| Due to changes in eating habits,overwork fatigue and other reasons,human immunity has declined,and most people’s bodies are in a state of Suboptimal health,increasing the pressure on medical institutions.Therefore,new requirements have been put forward for the medical model,shifting from simple disease treatment to a combination of prevention,healthcare,treatment,and rehabilitation.Develop health drinks that are beneficial to human health.Jujubes are rich in nutrients,have the same medicinal and food sources,are abundant in resources,have obvious tonifying effects,and have minimal toxic and side effects.These obvious advantages are of great significance for the development of health food and drugs.This study will provide a theoretical basis for the study of the metabolic mechanism of jujube and other matrix foods fermented by adding a certain proportion of composite probiotics.This study used probiotics with microbial ecology to ferment jujube and wheat bran extracts.In order to better understand the changes of fermentation broth produced by probiotics in the fermentation process,we used high-throughput sequencing technology to study the changes of microbial community in the fermentation process;Analyze the changes in physicochemical properties,some bioactive substances,and in vitro antioxidant activity during the fermentation process;And through non targeted metabolomics analysis of fermentation broth at different fermentation stages,significant differential metabolites were screened for different fermentation stages,and annotation and metabolic pathway research were completed.The main research conclusions are as follows:(1)The fermentation broth of 0 d,2 d,7 d,14 d,28 d and 56 d(corresponding to A,B,C,D,E and F,respectively)was used to analyze the microbial community succession during fermentation using high-throughput sequencing,and the results of this study found that the community composition of microorganisms would change with the progress of fermentation.A total of 1438329 effective sequence numbers were obtained by bacteria in the 6 sets of samples.A total of 1719030 effective sequence numbers were obtained for fungi;from α Diversity analysis,the species diversity of bacteria showed an initial decrease followed by an increase,and then a decrease followed by a tendency to be relatively stable.The species diversity of fungi showed a decreasing trend first,then increasing and then plateauing.from β Diversity analysis.The succession of bacterial communities during fermentation can be divided into 4 stages.The succession of fungal communities during fermentation can be divided into 3 stages.Taxonomic profiling was available and a total of 29 phyla,426 genera were identified in the bacterial community structure.Among them the predominant bacterial phyla are Proteobacteria and Firmicutes.Acidococcus spp.,Ralstonia spp.,Lactobacillus spp.,and Acetobacter spp.A total of 6 phyla,68 genera were identified in the fungal community structure.The dominant fungal phyla among them are Ascomycota,Basidiomycota.Aspergillus spp.,Pichia spp.,Candida spp.By species composition analysis among LEf Se groups,the biomarkers of each stage of bacteria: Lactobacillaceae,bacillus,Firmicutes,Enterobacteriaceae,Enterobacteriaceae,Moraxella,Enterobacteriaceae,Acinetobacter,pseudomonadaceae were the group A biomarkers;Lactobacillaceae,Lactobacillus spp.,were the biomarkers of group B;Burkholderiaceae,Ralstonia spp.,proteus spp γ-Proteobacteria,xanthobacteriaceae,Rhizobium leguminosarum,Rhizobiaceae were the biomarkers of group E.Groups C,D,and f did not have any biomarker species;Biomarkers of fungal communities at different stages: Aspergillus flavus,lachnospiraceae,saccharomycetaceae,saccharomycetaceae were group A biomarkers;Saccharomycetales,Saccharomycetales,Pichiaceae,Pichia group B biomarkers;The phylum Ascomycota is a group D biomarker;Basidiomycetes are group E biomarkers.There were no obvious biomarker species in groups Cand F.(2)During fermentation,p H gradually decreased with the progress of fermentation and finally stabilized around 2.91;The content of titratable acids then increased gradually with the progress of fermentation,and then tended to be stable up to 105.36 mg/m L;Overall,the concentrations of total sugars and reducing sugars decreased gradually as the fermentation progressed,with a moderate increase in the middle,and the concentrations at steady state were 2.09 mg/m L and 1.28 mg/m L,respectively.The total flavonoid concentration showed a first decreasing and then slowly increasing trend during fermentation,and was in a decreasing trend at 0-14 d,with the lowest total flavonoid concentration at 0.125 mg / m L and a stepwise increase at 14-56 d,with a final concentration at 0.1785 mg / m L;The total phenolic concentration showed an initial increase and then maintained a relative stability,with a final total phenolic concentration of 0.3692 mg / m L;Among the detected amino acids,except proline,all decreased to various degrees with the progress of fermentation;Sodium,magnesium,potassium,calcium and zinc were increased compared with those before fermentation,while iron decreased back after increasing in the middle of fermentation;During the fermentation process,the antioxidant changes in vitro were in a similar pattern,while the reducing power,DPPH radical scavenging ability,superoxide radical scavenging ability,from the whole fermentation process,were first increased to maintain a stable change trend with 40.22%,101.01%,and 174.87%,respectively,at 56 d of fermentation compared with before fermentation.(3)A nontargeted metabolomics approach was used to profile the metabolites during the fermentation of the samples that had been fermented for 0 d,2 d,7 d,14 d,28 d and 56 d(corresponding to A,B,C,D,E and F,respectively),and 352 significant differential metabolites(VIP value > 1,FC > 1.5 or FC < 0.667,and P value < 0.05)were identified in the different fermentation stages,including organic acids,PK polyketones,peptides,amino acid related compounds and other substances;Moreover,the top 50 differential metabolites with large effects on the fermentation process were mostly enriched at 56d;From the screening and classification of differential metabolites at different fermentation stages,it can be seen that with longer fermentation time,the differential metabolite reduction marks that the fermentation has approached maturity,and the components of the fermentation broth become relatively stable.A total of 128 pathways were enriched in the whole fermentation process,and the KEGG pathways with significant top30 enrichment were analyzed,among which the top key pathways were biosynthesis of amino acids,cysteine and methionine metabolism,alanine,aspartate and glutamate metabolism,digestion and absorption of proteins,and ABC transporters. |
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