Study On The Quality And Bacterial Microbial Diversity In Three Fermentation Methods For Citrus Fruit Vinegar

In this study,citrus is used as the experimental material.The chemical co mponents and flavors of solid state fermentation(SSF),liquid surface fermentat ion(LSF),and liquid deep fermentation(LDF)citrus fruit vinegar To study th e substance and compare the differences in the quality of fruit vinegar in three fermentation methods;study the bacterial microbial diversity to understand the differences in species abundance,diversity,community composition and cluster ing of the three fermentation methods;reveal the diversity and diversity of bac terial communities Correlation between chemical composition and volatile flavor substances.This has certain reference significance for improving the quality of fruit vinegar,improving the comprehensive utilization rate of raw materials,pr oviding theoretical and technical support,and promoting the development of fru it vinegar industrialization.(1)The changes in the total acid content of citrus fruit vinegar in the thr ee fermentation methods are basically the same,all of which show a trend of rising first and then stable,but the fermentation cycle is different,the solid sta te fermentation is the longest,the liquid deep fermentation is the shortest,and the liquid surface fermentation is in between.(2)Six kinds of organic acids were detected in citrus fruit vinegar,namel y citric acid,malic acid,tartaric acid,succinic acid,oxalic acid and lactic acid;different fermentation methods,the same type of organic acid but different co ntent,the content order is solid fermentation> Liquid surface fermentation> Liq uid deep fermentation;solid fermentation and liquid surface fermentation have higher citric acid,malic acid,and tartaric acid content,and liquid deep ferment ation has higher succinic acid,citric acid,malic acid,and tartaric acid content.(3)Three fermentation methods of citrus fruit vinegar Total phenol content solid fermentation> liquid surface fermentation> liquid deep fermentation;total flavonoid content liquid surface fermentation> liquid deep fermentation> solid fermentation;total phenol and total flavonoid content change trend in the ferm entation process Both are in the early stage of fermentation> middle stage> late stage.(4)10 kinds of monophenols were detected in citrus fruit vinegar,namely gallic acid,catechins,epicatechin,chlorogenic acid,caffeic acid,p-coumaric a cid,ferulic acid and quercetin,Rutin and resveratrol;different fermentation met hods,the same type of monophenolic substance but different content.The orde r of content is solid fermentation> liquid fermentation.The content of gallic ac id,catechins and quercetin in solid fermentation is higher,and the content of catechins and quercetin in liquid fermentation is higher.(5)The order of total amino acid content and essential amino acid content in the three fermentation methods of citrus fruit vinegar are solid fermentatio n> liquid surface fermentation> liquid submerged fermentation;the three ferme ntation methods of citrus fruit vinegar all contain flavored amino acids;solid f ermentation of citrus The nutritional value of fruit vinegar amino acid is highe r than that of liquid fermented fruit vinegar.2.Research on three fermentation methods of volatile flavor compounds of citru s fruit vinegar(1)Citrus fruit vinegar with three fermentation methods detected a total of188 volatile flavor substances,including 49 esters,29 alcohols,8 acids,9 ket ones,7 aldehydes,and 37 olefins Species,40 species of benzene ring and 9 s pecies of other species;the types and mass concentration of volatile flavor sub stances in solid fermentation are higher than those in liquid surface fermentatio n and liquid deep fermentation;the three fermentation methods are the mass c oncentration fermentation of volatile flavor substances in the fermentation proce ss Later period is higher than early period.(2)The main components of volatile flavor substances in citrus fruit vineg ar are esters,alcohols and acids,with high mass concentration,which is the m ain contributor to citrus fruit vinegar flavor substances;ketone aldehydes,olefin s,benzene ring The compounds have a relatively low mass concentration and a low contribution rate to citrus fruit vinegar flavor substances.(3)In the principal component analysis,the volatile flavor substances of the liquid surface and liquid deep fermentation of citrus fruit vinegar are not much different,but there is a big difference from the solid fermentation.The co mpounds that contribute to solid state fermentation are ethyl acetate,ethyl nona noate,ethyl caprate,butyl 3-methyloctanoate,acetaldehyde,butyric acid and iso butyl acetate.The compounds contributing to the liquid surface fermentation an d liquid deep fermentation are ethyl 9-decenoate,cyanomethane,ethyl linoleate,2-undecanone,isobutyl n-decanoate,4-dimethylbenzene Compounds such as for maldehyde,ethyl 4-acetoxybutyrate and 2-hexene-1-ol acetate.3.Research on three fermentation methods of citrus fruit vinegar bacterial micro organisms(1)The fermentation methods of citrus fruit vinegar are different,the relat ive abundance and diversity of species also have certain differences,and they show dynamic changes during the fermentation process.Three fermentation met hods Citrus fruit vinegar species number Liquid deep fermentation> Solid state fermentation> Liquid surface fermentation,Species diversity solid fermentatio n> Liquid deep fermentation> Liquid surface fermentation.(2)At the phylum level,the dominant phylum of solid-state fermentation are Proteobacteria and Cyanobacteria.The dominant phylum of liquid surface a nd liquid deep fermentation are Proteobacteria.Acetobacter and Tobacco,the d ominant bacteria on the liquid surface and liquid deep fermentation are Acetob acter.(3)The bacterial microorganisms at the three citrus fruit vinegar gate leve ls can be divided into four categories by clustering heat maps,and the sample structure is similar in the early and middle stages of the fermentation process.(4)According to the correlation analysis of environmental factors,the bact erial microorganisms of citrus fruit vinegar have the largest correlation with or ganic acids and volatile flavor substances,followed by amino acids,and the lo west correlation between phenols,total phenols and total flavonoids.