Microencapsulation of Bifidobacterium animalis subsp. lactis BB-12 with mannitol

Bifidobacterium animalis subsp. lactis BB-12 (BB-12) was microencapsulated using co-extrusion technology with chitosan coating and the incorporation of mannitol as prebiotic. Optimization of coating material chitosan concentration (0–0.5% w/v) and mannitol concentration (0–5% w/v) as prebiotic were performed to determine the formulation that produces beads with desired properties. The microencapsulation efficiency (MEE) of free and microencapsulated BB-12 (with and without mannitol) were determined. All forms of BB-12 further subjected to sequential digestion in simulated gastric juice (SGJ, pH 2.0) for 2 hours and simulated intestinal juice (SIJ, pH 7.5) for 3 hours. The results indicated that 0.4% (w/v) of chitosan coating and 3% (w/v) of mannitol were the optimum concentrations to produce microencapsulated BB-12 with the highest MEE of 89.15% and the average bead size of 805 µm. The BB-12 beads produced through co-extrusion were spherical with a smooth surface. Throughout the five hours sequential gastrointestinal digestion, both microencapsulated BB-12 with and without mannitol were able to maintain their viable cell count at least 106 CFU/g at the end of the incubation. The presence of prebiotic mannitol showed a significant protective effect on the microencapsulated BB-12 during gastrointestinal transit.