Effect of addition of inulin and galactooligosaccharide on the survival of microencapsulated probiotics in alginate beads coated with chitosan in simulated digestive system,yogurt and fruit juice

Galactooligosaccharides (GOS) and inulin were added during microencapsulation of Lactobacillus acidophilus 5 and Lactobacillus casei 01 in alginate beads coated with chitosan at the concentrations of 0, 0.5, 1.0 and 1.5%. Addition of prebiotics significantly (p < 0.05) increased the bead size by approximately 3.8%. The presence of GOS (0.3%) in the microencapsulation provided the best protection with only 3.1 and 2.9 logs reduction for L. acidophilus 5 and L. casei 01, respectively, after incubation in simulated gastric juice (pH 1.55), followed by simulate intestinal juice containing 0.6% bile salt. The viabilities of microencapsulated probiotics containing 1.5% GOS in commercial yogurt and orange juice were also performed at refrigerated storage for 4 weeks. In yogurt, the numbers of cells with GOS were higher than those of without GOS by approximately 1.1 and 0.4 logs for L. acidophilus 5 and L. casei 01, respectively. In orange juice, the numbers of cells with GOS were higher than those of without GOS by approximately 0.5 and 0.4 logs for L. acidophilus 5 and L. casei 01, respectively. The numbers of probiotic bacteria were maintained above the recommended therapeutic minimum (10⁷ cfu g⁻¹ or mL⁻¹ of product) throughout the storage in both products.