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Aim of this work was the development of integrated and complex encapsulating systems that will provide more efficient protection to the probiotic strain Bifidobacterium animalis subsp. lactis (BB-12) in comparison to the conventional plain alginate beads. Within the scope of this study, the encapsulation of BB-12 through emulsification followed by external gelation was performed. For this purpose, a variety of alginate-based blends, composed of conventional and novel materials, were used. The results demonstrated that alginate beads incorporating 1% carrageenan or 2% nanocrystalline cellulose provided great protection to the viability of the probiotic bacteria during refrigerated storage (survival rates of 50.3% and 51.1%, respectively), as well as in vitro simulation of the gastrointestinal tract (survival rates of 38.7 and 42.0%, respectively). The incorporation of glycerol into the formulation of the beads improved the protective efficiency of the beads to the BB-12 cells during frozen storage, increasing significantly their viability compared to the plain alginate beads. Beads made of milk, alginate 1%, glucose 5%, and inulin 2% provided the best results in all cases. The microstructure of beads was assessed through SEM analysis and showed absence of free bacteria on the surface of the produced beads. Consequently, the encapsulation of BB-12 through emulsification in a complex encapsulating system was proved successful and effective.

Due to the shift towards healthy lifestyles, the food industry focuses on expanding the production of probiotic food products. Τhe incorporation of probiotic bacteria into the food matrix is challenging because various processes can damage cells’ viability. In this study, an innovative and advanced encapsulation approach combining the extrusion technique with the technique of double emulsification (W1/O/W2 emulsion system) is proposed for the protection of Bifidobacterium lactis (BB-12). Different W1/O/W2 emulsion formulations were investigated using various encapsulating agents as wall materials for satisfactory encapsulation of BB-12 cells. The probiotic cells were incorporated in the double emulsion prior to extrusion and their viability was evaluated by exposing them to different storage temperatures and various pH values, as well as to simulated gastrointestinal fluids. The results demonstrated that the viability of probiotics, when using the proposed encapsulation system, maintained above 6 log cfu g−1 during storage at 4 °C and −18 °C for 4 weeks, while the BB-12 cells encapsulated through conventional extrusion were decreased significantly (survival rate 46.8%) after 15 days of storage. Moreover, this novel system provides high survival rates during the in vitro simulation of the gastrointestinal system (up to 86.1%) and at various pH environments (up to 98.5%).