Survival of probiotics in pea protein-alginate microcapsules with or without chitosan coating during storage and in a simulated gastrointestinal environment

Pea protein-alginate microcapsules with or without a chitosan coating and containing Lactobacillus rhamnosus R0011 and L. helveticus R0052 were produced by extrusion and tested for survivability during storage and in an in vitro gastrointestinal environment. Both microcapsule formulations provided significant protection for cells incubated in synthetic stomach juice at 37°C for 2 h, followed by 3 h in simulated intestinal fluid, relative to non-encapsulated bacteria. However, evaluation of cell viability during 9 weeks of storage at room temperature revealed that chitosan coating significantly improved microcapsule performance compared to non-coated microcapsules. Refrigerated storage had no negative impact on the microcapsule protection ability of both types of microcapsules. Notably, chitosan-containing microcapsules showed much higher bacterial survival counts during challenge tests even after storage. Moreover, the addition of chitosan to the microcapsule formulation did not increase the microcapsule size.