PromotingLactobacillus caseiandBifidobacterium adolescentissurvival by microencapsulation with different starches and chitosan and poly L-lysine coatings in ice cream

In this research, microencapsulation of the probiotics Lactobacillus casei ATCC 39392 and Bifidobacterium adolescentis ATCC 15703 was performed using calcium alginate, wheat, rice, and high-amylose corn (Hylon VII) starches along with chitosan and poly L-lysine coatings. The effect of microencapsulation on the survival and sensory properties of ice cream over 100 days at −30 °C was evaluated. Scanning electron and optical microscopy were employed to measure capsule size and morphology. The results suggested that the survival of probiotics is increased by microencapsulation. Coating the capsules with chitosan and poly L-lysine led to enhanced bacterial viability and an increase in the size of microcapsules. Among different starches, Hylon starch enhanced the survival of probiotics at low temperatures the most. Furthermore, the addition of probiotics in free and encapsulated states did not have a significant effect on the sensory properties, or pH levels of the final product during storage (p > .05). Practical applications Microencapsulation using various hydrocolloids is a commonly used method for enhancing probiotic survival in ice cream during the frozen storage. This study indicates that the microencapsulation of probiotics can enhance probiotic survival in ice cream after 100 days of storage at −30 °C. Chitosan and poly L-lysine coatings significantly improved the survival of encapsulated probiotics during the storage of ice cream. This improvement is attributed to the role of Hylon starch in creating more integrated microcapsule structure. Moreover, sensory evaluation of ice cream revealed that inoculation with the probiotic culture, in either the encapsulated or the free-state, had no significant effect on texture, color, flavor, taste, or general sensory characterization of ice cream during the storage period at −30 °C (p > .05).