The survival ability of lactic acid bacteria(LAB)in the gastrointestinal tract is low,and the mechanism of LAB resistance to the gastrointestinal tract’s harsh environment is unclear.Therefore,this study used simulat...The survival ability of lactic acid bacteria(LAB)in the gastrointestinal tract is low,and the mechanism of LAB resistance to the gastrointestinal tract’s harsh environment is unclear.Therefore,this study used simulated gastrointestinal juices in vitro and transcriptomics approaches to identify proteins in Lactobacillus acidophilus CICC6074 that can enhance the strain’s tolerance to gastrointestinal juices and verify the function of the target proteins.The results showed that the survival rate of Lactobacillus acidophilus CICC6074 was 79.24%after 6 h of in vitro intestinal juice treatment,and there were 10 genes coding proteins with significant changes in expression,among which S-layer protein gene slpX was significantly up-regulated.After overexpression of the slpX gene,the survival rate of Lactobacillus acidophilus CICC6074 was 94.35%after 6 h of in vitro intestinal juice tolerance.In conclusion,the SlpX protein plays a crucial role under the simulated intestinal juice condition of Lactobacillus acidophilus CICC6074.This study provides a basis for a deeper understanding of the survival mechanisms of Lactobacillus acidophilus in the gastrointestinal tract.展开更多
The primary objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus 6074 on the nutrient transformation and quality characteristics of jujube juice.The screened L.acidophil...The primary objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus 6074 on the nutrient transformation and quality characteristics of jujube juice.The screened L.acidophilus 6074 with acid and bile salt resistance was used to ferment jujube juice,and the sensory properties and nutrient biotransformation of the fermented product were comprehensively evaluated.The results showed that the acid and bile salt resistance of L.acidophilus 6074 were 94.06%and 84.56%,respectively,and the viable counts after fermentation reached 8.75 lg CFU/mL.Total sugar and polysaccharide content decreased after fermentation,while total flavonoids,cAMP and triterpenoic acid increased significantly,as did organic acids and free amino acids(p<0.05).Moreover,the L.acidophilus 6074 fermentation reduced the molecular weight of the main polysaccharide component from 746,111.957 Da to 573,809.851 Da,and its microstructure changed.A total of 62 volatile compounds were identified in fermented jujube juice,among which acids were the highest,followed by esters.Particularly,L.acidophilus 6074 fermentation increased the content of phenylethyl acetate and lactic acid,generating new substances clopenthixol and phenylethyl alcohol of jujube juice.Sensory evaluation indicated that L.acidophilus 6074 fermentation improved the coloration of jujube juice and increased the overall acceptability of the fermented product.This study will provide theoretical basis and technical support for the industrial production of probiotic fermentation jujube juice related products.展开更多
基金supported by the National Natural Science Foundation of China(32272339,31972048).
文摘The survival ability of lactic acid bacteria(LAB)in the gastrointestinal tract is low,and the mechanism of LAB resistance to the gastrointestinal tract’s harsh environment is unclear.Therefore,this study used simulated gastrointestinal juices in vitro and transcriptomics approaches to identify proteins in Lactobacillus acidophilus CICC6074 that can enhance the strain’s tolerance to gastrointestinal juices and verify the function of the target proteins.The results showed that the survival rate of Lactobacillus acidophilus CICC6074 was 79.24%after 6 h of in vitro intestinal juice treatment,and there were 10 genes coding proteins with significant changes in expression,among which S-layer protein gene slpX was significantly up-regulated.After overexpression of the slpX gene,the survival rate of Lactobacillus acidophilus CICC6074 was 94.35%after 6 h of in vitro intestinal juice tolerance.In conclusion,the SlpX protein plays a crucial role under the simulated intestinal juice condition of Lactobacillus acidophilus CICC6074.This study provides a basis for a deeper understanding of the survival mechanisms of Lactobacillus acidophilus in the gastrointestinal tract.
基金supported by The Key R&D Program of Shaanxi Province,China(2023-ZDLNY-43).
文摘The primary objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus 6074 on the nutrient transformation and quality characteristics of jujube juice.The screened L.acidophilus 6074 with acid and bile salt resistance was used to ferment jujube juice,and the sensory properties and nutrient biotransformation of the fermented product were comprehensively evaluated.The results showed that the acid and bile salt resistance of L.acidophilus 6074 were 94.06%and 84.56%,respectively,and the viable counts after fermentation reached 8.75 lg CFU/mL.Total sugar and polysaccharide content decreased after fermentation,while total flavonoids,cAMP and triterpenoic acid increased significantly,as did organic acids and free amino acids(p<0.05).Moreover,the L.acidophilus 6074 fermentation reduced the molecular weight of the main polysaccharide component from 746,111.957 Da to 573,809.851 Da,and its microstructure changed.A total of 62 volatile compounds were identified in fermented jujube juice,among which acids were the highest,followed by esters.Particularly,L.acidophilus 6074 fermentation increased the content of phenylethyl acetate and lactic acid,generating new substances clopenthixol and phenylethyl alcohol of jujube juice.Sensory evaluation indicated that L.acidophilus 6074 fermentation improved the coloration of jujube juice and increased the overall acceptability of the fermented product.This study will provide theoretical basis and technical support for the industrial production of probiotic fermentation jujube juice related products.
