Use of encapsulated Bifidobacterium animalis subsp. lactis through extrusion or emulsification for the production of probiotic yogurt

In this study, the methods of extrusion and emulsification were applied for the encapsulation of Bifidobacterium animalis subsp. Lactis before its incorporation into yogurt products, aiming to increase its viability during storage. Alginate based encapsulating blends containing 2% w/v sodium alginate and 11% v/v glycerol (AG) or 1% carrageenan (AC), and/or 2% w/v inulin, were applied for the encapsulation of probiotic bacteria. The produced beads were examined in order to determine the encapsulation yield and were also tested on milk fermentation along with conventional starter culture for yogurt production. The evolution of the fermentation was recorded through pH monitoring and the final products were evaluated regarding their rheological and texture characteristics, as well as their probiotic bacterial load during storage. It was concluded that the emulsification method led to higher encapsulation yield (95.4–97.6%) compared to the extrusion method (76.6–85.8%). The probiotic culture contributed to milk fermentation into yogurt, as it required less time to complete fermentation compared to samples containing only conventional culture. The encapsulation of probiotic bacteria was proved efficient in protecting their viability even after 30 days of storage (up to 6.9 log cfu/g). Thus, the incorporation of encapsulated probiotic bacteria improved in total the yogurt products and ensured the viability of probiotic bacteria till the end of storage. Practical Applications The encapsulation of probiotic bacteria is an innovative approach for their protection and the ensuring of their viability during food processing and storage, as well as during consumption. The methods of extrusion and emulsification are feasible and affordable in industrial scale. The current study provides an integrated approach of their application in yogurt production, without restricting the utilization of the produced encapsulated bacteria for the development of other probiotic products. The incorporation of encapsulated probiotic bacteria along with the conventional culture led to shorter fermentation times, and superior final products in comparison to conventional yogurt products. The final products had improved rheological and texture characteristics, whereas the viability of the probiotic bacteria remained at satisfactory levels till the end of storage.