Survival of Bifidobacterium breve in Acidic Solutions and Yogurt, Following Immobilization in Calcium Alginate Beads

Survival of Bifidobacterium breve in Acidic Solutions and Yogurt, Following Immobilization in Calcium Alginate Beads

Sodium alginate was used to immobilize Bifidobacterium breve ATCC 15700 cells. The ability of the Ca-alginate beads to protect the B. breve ATCC 15700 was evaluated under different conditions including alginate concentration, bead size, pH, hydrogen peroxide, and storage period. The survival of the B. Breve ATCC 15700 was estimated in pasteurized yogurt, containing either the immobilized or free cells, throughout the storage period. The survival cells in bead after exposure to acidic solution (pH 3.0) increased with increase of both the alginate gel concentration and bead size. Also, immobilized cells in alginate bead were more resistant than the free cells to hydrogen peroxide, storage period, and the environment inside yogur. When retreated beads with skim milk and nonretreated beads were tested in acidified pH 3.0 TPY media including acetic and lactic acid, the number of viable cells in the retreated bead was approximately 10-fold higher than that of nonretreated beads. This suggests that the skim milk operated as a material decreasing the diffusion of acid and hydrogen perosicde into alginate gels. From this research, it was found that yogurt itself supported immobilized cells with an improved protection from the extreme acidity in yogurt.