Development and characterization of alginate microcapsules containing Bifidobacterium BB-12 produced by emulsification/internal gelation followed by freeze drying

• Internal ionic gelation provides protection of probiotic cells.
• Encapsulation with freeze drying influenced the survival of the microorganism in storage.
• Encapsulation provides protection of probiotics in gastrointestinal stress tests.

Emulsification/internal gelation is an encapsulation method showing great potential to confer protection on probiotics that need to be added to foods with an unfavorable environment for their viability. The objective of this study was to produce probiotic microcapsules by internal ionic gelation associated with freeze drying, and evaluate the viability of the probiotics under simulated gastrointestinal conditions and their stability during storage. The results showed that microencapsulation culminated in a elevated viability of the probiotics and that the microcapsules were resistant to the simulated gastrointestinal conditions, providing substantial protection to Bifidobacterium BB-12. The encapsulated microorganisms maintained their viability of 7.88 ± 0.05 log CFU g−1 for up to 60 days at 25 °C, but the best results were conserved when submitted to refrigerated (7 °C) or frozen (−18 °C) storage. In addition to the microcapsules remained protected in a solution buffered at pH 4.5 but exposed total release of the probiotics in a solution buffered at pH 7.5, demonstrating conditions of controlled release for use with probiotic carriers for human consumption. Thus, the study demonstrated that emulsification/internal ionic gelation associated with the freeze drying process could be considered feasible technology for the protection, application and controlled release of probiotics for use in foods.