Incorporation of polysaccharides into sodium caseinate-low melting point fat microparticles improves probiotic bacterial survival during simulated gastrointestinal digestion and storage

In our previous study we reported that sodium caseinate (NaCas) can effectively protect probiotic bacterial cells from heat inactivation during spray drying in the presence of low melting point fat (LMF). The objective of the current research was to enhance the gastric resistance and storage properties of NaCas-LMF based probiotic microparticles by incorporating different carbohydrate polymers. Probiotic bacteria were spray dried in NaCas solutions containing LMF combined with one of: maltodextrin, pullulan, gum ghatti or gum arabic (GA). Probiotic bacteria only showed good survival (>= 50%) after spray drying in microcapsules formulated with gum ghatti or gum arabic. Addition of GA and gum ghatti to NaCas showed a positive effect on the in vitro gastric resistance of probiotic bacteria, whereas maltodextrin and pullulan exerted a negative influence. Among the formulations tested, microparticles made from a blend of NaCas and GA showed the highest glass transition temperature (T-g), corresponding to the best survival of probiotic bacteria during storage for up to 16 weeks in a water activity range of 0.11-0.76. The presence of two T(g)s in the NaCas-pullulan matrix suggested that phase separation was occurring, which could partially account for its poor protection capacity. Encapsulated probiotic bacteria in all matrices showed good release properties in the presence of pig intestinal digesta; release from microparticles was complete in less than 1 h. The current study demonstrates that NaCas-LMF combined with GA may provide effective protection to probiotic bacterial cells not only during spray drying, but also during storage and in vitro digestion. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.