foods. Wheat qu, which provides liquefaction and saccharifying power, and affects the flavor quality, is a key ingredient in ancient alcoholic huangjiu fermentation, while core microbiota of them still remains indistinct. In this study, metagenomics, metabolomics, microbial isolation and co-fermentation were used to investigate huangjiu. Although Aspergillus is usually regarded as core microorganism in wheat qu to initiate huangjiu fermentations, our metagenomic analysis showed that bacteria Saccharopolyspora are predominant in wheat qu and responsible for breakdown of starch and cellulose. Metabolic network and correlation analysis showed that Saccharopolyspora rectivirgula, Saccharopolyspora erythraea, and Saccharopolyspora hirsuta made the greatest contributions to huangjiu's metabolites, consisting of alcohols (phenylethanol, isoamylol and isobutanol), esters, amino acids (Pro, Arg, Glu and Ala) and organic acids (lactate, tartrate, acetate and citrate). S. hirsuta J2 isolated from wheat qu had the highest amylase, glucoamylase and protease activities. Co-fermentations of S. hirsuta J2 with S. cerevisiae HJ resulted in a higher fermentation rate and alcohol content, and huangjiu flavors were more similar to that of traditional huangjiu compared to co-fermentations of Aspergillus or Lactiplantibacillus with S. cerevisiae HJ. Genome of S. hirsuta J2 contained genes encoding biogenic amine degradation enzymes. By S. hirsuta J2 inoculation, biogenic amine content was reduced by 45%, 43% and 62% in huangjiu, sausage and soy sauce, respectively. These findings show the utility of Saccharopolyspora as a key functional organism in fermented food products.

Metagenomic Insights into the Regulatory Effects of Microbial Community on the Formation of Biogenic Amines and Volatile Flavor Components during the Brewing of Hongqu Rice Wine

As one of the typical representatives of Chinese rice wine (Huangjiu), Hongqu rice wine is produced with glutinous rice as the main raw material and Hongqu as the fermentation starter. The complex microbial flora in the brewing process may have a great influence on the formation of the flavor quality and drinking safety of Hongqu rice wine. Previous studies have shown that high biogenic amine (BA) content in rice wine has potential physiological toxicity and has become a bottleneck problem restricting the development of the rice wine industry. This study aimed to evaluate the regulatory effects of the microbial community on the formation of BAs and volatile flavor components during the brewing of Hongqu rice wine. The results demonstrated that histamine, putrescine, cadaverine, tyramine, tryptamine, spermine, and spermidine were the main BAs in Hongqu rice wine. The contents of putrescine, cadaverine, histamine, tyramine, and spermidine in Hongqu rice wine of HBAs (with higher BAs content) were significantly higher than those in LBAs (with lower BAs content). GC-MS testing results showed that there were significant differences in the composition of volatile organic compounds (VOCs) between HBAs and LBAs. Among them, VOCs such as 2-methoxy-4-vinylphenol, ethyl caprate, phenethyl acetate, ethyl lactate, ethyl myristate, ethyl palmitate, ethyl n-octadecanoate, ethyl oleate, and ethyl linoleate were identified as the characteristic volatile components with significant differences between HBAs and LBAs. Microbiome analysis based on metagenomic sequencing revealed that unclassified_g_Pantoea, Klebsiella pneumoniae, Panobacter disperse, unclassified_f_Enterobacteriaceae, Leuconostoc mesenteroides, and Saccharomyces cerevisiae were the dominant microbial species in the HBA brewing process, while Weissella confuse, Pediococcus acidilactici, Saccharomyces cerevisiae, and Aspergillus niger were the dominant microbial species in the LBA brewing process. Furthermore, correlation heatmap analysis demonstrated that BAs were positively related to Lactobacillus curvatus, Lactococcus lactis, and Leuconostoc mesenteroides. Bioinformatical analysis based on the KEGG database revealed that the microbial genes encoding enzymes involved in BAs' synthesis were more abundant in HBAs, and the abundances of microbial genes encoding enzymes related to BAs' degradation and the metabolism of characteristic volatile components were higher in LBAs. Overall, this work provides important scientific data for enhancing the flavor quality of Hongqu rice wine and lays a solid foundation for the healthy development of the Hongqu rice wine industry.

