Tolerance of Lactic Acid Bacteria Strains for Phytoprotein Yoghurt Fermentation to Simulated Gastrointestinal Environments

Previous studies have revealed that Lactobacillus plantarum FJAT-7926and Lactobacillus casei FJAT7928are promising fermentation agents for phytoprotein yoghurt beverage.The aim of our study was to examine the tolerance differences of the two strains under artificial gastric juice with different pH values and artificial intestinal juice containing different concentrates of bile salt and trypsin.The results showed that both of them have high tolerance responses to low pH value.When incubated in artificial gastric juice with pH3.0for 4h, survival of each tested strain was over 1×108cfu·mL-1 with a survival rate of 56.06%and 55.65%, respectively.However, the survival of them declined to 1×105cfu·mL-1 when incubated in the juice with pH2.0for 2h, and remained at concentrations of 3.67×102 cfu·mL-1 and 2.30×103 cfu·mL-1 in incubation for 4h.Our results suggest that both of the tested strains have great tolerance to the artificial intestinal juice.Though the survival rate of FJAT7928and FJAT-7926decreased as the concentration of bile salt increased, the concentrates of the both strains kept in the same order of magnitude.After 4hincubation in the artificial intestinal juice containing 0.3% or 0.5% bile salt, the survival rates for FJAT-7926and FJAT-7928were more than 70% and 40%, respectirely.The above indicated that both FJAT-7926and FJAT-7928have high tolerance to simulated gastrointestinal environments and both of them have broad prospects in the application of fermentation of phytoprotein yoghurt beverage.