Effects of Soybean Protein Isolates and Soybean Peptides on Growth and Metabolism of Lactobacillus rhamnosus GG

To investigate the effects of nitrogen source nutrients on the growth and metabolism of Lactobacillus rhamnosus GG (LGG), this study used soybean protein isolates (dSPI) and soybean peptides (dPEP) from simulated gastrointestinal digestion as raw materials. The number of viable cells and the production of lactic acid and acetic acid in LGG were measured through mono-culture. LGG was co-cultured with Listeria monocytogenes to determine its utilization of soybean protein isolates and soybean peptides in the presence of pathogens. The results of mono-culture showed that both dPEP and dSPI could increase the viable number of LGG (P<0.05), and the effect of dPEP was earlier four hours than that of dSPI, and they could significantly increase the production of SCFAs (P<0.05). In the co-culture system, dSPI weakened the competitiveness of Listeria monocytogenes (List m) and improved the competitiveness of LGG. After 4 h and 8 h of culture, the number of living cells of LGG was higher than that of mono-culture (P<0.05). The results of this study identify nitrogen sources as potentially beneficial nutrients, and provide a theoretical basis for the development of soybean protein and soybean peptide functional foods.