Microbiomics and metabolomics insights into the microbial regulation on the formation of flavor components in the traditional fermentation process of Chinese Hongqu aged vinegar

This study aimed to investigate microbial succession and metabolic dynamics during the traditional fermentation of Hongqu aged vinegar,and explore the core functional microbes closely related to the formation of flavor components.Microbiome analysis demonstrated that Lactobacillus,Acetobacter,Bacillus,Enterobacter,Lactococcus,Leuconostoc and Weissella were the predominant bacterial genera,while Aspergillus piperis,Aspergillus oryzae,Monascus purpureus,Candida athensensis,C.xylopsoci,Penicillium ochrosalmoneum and Simplicillium aogashimaense were the predominant fungal species.Correlation analysis revealed that Acetobacter was positively correlated with the production of tetramethylpyrazine,acetoin and acetic acid,Lactococcus showed positive correlation with the production of 2-nonanone,2-heptanone,ethyl caprylate,ethyl caprate,1-hexanol,1-octanol and 1-octen-3-ol,C.xylopsoci and C.rugosa were positively associated with the production of diethyl malonate,2,3-butanediyl diacetate,acetoin,benzaldehyde and tetramethylpyrazine.Correspondingly,non-volatile metabolites were also detected through ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.A variety of amino acids and functional dipeptides were identified during the traditional brewing of Hongqu aged vinegar.Correlation analysis revealed that Lactobacillus was significantly associated with DL-lactate,indolelactic acid,D-(+)-3-phenyllactic acid,pimelic acid,pregabalin and 3-aminobutanoic acid.This study is useful for understanding flavor formation mechanism and developing effective strategies for the suitable strains selection to improve the flavor quality of Hongqu aged vinegar.

Health-promoting microbes in traditional Vietnamese fermented foods:A review

Vietnam has a long history of numerous traditional fermented products that contain a range of microorganisms with favorable technological,preservative,and organoleptic properties for food processing as well as other functional properties.This review emphasizes the most common traditional Vietnamese fermented foods and their beneficial indigenous bacteria having health-promoting effects.

Fermentation Production of Ganoderma lucidum by Bacillus subtilis Ameliorated Ceftriaxone-induced Intestinal Dysbiosis and Improved Intestinal Mucosal Barrier Function in Mice

Objective This study aimed to develop a type of Ganoderma lucidum(G.lucidum)-probiotic fermentation broth that can effectively improve the intestinal mucosal barrier function of mice with ceftriaxone-induced intestinal dysbiosis.Methods By means of absorbance of optical density(OD)value and phenol-concentrated sulfuric acid measurement of polysaccharide content,the probiotic species can grow on the medium of G.lucidum were screened out,and the concentration of the medium of G.lucidum was determined,and the fermentation broth was prepared for subsequent experiments.Thirty-two SPF grade male BALB/c mice were randomly divided into four groups(eight mice in each group),namely control group(CON),intestinal mucosal barrier damage model group(CS),fermentation broth intervention group(FT)and G.lucidum medium intervention group(GL),respectively.The intestinal dysregulation model was induced by intra-gastric administration of 0.2 mL ceftriaxone sodium(twice a day for seven consecutive days).From day 8,the FT group and GL group were gavage with 0.2 mL fermentation broth and G.lucidum medium,respectively.On day 15,all mice were sacrificed.To draw the weight curve and measure the cecal index;pathological examination of colon tissues with HE staining;serum levels of LPS,IL-10,TNF and IL-6 were detected by ELISA.Flow cytometry was used to analyze the changes of CD3+T cells,CD4+T cells,CD8+T cells and macrophages in spleen.16S rRNA sequencing was performed to detect the intestinal microbiota structure of mice.Results Bacillus subtilis can decompose and utilize G.lucidum fruiting body medium,and the suitable concentration of G.lucidum fruiting body medium is 33.2 mg/mL.The effect of Bacillus subtilis-G.lucidum fermentation broth on the damage of intestinal mucosal barrier caused by ceftriaxone sodium was reduced,the body weight of mice recovered and colon swelling improved,colon histopathological injury was alleviated,inflammatory cell infiltration was alleviated,serum IL-10 increased significantly,LPS、TNF-αand IL-6 decreased significantly compared with model group,and the proportion of T cells and intestinal dysbiosis was improved.Conclusions The experimental results suggest that Bacillus subtilis-G.lucidum fermentation broth can effectively improve the intestinal barrier function damage,immune dysfunction and intestinal dysbiosis caused by antibiotic overdose,and has a certain regulatory effect on intestinal mucosal barrier function.

