Microencapsulation of Lactobacillus casei with calcium alginate-resistant starch and evaluation of survival and sensory properties in cream-filled cake

Lactobacillus casei ATCC 39392 was encapsulated with calcium alginate-resistant starch via emulsion technique. The probiotics bacteria were inoculated to cream-filled cake in their free and microencapsulated forms. The survival of free and microencapsulated bacteria and pH changes in cream-filled cake were monitored during 4 weeks storage at 4 and 25 degrees C. The morphology and size of microcapsules were measured by optical microscopy, scanning electron microscopy (SEM) technique and particle size analyzer. The results showed that the pH changes of cream-filled cake with microencapsulated L. casei were slower than product containing free L. casei during storage. The survival rate of microencapsulated L. casei was significantly higher than free bacteria (P < 0.05) due to the protective property of calcium alginate capsules and low temperature (4 degrees C). The inoculation of probiotic culture either in encapsulated or free state had no significant effect on texture, color, flavour, taste and overall sensory characterization of cream filled cake over the storage period at 4 degrees C (P > 0.05). The results also indicated that calcium alginate-resistant starch enhanced the survival rate of probiotic bacteria in the product.