| The characteristics of the traditional Suanzhayuare not only has the sour and fragrance,endless aftertaste,strange flavor,long-term storage,etc,but also the bones ready to eat,which is popular with the public.In this paper,the commercial Suanzhayu was taken as the research object.After determining the biochemical indicators of the product,the starter suitable for industrial production of Suanzhayu was selected.Enzyme-Lactobacillus combination technology was used to improve the quality of Suanzhayu.This topic was mainly studied the following aspects:The commercially available Suanzhayu(Guizhou and Hunan Provinces)was used as the research object,the p H,salinity,organic acid,free amino acid,biogenic amine,microbial bacterial community and volatile compounds of the eight kinds of Suanzhayu were detected.The results showed that,the dominant bacteria in the phylum level were Firmicutes,Lactobacillus and Tetragenococcusat the genus level by 16 S r DNA sequencing.The p H ranged from 4.30 to 6.20,the content of lactic acid was 1.50 to 4.00%,and the salinity ranged from 5.50 to 8.00% at eight species of Suanzhayu.The content of free amino acids was determined by liquid chromatography,and the content of fresh amino acids(Asp and Glu)in place of Guizhou origin was found.It was higher thaninplace of Hunan origin.The volatile compounds in Suanzhayu were detected by headspace solid phase microextraction-gas chromatography-mass spectrometry(GC-MS).A total of 7 compounds were detected,including aldehydes,ketones,aldehydes,hydrocarbons,esters,acids and others.Among them,the hydrocarbons and alcohols in Guizhou originated more than the Hunan.And histamines from eight Suanzhayu did not exceed the FDA limit.This indicating that the marketed Suanzhayu the product was safe,at the same time,the quality of the Suanzhayu between different producing areas was greatly affected by factors such as raw materials,processing technology and fermentation time.Through the evaluation of acid production and acid tolerance of 12 strains of lactic acid bacteria screened from fermented food,a lactic acid bacteria that can produce acid and acid tolerance was screened out.Enzyme-Lactobacillus combination technology was used to improve Suanzhayu.The 16 S r DNA sequencing was used to investigate the changes of microbial flora in different time of Suanzhayu,and the quality of fermented Suanzhayu under different conditions was detected.The results showed that in the four experimental groups,the dominant genus was Acinetobacter,at the initial stage of fermentation,was Lactococcus and staphylococcus appeared during the fermentation process.The dominant genus of the fermentation was Lactobacillus;p H increased with fermentation timeandhad a downward trend,the total acid content was negatively correlated with p H,and the water activity decreased with the prolongation of fermentation time.The TCA-soluble peptide gradually increased.After 28 days of fermentation,the content of the enzyme group and the EnzymeLactobacillus combination group was higher than thatthe single bacteria group and control group.GC-MS detected the increase of esters in four groups of volatile compounds in the Enzyme-Lactobacillus combination group.It was speculated from Pearson correlation that Lactobacillus,Weissella,Lactococcus,Acinetobacter,and Morganella and 18 volatile compounds,such as 3-methyl-1-butanol,1-heptanol,phenylethanol,cyclopentadecanol and 1-octene,were positively correlated with the control group.The content of the volatile compounds 3-methyl-1-butanol,1-heptanol,phenylethyl alcohol,cyclopentadecanol,1-octene,etc.of the Suanzhayu in the Enzyme-Lactobacillus combination group was higher.Combined with the above research results,it can be seen that the selected Lactobacillus plantarum can be used for the industrial production of Suanzhayu,and EnzymeLactobacilluscombination technology can improve the quality of Suanzhayu,and provide a solid theoretical basis for the realization of delicious and safe industrial production of Suanzhayu. |
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