Encapsulation in alginate-coated gelatin microspheres improves survival of the probiotic Bifidobacterium adolescentis 15703T during exposure to simulated gastro-intestinal conditions

Alginate-coated gelatin microspheres were produced to encapsulate the probiotic Bifidobacterium adolescentis 15703T with the objective of enhancing survival during exposure to the adverse conditions of the gastro-intestinal tract. Gelatin microspheres were cross-linked with the non-cytotoxic genipin and coated with alginate cross-linked by Ca2+ from external or internal sources.

The alginate coat prevented pepsin-induced degradation of the gelatin microspheres in simulated gastric juice (pH 2.0, 2h), resulting in significantly (P<0.05) higher numbers of survivors due to the buffering effect of intact microspheres. After sequential incubation in simulated gastric (1h) and intestinal juices (pH 7.4, 4h), number of surviving cells were 7.6 and 7.4logcfuml−1 for alginate coated microspheres by the internal and external Ca2+-source methods, respectively, while 6.7 and 6.4logcfuml−1 were obtained for cells in uncoated gelatin microspheres and free cells, respectively.

This study presents a novel microencapsulation method, which protects probiotic bifidobacteria during exposure to adverse environmental conditions.