Developing an innovative raw wheat Qu inoculated with Saccharopolyspora and its application in Huangjiu

BACKGROUND

Mechanized Huangjiu is a stable product, is not subject to seasonal production restrictions, and markedly reduces labor intensity compared to traditional manual Huangjiu. However, the bitterness of mechanized Huangjiu impedes its further development.

RESULTS

Based on process optimization, when the fermentation temperature was 45 °C and the fermentation time was 122 h, the inoculation amount of Saccharopolyspora was 5%, the amount of added water was 26%, and the glucoamylase and amylase activities of wheat Qu increased by 27% and 40% respectively, compared with those before optimization. Huangjiu fermented by raw wheat Qu inoculated with Saccharopolyspora rosea F2014 showed a significant (P < 0.05) decrease in bitter amino acid content (1.24 vs. 2.86 g L^-1 , a decrease of 56%), which attenuated its bitterness.

CONCLUSION

An innovative fermentation process of inoculating Saccharopolyspora into raw wheat Qu was developed for the first time. Such a process could be used to control bitterness based on raw wheat Qu inoculated with Saccharopolyspora rosea F2014, instead of traditional wheat Qu in Huangjiu fermentation. © 2022 Society of Chemical Industry.

Effects of the microbial community on the formation of volatile compounds and biogenic amines during the traditional brewing of Hongqu rice wine

As a typical representative of Chinese rice wine (Huangjiu), Hongqu rice wine is famous for its red color, mellow taste and strong fragrance. However, due to the open brewing environment and traditional fermentation technology, there are some safety risks in traditional brewed Hongqu rice wine, such as a certain amount of biogenic amines. In this study, the dynamic changes and the differences of microbial communities and volatile flavor components between two types of Hongqu rice wine with high and low biogenic amine contents (LBAW and HBAW) during the traditional brewing were systematically investigated. The results showed that the total biogenic amine contents in LBAW and HBAW were 20.91 and 69.06 mg/L, respectively. The contents of putrescine, cadaverine, spermine and spermidine in HBAW were significantly higher than those in LBAW, and it was noteworthy that spermine content in HBAW was 17.62 mg/L, which was not detected in LBAW. In addition, the volatile flavor characteristics of the two kinds of Hongqu rice wine were obviously different. The contents of acetophenone, n-butyl butanoate and benzothiazole were obviously higher in HBAW, while the contents of isoamyl acetate, ethyl lactate, ethyl caprate and phenylethyl alcohol were significantly higher in LBAW. High-throughput sequencing of 16S/ITS amplicon revealed that Weissella, Kosakonia, Pantoea, Monascus, Saccharomyces and Millerozyma were the predominant microbial genera during the traditional brewing of HBAW, while Weissella, Kosakonia, Monascus, Saccharomyces and Issatchenkia were the predominant microbial genera during the traditional brewing of LBAW. Correlation analysis revealed that biogenic amines were significantly negatively correlated with unclassified_o_Saccharomycetales, Cyberlindnera, Zygoascus, Aspergillus and Acinetobacter, but positively correlated with Lactobacillus, Pediococcus, Millerozyma and Apiotrichum. In addition, we also found that Lactobacillus, Pediococcus and Saccharomyces were significantly positively correlated with most of the volatile flavor components, while Candida, Trichosporon and Monascus were significantly negatively correlated with most of the volatile flavor components. In addition, bioinformatical analysis based on PICRUSt demonstrated that the key enzymes for biogenic amine biosynthesis were more abundant in the microbial community of HBAW than LBAW. These findings demonstrate that the formations of volatile flavor and biogenic amines in Hongqu rice wine are influenced by microbial community during the fermentation. This work facilitates scientific understanding of the formation mechanism of biogenic amines, and may be useful to develop effective strategies to improve the quality of Hongqu rice wine.

