Role of Cryoprotectants on the Viability and Functional Properties of Probiotic Lactic Acid Bacteria during Freeze Drying

Effect of different cryoprotectants on acid/bile tolerance, β-galactosidase activity, and cholesterol assimilation properties of freeze dried Pediococcus acidilactici, Lactobacillus plantarum, and Lactobacillus salivarius were evaluated. The retention of probiotic properties and viability of the above three cultures freeze dried with lactose, skimmed milk, and maltodextrin were found to be significant (P ≤ 0.05). In another approach, lactic acid bacteria (LAB) were subjected to cold shock first and then freeze dried. Effect of cold shock treatment on retention of probiotic properties of freeze dried LAB cultures was also investigated. The cold shock treatment resulted in an increase of 6–8%, both in viability and probiotic properties, compared with LAB freeze dried without cold shock treatment. The survival of freeze dried L. plantarum, L. salivarius, and P. acidilactici was investigated over a period of 60 d storage at 4°C. The above three cultures freeze dried with maltodextrin exhibited 83%, 68%, and 60% retention in survival percentage, respectively, in comparison with initial values.