Effect of Five Materials Including Sucrose, Lactose, Skim Milk, Yeast, Vitamin B2 on Survival of Lactobacillus bulgaricus during Freeze-Drying

Abstract

effect of five materials including sucrose, lactose, skim milk, yeast, vitamin B2on survival rate ofLactobacillus bulgaricusduring freeze-drying was studied by measured survival and the number of viable cells. Designed different concentrations of these different protective agents, respectively, freeze-drying perfectly and then counted the survival ratio ofLactobacillus bulgaricusand the number of viable cells. Results were as follows: addition of skim milk and yeast had significant effects while addition of vitamin B2had minimal impact on survival rate ofLactobacillus bulgaricus. The optimum concentration of single protective agent ofLactobacillus bulgaricusduring freeze-drying was that 25% (W/V) sucrose, 20% (W/V) lactose, 25% (W/V) skim milk, 20% (W/V) yeast and 25% (W/V) vitamin B2, respectively, and survival rate was 24.5%, 35.6%, 64.4%, 62.2%, and 16.3%.