soybean peptide on the growth and activity of lactobacillus

In the experiment,the soy peptides (A and B) of two different degree of hydrolysis were added to the yo- ghurt fermentation as fermentation accelerator.Researches on the growth and the acid production of lactobacillus were processed.The vitality of lactobacillus in the samples was also tested in the experiment,for analyzing the influences of soy peptide on the lactobacillus vitality maintaining. The experiment was done with one single Lactobacillus acidophilus and two types fermentation media (MRS medium and skim milk).Fermentation media were made different by using soy peptides take part or whole of organic nitrogen in the MRS medium,and adding different amount of soy pepfides (peptide A and B peptide) to the media.The fermentation of lactobacillus went at the temperature of 37℃in static culture.Through a series of indicators (pH value,absorbance titration acidity,meilan reduction bleaching time and plate counting),the effects of two peptides on the growth and acid production of lactobacillus were compared. The results showed that both soy peptides had great effect of promotion on the growth and acid production of lactobacil- lus,and the best addition of soy peptide in yogurt fermented was 5g/L,.Two peptides compared,the effect of soy peptide B on the growth and acid production of lactobacillus showed more significant.