Protection of PVP K-30 to freeze-dried Lactobacillus acidophilus
Polyvinyl Pyrrolidone K-30,abbreviated to PVP K-30,as a new safety food additive,is extensively used in food domain.Taking the survival rate of Lactobacillus acidophilus as measure,research on freeze-dried protective capability of PVP K-30,comparing with other 12 types of common used cryoprotectants,four cryoprotectants were gotten to compound with PVP K-30,L16(45)orthogonal test of five cryoprotectants were performed.The result shows that the protecting effect of composite cryoprotectants was obviously better than that of single cryoprotectant;PVP K-30 can markedly enhance protection capacities of skim milk and trehalose.The optimum formula of the cryoprotectant was determined as:PVP K-30 4%,skim milk 20%,trehalose 6%,sodium glutamate 0.5%,glycerol 4%,protecting Lactobacillus acidophilus with the survival rate up to 93.33%.