Histamine Causes Pyroptosis of Liver by Regulating Gut-Liver Axis in Mice

Huangjiu usually caused rapid-drunkenness and components such as β-benzyl ethanol (β-be), isopentanol (Iso), histamine (His), and phenethylamine (PEA) have been reported linked with intoxication. However, the destructive effect of these components on gut microbiota and liver is unclear. In this study, we found oral treatment of these components, especially His, stimulated the level of oxidative stress and inflammatory cytokines in liver and serum of mice. The gut microbiota community was changed and the level of lipopolysaccharide (LPS) increased significantly. Additionally, cellular pyroptosis pathway has been assessed and correlation analysis revealed a possible relationship between gut microbiota and liver pyroptosis. We speculated oral His treatment caused the reprogramming of gut microbiota metabolism, and increased LPS modulated the gut-liver interaction, resulting in liver pyroptosis, which might cause health risks. This study provided a theoretical basis for the effect of Huangjiu, facilitating the development of therapeutic and preventive strategies for related inflammatory disorders.

Interaction between bacterial diversity and biogenic amines production in a salted mackerel stored at soft frozen (-7℃-0℃) storage

The bacterial diversity of salted mackerel "one-night courtyard" at soft frozen area (-7℃-0℃) storage was studied. The fish samples at 0, 14, 21, 28, and 35 days were analysis for bacterial structure using high-throughput sequencing technologies (HTS) and biogenic amines using high-performance liquid chromatography (HPLC). The analysis results of HTS showed that the dominant bacteria species was varied gradually following with storage time. On the 0th, 21st, and 28th days of storage, dominant Vibrionaceae was accounting for 71.70%, 59.16%, and 70.68% of the total sequences analyzed, respectively. On the 14th and 35th days, Shewanellaceae was the dominant bacterial, accounting for 87.53% and 70.95% of the total sequences analyzed, respectively. In addition, 21st and 28th days, an abundance of Operational Taxonomic Units (OTUs) was top. The dominant bacterial of Proteobacteria, Firmicutes, was producer of biogenic amines. Furthermore, the analysis results of HPLC shown the total biogenic amines of maximum amount 363.01 mg/kg in the sample of HY.14 lower than 1000 mg/kg of the FDA regulation. The range ability of cadaverine was obvious following with the storage time. Cadaverine was 87.36 mg/kg on the 0th day, and it was maximum amount of 276.89 mg/kg on the 14th days. Putrescine was 20 mg/kg on the 0th day and maximum amount of 55.04 mg/kg on the 28thdays of storage. The tyramine was smallest amount of production, and the largest amount was 38.99 mg/kg on 28th, and the smallest amount was 11.97 mg/kg on 35th. Nevertheless, the maximum amount of histamine was 55.04 mg/kg on the 0th day and about 23.14 mg/kg of histamine was little change from 14th to 35th days of storage. Dominant bacteria affect the change of biogenic amines. The study can help understand the interaction between microbial flora and biogenic amines in the salted mackerel of one-night courtyard.

Reducing biogenic amine in seriflux and huangjiu by recycling of seriflux inoculated with Lactobacillus plantarum JN01

High content of biogenic amine (BA) in huangjiu could pose serious quality concerns. More than 71% of BA in huangjiu were carried over from seriflux (rice soaking wastewater), which were produced by some BA producing bacteria during rice soaking process. A BA non-producing strain, Lactobacillus plantarum JN01, was introduced to rice soaking process, which decreased BA content in seriflux by 93.8% by niche competition at bench scale. Recycling of seriflux inoculated with L. plantarum JN01 at pilot run scale for ten batches demonstrated that BA in seriflux and huangjiu were reduced by 78.4% and 87.7%, respectively. The safety of huangjiu was enormously improved without affecting on the profiles of flavor compounds. Our results demostrated that seriflux recycling technology could reduce 50% of water consumption and achieve "zero effluents" in rice soaking process, which might potentially be a "green technology" not only for huangjiu brewing industry, but also for other related traditional fermented food industries.

