Study on the effect of Bifidobacteria on fermented milk quality
Bifidobacterium is widely added to fermented milk as probiotics,but its influence on the quality of fermented milk is less studied.In this study,the synergistic effect of three kinds of Bifidobacterium,namely Bifidobacterium animalis(Ba)i797,Bifidobacterium bifidum(Ba)i771 and Bifidobac-terium longum subsp.longum(Ba)i772,with two kinds of starter cultures and their effects on the quality of fermented milk were evaluated.The re-sults showed that the fermentation speed of all fermented milk with Bifidobacterium increased,and the number of viable Lactobacillus bulgaricus in-creased at different levels after fermentation.The viscosity,exopolysaccharides(EPS)content,β-galactosidase activity,DPPH radical scavenging rate,hydroxyl radical scavenging rate and superoxide anion radical scavenging rate increased significantly(P＜0.05),and the particle size decreased significantly(P＜0.05).In addition to the above characteristics,the measurement index of fermented milk added with Ba i797 was the best.Com-pared with the first day,the number of viable bacteria decreased,the viscosity,EPS and antioxidant activity increased significantly(P＜0.05),and the water holding capacity,particle size,stability and β-galactosidase activity decreased significantly(P＜0.05).The addition of Bifidobacterium would up-set the balance of original fermentation strains,and the interaction between Lactobacillus bulgaricus and Streptococcus thermophilus could improve the quality of fermented milk,and enhance the probiotic characteristics,but its interaction mechanism needed further study.
fermented milkBifidobacteriaqualityimproving effectphysical and chemical characteristicsprobiotic characteristics
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