Effect of xanthan-chitosan-xanthan double layer encapsulation on survival of Bifidobacterium BB01 in simulated gastrointestinal conditions, bile salt solution and yogurt

Xanthan-chitosan hydrogels have been rheologically characterized in the simulated gastrointestinal conditions while the studies on the applicability of the system for anaerobic bacterial Bifidobacterium BB01 encapsulation in yogurt are scarce. The aim of this work was to investigate the effect of a new encapsulation system (xanthan-chitosan-xanthan) on the viability of B. bifidum BB01 in yogurt during 21 days storage at 4 °C and 25 °C, respectively. Chitosan was applied as an inner layer to coat the xanthan-probiotic and xanthan was again used as an outer layer for coating chitosan-xanthan-probiotic particles. Moreover, the probiotic survival under the simulated gastrointestinal conditions and bile salt solution were investigated. The results indicated that xanthan-chitosan-xanthan microcapsules (XCX) and xanthan-chitosan microcapsules (XC) significantly (p < 0.05) improved the cell survival of Bifidobacterium BB01 in yogurt during 21 days storage at 4 °C and 25 °C when compared to free cells. All the microcapsules showed higher cell survival of probiotic in the simulated gastric fluid (SGF) and bile salt solution in comparison to free cells. The XC microcapsules exhibited better release profile than XCX microcapsules in the simulated intestinal fluid (SIF). The results of this study suggested that the new encapsulation systems XCX and XC were effective to improve bacterial survival both during yogurt storage and in the gastrointestinal condition.