Study On The Effect Of Fermented Milk And Soymilk As Carriers On The Tolerance Of Probiotics To Gastrointestinal Fluid

In order to enhance the tolerance of probiotics to gastroenteric fluid and improve the survival rate of probiotics,milk and soymilk are often used as carriers when consuming probiotics.However,the effectiveness of the two vectors may differ for different strains of probiotics.In this experiment,Lactobacillus plantarum LP-6 was taken as the research object,soymilk and milk were used as raw materials for fermentation,and dynamic biomimetic digestive system was used to carry out in vitro digestion of fermented milk with different raw materials,so as to explore the survival rate of Lactobacillus plantarum LP-6 in the stomach under different carriers,and metabolomics technology was used to analyze the protective effect of probiotics under different carriers.At the same time,a Lactobacillus plantarum LP-6 fermented milk product was prepared by using Lactobacillus plantarum LP-6 and starter culture PYS-010 based on the optimal carrier.The specific results are as follows:The results showed that the survival rate of Lactobacillus plantarum LP-6 in fermented soymilk was significantly higher than that in fermented soymilk,indicating that fermented soymilk had a better protective effect on Lactobacillus plantarum LP-6 during digestion.The metabolites of fermented milk and soymilk at different digestion times were studied.The results showed that the metabolites of fermented soymilk at different digestion times were significantly different.These differential metabolites include amino acids and derivatives,organic acids,carbohydrates and other substances.It mainly involves several complex metabolic pathways such as galactose metabolism,starch and sucrose metabolism,glutathione metabolism,aminoacyl-t RNA biosynthesis,glycolysis and so on.Aspartic acid and its derivatives were significantly up-regulated in the whole digestion process of soymilk,so it was speculated that the accumulation of aspartic acid and its derivatives in fermented soymilk improved the tolerance of Lactobacillus plantarum LP-6 in the stomach,so that it could maintain a high activity at a low p H environment.Lactobacillus plantarum LP-6 fermented milk was developed from soymilk.The fermentation time of complex fermented milk(LP-6+PYS-010)was shorter and the curd was faster than that of LP-6 and PYS-010 alone,and the p H value,titrated acidity,viable bacteria count and viscosity of complex fermented milk were significantly different from those of the other two groups during storage(P < 0.05).In sensory evaluation,the products in LP-6+PYS-010 complex fermentation group had uniform color,high viscosity,moderate tissue status,and no bad taste,and the evaluation score was significantly higher than that in the other two groups(P < 0.05).In conclusion,the survival rate of Lactobacillus plantarum LP-6 in fermented soymilk is better,which is conducive to the play of its probiotic effect.The study provides a theoretical basis for the application of Lactobacillus plantarum LP-6 in fermented soymilk.