Analysis of microbiomes in three traditional starters and volatile components of the Chinese rice wines

To understand the effect of microbial community on the flavor of fermented rice wine, microbiomes in three traditional starters (CMQ, NBQ, and YCQ) from different origins for making Chinese rice wines were evaluated and the volatile components of their rice wines were compared. The results showed that the dominant genera in CMQ were Pantoea, Bacillus, Rhizopus, and Candida, the dominant microorganisms in NBQ were Pediococcus, Lactobacillus, Acetobacter, Weissella, Bacillus, Rhizopus, Candida, and Aspergillus, the dominant microorganisms in YCQ were Pediococcus, Lactobacillus, Leuconostoc, Weissella, Lactococcus, Ochrobactrum, Rhizopus, and Mucor. There were significant differences in sensory properties of the wines brewed by three starters. Although the major aroma components were benzyl alcohol, 2-octanone, benzoic acid, and phenethyl acetate, each rice wine had its own main aroma components include 1-octanol, 1-pentanol, ethyl acetate, etc. The results showed that the different microbial communities in starter results in the significant difference of the aroma components in its fermented rice wine.

Drinking tastes of Chinese rice wine under different heating temperatures analyzed by gas chromatography-mass spectrometry and tribology tests

Drinking tastes and lubrication properties of Chinese rice wine (CRW) under different heating temperatures were studied by tribology tests, gas chromatography-mass spectrometry (GC-MS) and sensory evaluations. CRW's drinking tastes were evaluated by taste panelists. Flavor compounds were detected by GC-MS. Lubrication properties of CRW were measured by tribometer. Drinking tastes changed under different heating temperatures and were the best at 60°C assessed by panelists. Four key compounds, furfural, benzaldehyde, butanedioic acid diethyl ester, and phenylethyl alcohol, were determined by GC-MS affecting drinking tastes of CRW. Their variation trends were consistent with the changes of CRW's tastes. The variation of CRW's lubrication properties had a positive correlation with that of CRW's taste, especially astringency. The lowest friction coefficient implied the best lubrication performance and taste at 60°C. Therefore, it was possible to rapidly evaluate drinking tastes of CRW using tribology technology based on the results. Reasons for temperatures influencing CRW's lubrication properties and drinking tastes were also analyzed in this study.

New insights into the impacts of huangjiu compontents on intoxication

Although huangjiu is a popular alcoholic beverage in China, the occurrence of quick-intoxication suppresses huangjiu consumption and impedes development of the huangjiu industry. In this study, the Cryprinus carpio intoxication model was used to compare the differences in intoxication effect of alcoholic beverages and to assess the impacts of huangjiu components on intoxication for the first time. Exposure to huangjiu led to the most rapid physical imbalance of C. carpio, followed by red wine and Western liquor. Higher alcohols, biogenic amines and aldehydes could cause physical imbalance of fish by themselves, and synergistic effects were observed when combined with ethanol. 2-Phenylethanoland and isopentanol had the greatest positive effect on huangjiu intoxication, followed by histamine and phenethylamine. No synergistic effect was observed between individual aldehydes and ethanol. Identification of these impactful huangjiu components provides a new perspective on the establishment of more rigorous control on the quality and flavor of huangjiu.

Phenotypic and Genotypic Identification of Bacteria Isolated From Traditionally Prepared Dry Starters of the Eastern Himalayas

Preparation of dry starters for alcohol production is an age-old traditional technology in the Eastern Himalayan regions of east Nepal, the Darjeeling hills, Sikkim, and Arunachal Pradesh in India, and Bhutan. We studied the bacterial diversity in 35 samples of traditionally prepared dry starters, represented by marcha of Nepal, Sikkim, the Darjeeling hills, and Bhutan, phab of Bhutan, and paa, pee, and phut of Arunachal Pradesh, respectively. Populations of bacteria in these starters were 105 to 108 cfu/g. A total of 201 bacterial strains were isolated from starter samples, phenotypically characterized, and their identities confirmed by the 16S rRNA sanger sequencing method. The dominant phylum was Firmicutes (85%), followed by Proteobacteria (9%), and Actinobacteria (6%). Lactic acid bacteria (LAB) (59%) formed the most abundant group, followed by non-LAB (32%) and Gram-negative bacteria (9%). Based on the 16S rRNA gene sequencing result, we identified LAB: Enterococcus durans, E. faecium, E. fecalis, E. hirae, E. lactis, Pediococcus acidilactici, P. pentosaceus, Lactobacillus plantarum subsp. plantarum, Lb. pentosus, Leuconostoc mesenteroides, and Weissella cibaria; non-LAB: Bacillus subtilis subsp. inaquosorum, B. circulans, B. albus, B. cereus, B. nakamurai, B. nitratireducens, B. pseudomycoides, B. zhangzhouensis, Kocuria rosea, Staphylococcus hominis subsp. hominis, S. warneri, S. gallinarum, S. sciuri, Lysinibacillus boronitolerans, Brevibacterium frigoritolerans, and Micrococcus yunnanensis; Gram-negative bacteria: Pseudomonas putida, Klebsiella pneumoniae, Enterobacter hormaechei subsp. xiangfangensis, E. hormaechei subsp. steigerwaltii, and Stenotrophomonas maltophilia. We characterized diversity indexes of the bacterial community present in traditionally prepared dry starters. This is the first report on the bacterial diversity of traditionally dry starters of the Eastern Himalayas by sanger sequencing.

