Microencapsulation using two different methods, spray- drying and emulsion technique were applied to preserve the viability of the probiotic Lactobacillus casei during manufacture and refrigerated storage. As coating materials to encapsulate the probiotic by spray-drying method, compatible biopolymers alginate and chitosan were utilized, while as a cross-linking agent, CaCl2 was used. In addition to the probiotic, oligofructose enriched inulin (Synergy 1®) as prebiotic was added to the medium intended for spray-drying. For microencapsulation of the probiotic by emulsion method, alginate and whey proteins were applied. Further, protective effects of four potential cryoprotectants (oligofructose enriched inulin, sorbitol, sucrose, lactose) were investigated when added to the whey proteins-Ca-alginate microparticles before freeze-drying. Experiments showed that chitosan-Ca-alginate microparticles and whey protein-Ca-alginate microparticles with high viability of L. casei were obtained using spray-drying and emulsion method, respectively. Lactobacillus casei encapsulated by emulsion method survived better during 6-months storage at refrigerated conditions than L. casei encapsulated by spraydrying.
Cryoprotectants have no additional effect on the cells survival during freeze-drying, while sorbitol has shown negative impact on the probiotic viability encapsulated in whey protein-alginate and subsequently freeze-dried. No significant differences in viability of L. casei during storage at refrigerated conditions were observed, both in whey proteins-Ca-alginate microparticles as control and formulations containing cryoprotective agent
