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

Four batches of set yoghurts were made with yoghurt culture Streptococcus thermophilus DD134 incorporating probiotic bacteria (Lactobacillus acidophilus CSCC 2401 and Bifidobacterium infantis CSCC1912) in different states: free, freshly encapsulated, encapsulated and freeze-dried as well as co-encapsulated and freeze-dried. Survival of the probiotic bacteria was monitored over a period of 8 weeks of storage at 5 degree C. The results showed that encapsulation followed by freeze-drying of the probiotic bacterial cells ensured the smallest reduction in the viability of cells in yoghurt. Co-encapsulation of both L. acidophilus 2401 and B. infantis 1912 did not increase viability compared to individual encapsulation of these probiotic bacteria. This study showed that encapsulation improves the viability of probiotic bacteria in yoghurt and therefore makes it a better probiotic carrier food.