Identification of a Lactic Acid Bacteria to Degrade Biogenic Amines in Chinese Rice Wine and Its Enzymatic Mechanism

A L. plantarum, CAU 3823, which can degrade 40% of biogenic amines (BAs) content in Chinese rice wine (CRW) at the end of post-fermentation, was selected and characterized in this work. It would be an optimal choice to add 106 cfu/mL of selected strain into the fermentation broth to decrease the BAs while keeping the character and quality of CRW. Nine amine oxidases were identified from the strain and separated using Sephadex column followed by LC-MS/MS analysis. The purified amine oxidase mixture showed a high monoamine oxidase activity of 19.8 U/mg, and more than 40% of BAs could be degraded. The biochemical characters of the amine oxidases were also studied. This work seeks to provide a better solution to degrade BAs in CRW prior to keeping the character and quality of CRW and a better understanding of the degradability of the strain to the BAs.

The use of next generation sequencing for improving food safety: Translation into practice

Next Generation Sequencing (NGS) combined with powerful bioinformatic approaches are revolutionising food microbiology. Whole genome sequencing (WGS) of single isolates allows the most detailed comparison possible hitherto of individual strains. The two principle approaches for strain discrimination, single nucleotide polymorphism (SNP) analysis and genomic multi-locus sequence typing (MLST) are showing concordant results for phylogenetic clustering and are complementary to each other. Metabarcoding and metagenomics, applied to total DNA isolated from either food materials or the production environment, allows the identification of complete microbial populations. Metagenomics identifies the entire gene content and when coupled to transcriptomics or proteomics, allows the identification of functional capacity and biochemical activity of microbial populations. The focus of this review is on the recent use and future potential of NGS in food microbiology and on current challenges. Guidance is provided for new users, such as public health departments and the food industry, on the implementation of NGS and how to critically interpret results and place them in a broader context. The review aims to promote the broader application of NGS technologies within the food industry as well as highlight knowledge gaps and novel applications of NGS with the aim of driving future research and increasing food safety outputs from its wider use.

Biogenic amines analysis and microbial contribution in traditional fermented food of Douchi

Biogenic amines (BAs) have been reported to threaten the Douchi safety, while the BAs formation mechanism and corresponding control method have not been clarified for Douchi. The present study aims to investigate the microbial contribution to BAs in Douchi, and to find the beneficial strain for BAs control. Firstly, the BAs profiles of 15 Douchi samples were analyzed, and common 6 kinds of BAs were detected from different samples. All the samples showed the total BAs contents within the safe dosage range, while the histamine concentrations in 2 samples and β-phenethylamine in 6 samples were above the toxic level. Then, the bacterial and fungal communities were investigated by high-throughput sequencing analysis, and Bacillus and Candida were identified as the dominant bacteria and fungi genus, respectively. Furthermore, nineteen strains were selected from the dominant species of Douchi samples, including 14 Bacillus strains, 2 Staphylococcus strains, 1 Enterococcus strain and 2 Candida strains, and their BAs formation and degradation abilities were evaluated. B. subtilis HB-1 and S. pasteuri JX-2 showed no BAs producing ability, and B. subtilis GD-4 and Candida sp. JX-3 exhibited high BAs degradation ability. Finally, fermented soybean model analysis further verified that B. subtilis HB-1 and S. pasteuri JX-2 could significantly reduce BAs. This study not only contributed to understanding the BAs formation mechanism in Douchi, but also provided potential candidates to control the BAs in fermented soybean products.

