Viability and survival of free, encapsulated and co-encapsulated probiotic bacteria in ice cream

Four batches of ice cream were made incorporating probiotic bacterial cultures (Lactobacillus acidophilus 2401 and Bifidobacterium infantis 1912) in different states: free, freshly encapsulated, encapsulated and freeze-dried and co-encapsulated and freeze-dried. Survival of the probiotic bacteria was monitored over a period of 24 weeks of storage of the ice creams at -20degreesC. The results showed that free cells survive better (approximately 1 log difference) than freshly encapsulated cells in ice cream. Co-encapsulation of L. acidophilus 2401 and B. infantis 1912 enhanced survival of both strains as compared with individual encapsulation of the same strains. Freshly encapsulated cells showed greater survival than those that were freeze dried after encapsulation, this is advantageous in terms of ice cream production because, less processing of the cells is required before incorporating into the ice cream mix. Addition of encapsulated cultures did not show any effect on the amount of air incorporated into the ice cream.