真空冷冻干燥法制备益生菌粉的冻干保护剂配方优化

为提高益生菌冻干粉存活率。本文采用真空冷冻干燥法，分别以植物乳杆菌SC1、凝结芽孢杆菌XP2、酿酒酵母菌SA1为实验菌株，研究冻干保护剂脱脂乳粉、低聚木糖、可溶性淀粉和V_C钠盐对三种益生菌冻干存活率的影响。通过单因素和正交试验筛选出最优组合。结果表明经-70℃预冷冻2 h，-50℃，10 Pa条件下冷冻干燥38 h，保护剂最佳配方组合分别为，植物乳杆菌:可溶性淀粉10%，V_C钠盐3%，脱脂乳粉12%，低聚木糖14%；凝结芽孢杆菌:低聚木糖8%，V_C钠盐4%，可溶性淀粉14%，脱脂乳粉8%；酿酒酵母菌:低聚木糖10%，V_C钠盐2%，脱脂乳粉12%，可溶性淀粉12%。添加最优保护剂组合，三株菌的冻干存活率分别为83.2%、83.7%和86.7%，活菌数均高于1.0×108 CFU/g，具有较好的应用价值。

Formulation Optimization of Freeze-Drying Protectant for Probiotics Powder by Vacuum Freeze-Drying

In order to improve the survival rate of probiotics lyophilized powder,the effects of freeze-drying protectants on the survival rate of probiotics were studied using vacuum freeze-drying mothod. The protectants included skim milk powder,xylo-oligosaccharides,soluble starch and V_Csodium salt and the probiotics included Lactobacillus plantarum SC1, Bacillus coagulans XP2 and Saccharomyces cerevisiae SA1. The optimum combinations were selected by single factor and orthogonal test. With the pre-freezing temperature -70 ℃,2h,and freezing temperature -50 ℃,10 Pa,38h,the best formula combinations of protectant for L. plantarum was soluble starch 10%,V_Csodium salt 3%,skim milk powder 12%,xylo-oligosaccharide 14%;the best formula combinations of protectant for B. coagulans was xylo-oligosaccharide 8%,V_C sodium salt 4%,soluble starch 14%,skimmed milk powder 8%;the best formula combinations of protectant for S.cerevisiae was xylo-oligosaccharide 10%,V_C sodium salt 2%,skimmed milk powder 12%,soluble starch 12%. Under the optimal formula protectant,the freeze-drying survival rate of the three strains were 83.2%,83.7% and 86.7% respectively,and the number of viable bacteria were all higher than 1.0×108 CFU/g,which has a good commercial application value.