Suitability of various DNA extraction methods for a traditional Chinese paocai system

Traditional paocai brine (PB), which is continuously propagated by back-slopping and contains various species of lactic acid bacteria (LAB), is critical for the flavor of paocai. Culture-independent approaches are commonly used to investigate the microbial communities of fermented food. To evaluate the influence of different DNA (DNA) extraction methods on estimates of bacterial community profiles from 4 PBs, the lysis efficiency, DNA yield, purity and denaturing gradient gel electrophoresis (DGGE) profiles of V3 region of a 16S ribosomal ribonucleic acid gene were acquired. The cell lysis pattern of SDS + beads and Lysing matrix E+ beads (methods 3 and 4) showed higher cell lysis efficiency than SDS and SDS + Lysozyme (methods 1 and 2) in all PBs. SDS + beads obtained the largest DNA yield of the 4 methods. Moreover, methods 3 and 4 resulted in higher H' values and generated more global bacteria profiles than other methods. Overall, our results demonstrate that the properties of PB significantly affect the efficiency of DNA extraction methods. Methods 3 and 4 were both suitable for DNA extraction from PB. Method 3 is more economic, simple and rapid than method 4 for large-scale studies of the bacterial profiles of PB.

Next-generation sequencing approaches for improvement of lactic acid bacteria-fermented plant-based beverages

Plant-based beverages and milk alternatives produced from cereals and legumes have grown in popularity in recent years due to a range of consumer concerns over dairy products. These plant-based products can often have undesirable physiochemical properties related to flavour, texture, and nutrient availability and/or deficiencies. Lactic acid bacteria (LAB) fermentation offers potential remediation for many of these issues, and allows consumers to retain their perception of the resultant products as natural and additive-free. Using next-generation sequencing (NGS) or omics approaches to characterize LAB isolates to find those that will improve properties of plant-based beverages is the most direct way to product improvement. Although NGS/omics approaches have been extensively used for selection of LAB for use in the dairy industry, a comparable effort has not occurred for selecting LAB for fermenting plant raw substrates, save those used in producing wine and certain types of beer. Here we review the few and recent applications of NGS/omics to profile and improve LAB fermentation of various plant-based substrates for beverage production. We also identify specific issues in the production of various LAB fermented plant-based beverages that such NGS/omics applications have the power to resolve.

Innovation Chinese rice wine brewing technology by bi-acidification to exclude rice soaking process

As a traditional fermented alcoholic beverage of China, Chinese rice wine (CRW) had a long history of more than 5000 years. Rice soaking process was the most crucial step during CRW brewing process, because rice soaking quality directly determined the quality of CRW. However, rice soaking water would cause the eutrophication of water bodies and waste of water. The longer time of rice soaking, the higher the content of biogenic amine, and it would have a huge impact on human health. An innovation brewing technology was carried out to exclude the rice soaking process and the Lactobacillus was added to make up for the total acid. Compared to the traditional brewing technology, the new technology saved water resources and reduced environmental pollution. The concentration of biogenic amine was also decreased by 27.16%, which improving the security of the CRW. The esters increased led to more soft-tasted CRW and less aging time; the quality of CRW would be improved with less alcohol.

Insights into the Biogenic Amine Metabolic Landscape during Industrial Semidry Chinese Rice Wine Fermentation

Inspired by concerns about food safety, the metabolic landscape of biogenic amines (BAs) was elucidated during industrial semidry Chinese rice wine fermentation. The main fermentation process represented the largest contribution to BA formation, which corresponded to 69.1% (54.3 mg/L). Principal component analysis revealed that total acid and ethanol were strongly correlated with BAs, indicating that BA formation favored acidic and stressful conditions. Other than putrescine (PUT), spermidine (SPD), and spermine (SPM), 5 BAs exhibited strong relationships with the precursor amino acids (R² > 0.85). PUT was mainly decarboxylated from arginine (89.6%) whereas SPD (100%) and SPM (83.1%) were obtained from ornithine. Interestingly, some SPD could convert back to PUT (24.3%). All 8 BAs showed good relationships with lactic acid bacteria (LAB) (R² around 0.75). Moreover, among the five main LAB genera, Lactobacillus had a positive correlation with BA formation.