Characterization And Product Development Of Lactobacillus Helveticus H11 In Fermented Soymilk

Fermented soy milk is favored by consumers for its unique health benefits.However,the development of fermented soybean milk is severely restricted due to its poor stability,thick bean smell and serious acidification during storage.Therefore,in this paper,and a Streptococcus thermophilus S10 with good fermentation characteristics in soy milk were separated from the yoghurt samples in Yili Prefecture,Xinjiang,and fermented in soy milk by single strain and two strains,while the commercial starter(inoculation amount is0.003%)was used as the control.The effects of Lactobacillus helveticus H11 on fermentation quality of fermented soybean milk were investigated by evaluating the p H,titrated acidity,ACE inhibition activity,content of free soybean isoflavone,physical properties and sensory evaluation during storage.Since the indexes of fermented soy milk samples from four groups were the best at the 7th day of storage,non-targeted metabolomics technology was used to analyze the metabolites of samples from four groups at the 7th day of storage,and key metabolites with significant differences were screened out by multivariate statistical method,and their functional properties were further studied.To comprehensively evaluate the application potential of Lactobacillus helveticus H11 in fermented milk.The results are as follows:(1)The fermentation time of Lactobacillus helveticus H11 combined with Streptococcus thermophilus S10 was significantly reduced(P<0.05),and the fermentation time was 6.04±0.05h,which was the shortest among the four groups.During storage,S10+H11 complex group had suitable acidity,fine tissue,good viscoelasticity,high sensory scores and high viable bacteria count.At the end of storage,the S10+H11combination group had a viable bacterial count higher than 10~8CFU/m L,thus ensuring its effective probiotic efficacy.(2)During storage,the fermented milk added with Lactobacillus helveticus H11had high ACE inhibitory activity,among which the S10+H11 compound fermentation group had the highest ACE inhibitory activity(54.30±0.380%)when stored for 7 days,and the ACE inhibitory peptide VPP and IPP content were the highest(0.47±0.007μmol/L)and(0.16±0.023μmol/L),respectively.(3)The results of non-targeted metabolic group showed that metabolites of fermented soy milk samples in four groups were significantly different(P<0.05)after 7days of storage,mainly consisting of isoflavones,saponins,organic acids,amino acids and other substances.The main metabolic pathways of linoleic acid and C5-branched dibasic acid were different metabolic pathways.From the metabolic point of view,the compound fermented soy milk produced by Lactobacillus helveticus H11 and Streptococcus thermophilus S10 has more abundant metabolites,more unique flavor and probiotic characteristics.In summary,the combined fermentation of Lactobacillus helveticus H11and Streptococcus thermophilus S10 could improve the fermentation characteristics,storage stability,ACE inhibitory activity and sensory quality of fermented soy milk.This study was able to provide a test for Lactobacillus.The industrial promotion and application of Lactobacillus helveticus H11 and functional dairy products provide theoretical data support.