Biogenic Amines Profile of Serbian Traditional Sausage in Relation to Raw Material and Production Conditions

Petrovska klobasa is a traditional dry fermented sausage produced in the Autonomous Province of Vojvodina. Formation of nine hiogenic amines was determined in three sausage groups produced from hot deboned （A1） and cold meat （B1, B3） during drying and ripening in traditional room （A1, B1） and in industrial ripening chamber （B3）. Dansyl chloride derived amines were analysed by high-performance liquid chromatography with diode-array detector （HPLC-DAD） on Eclipse XDB-C18 column. Histamine, the most important amine from food safety point of view, was not found in any of the analyzed samples. Serotonin and spermidine were also not detected in any samples, while spermin was determined in all analyzed samples. At the end of drying, phenylethylamine was the predominant amine in A1 sausage group （51.6 mg/kg）, and tryptamine in B1 （38.1 mg/kg） and B3 （28.7 mg/kg） sausage groups. At the end of ripening, tryptamine was the predominant biogenic amine in all sausage groups （133, 121 and 39.8 mg/kg in A1, B1 and B3 groups, respectively）. Total level of biogenic amines in all investigated sausages did not exceed 174 mg/kg at the end of drying and 238 mg/kg at the end of ripening period. Tryptamine and cadaverine may be used as indicators of total biogenic amines for sausages produced in traditional and indusrial conditions from hot deboned and cold meat.

Development of Starter Culture for the Production of African Condiments and Seasoning Agents

As a process, food fermentation dates back at least 6000 years and is likely to be derived from microbial interactions of an appropriate nature. Fermentation has allowed our ancestors to survive the winter season in temperate and cooler regions and those in the tropics to survive the periods of drought by improving food shelf-life and safety. Traditional fermentation process is still used as a replacement where there is no refrigeration or other means available for food storage. In general, fermented foods can be defined as foods produced through controlled microbial growth and the conversion of food components through enzymatic actions. They are generally appreciated for characteristics such as pleasant taste, aroma, texture and improved cooking and processing properties. Microorganisms contribute to the development of characteristic properties such as taste, smell, visual appearance, texture, shelf-life and protection by virtue of their metabolic activities. Enzymes indigenous to the raw materials may play a role in enhancing these characteristics. The use of starter cultures is a hallmark of industrial food fermentation and their introduction has been followed by a continuous search to improve them. Examples of desired properties in starter cultures include robustness during manufacturing, fast growth, high biomass yield and product yield and specific organoleptic properties. Quality, safety and acceptability of traditional fermented foods may be significantly improved through the use of starter cultures selected on the basis of multifunctional considerations, also taking into account the probiotic concept and possibilities offered for improved health benefits. Focused studies toward the introduction of starter cultures for small-scale fermentations seem more than justified, and in fact, deserve the highest priority.

Application of Antimicrobial Bacillus subtilis Strain as a Starter Culture to Improve Qualities and Safety of Fermented Soybean (SIENG) Produced in Cambodia

Fermented foods play a very important role in Cambodian health and nutrition,as well as other developing countries where food preservation methods may be limited.SIENG,a Khmer fermented soybean product,naturally contains both beneficial and pathogenic microorganisms.Traditional fermentation that relies on natural microbial flora and environmental conditions results in variable product quality and can lead to spoilage.A starter culture such as Bacillus subtilis can ensure the safety and stability of the products.The objective of this study is to control the growth of Gram positive pathogens contaminated into traditional fermented soybean(SEING)by using antimicrobial Bacillus subtilis isolated from the same kind of food.Out of 120 SIENG samples,49 B.cereus strains were isolated,and 12 of B.cereus were positively synthesized compared with the lyophilized control enterotoxin.Two of these strains(BTM8-7 and BTM8-8)produced high levels of enterotoxin.We identified five Bacillus strains with the ability to fight against indicator pathogenic microorganisms.Among the five strains,B.CeM6-2 had the highest activity level against Lactobacillus plantrum ATCC 8014 and the largest diameter.B.CeM6-2 tolerated up to 20 h at 30℃ and 22 h at 37℃.In testing the strains with PK and PK-PMSF enzymes,bacteriocin produced by the strain B.CeM6PK untreated and B.CeM6-2PK-PMSF had a significantly stronger ability to suppress all the pathogenic indicators from 0 h to 47 h compared to the B.CeM6-2PK.Moreover,CeM6-2 outperformed the Miyagino strains,as it actively produced bacteriocin that fought against all four indicator strains of Gram positive and lactic acid groups,especially against Listeria monocytogenes,Streptococcus pyrogene,Leuconostoc mesenterids and L.plantarum,from 0 h-58 h and 0 h-40 h at 35℃.CeM6-2(1%)strain had the highest ability to fight against B.cereus at 24 h and at 34 h to 44 h incubation as well.CeM6-2(10:0 mL)and CeM6-2(9:1 mL)have the strongest ability to fight against B.cereus at room temperature(48 h and 72 h).The longer incubation and time at room temperature produce the highest level of bacteriocin.Thus,bacteriocins produced by B.CeM6-2 can be used as a preservative in food processing industries to avoid food spoilage even in higher temperatures and time.

Insights into the microbial diversity and community dynamics of Chinese traditional fermented foods from using high-throughput sequencing approaches

Chinese traditional fermented foods have a very long history dating back thousands of years and have become an indispensable part of Chinese dietary culture. A plethora of research has been conducted to unravel the composition and dynamics of microbial consortia associated with Chinese traditional fermented foods using culture- dependent as well as culture-independent methods, like different high-throughput sequencing （HTS） techniques. These HTS techniques enable us to understand the relationship between a food product and its microbes to a greater extent than ever before. Considering the importance of Chinese traditional fermented products, the objective of this paper is to review the diversity and dynamics of microbiota in Chinese traditional fermented foods revealed by HTS approaches.