The Fermentation And Storage Properties Of Probiotics In The Yogurt

Lactobacillus casei IMAU20083and Bifidobacterium lactis IMAU60056were isolated from traditional fermented milk and Mongolian healthy children’s gut. The two strains have strong tolerance against the bacteria and bile acid salt, they also have antibiotic property,antioxidase,and immunocompetence. They are the ideal bacteria strains for lactobacillus researching and the development of the probiotic bacteria.This experiment used the commercial yogurt starter YC-X11for longitudinal controlson. Blends Lactobacillus casei IMAU20083and Bifidobacterium lactis IMAU60056(inoculation amount are5×106cfu/g) with YC-X11to make probiotic yogurt. Make a small formula weight for laboratory, and a middle formula weight for factory. Taked the transverse comparison at the same time. Studied the physical and chemical and microbiological properties of the probiotic yogurt in fermentating and storing period, take the sensory characteristics of evaluation at the same time. The purpose is to get the two strains of probiotics’some basic data in fermentation characteristics, in order to provide basis for application development.The results show that, When the fermentation ended, the acidity of the control group (68.8±1.61°T)and the experimental group(70.9±1.81°T,71.3±1.76°T)had no significant difference(P>0.05). The living bacterium number of L. delbrueckii subsp. bulgaricus and5. thermophilus had no significant difference (P>0.05). In4℃and20℃storage21days period, the difference of yoghurt on pH value, titratable acidity (TA), viscosity, syneresis between the control group and the experimental group was not significant (P>0.05) Probiotic Lactobacillus casei IMAU20083and Bifidobacterium lactis IMAU60056counts have a slow growth; At the end of storage time, the counts are7.59(logcfu/ml) and7.82(logcfu/ml). The number of mildew and yeast in the control group significantly lower than the control group (P<0.05); The difference of yoghurt sense perception between the control group and the experimental group was not significant (P>0.05)The results of this study indicates that blending Lactobacillus casei IMAU20083and Bifidobacterium lactis IMAU60056with YC-X11to make probiotic yogurt, will not affect yoghurt viscosity, syneresis, sense perception, etc. And two strains of probiotics both have good storage stability and they can effectually resist the mildew and yeast content, help to raise the overall quality of the yoghurt products.