Survival of microencapsulated Lactobacillus casei ATTC 393 under simulated gastrointestinal condition

Nowadays there is an upsurge of interest in developing novel foods containing probiotic microorganisms, such as bifidobacteria and lactic acid bacteria (LAB). Such functional foods demonstrate a great potential in promoting human health. Maintenance of the intestinal microbial homeostasis, prevention of pathogenic infections, stabilization of the gastrointestinal barrier function, reduction of blood cholesterol and production of anti-carcinogenic and anti-mutagenic compounds are included among the beneficial effects of probiotic-based foods. However, in order to exert these beneficial effects to the host, probiotics must survive transit through the gastric environment and reach the colon in large quantities to facilitate colonization. Unluckily most of the probiotics, including LAB, lack the ability to survive in a high proportion the harsh acidic environment of the stomach and the bile salts secreted into the duodenum. The delivery of active probiotic cells in microencapsulated form has received reasonable attention during the last ten years, in order to increase the survival of probiotics to such conditions. In the present study microencapsulated cells of Lactobacillus casei ATCC 393 were prepared by spray drying (with skimmed milk), extrusion (calcium alginate beads) and emulsion (casein-based microencapsulation) techniques. Survival of these microencapsulated and free cells of L casei ATCC 393 in simulated gastric juice (pH 2.0 and pH 3.0) and bile solution was investigated. Microencapsulated L. casei ATCC 393 exhibited a lower population reduction than the free cells during exposure to simulated gastric environment and bile solution. This phenomenon was most pronounced when L. casei ATCC 393 was exposed to pH 2.0 and high concentration of bile solution. Moreover, it was also observed that the protective effect exerted by microencapsulation varied with the technique used. Finally, results indicated that all microencapsulation techniques used in the present study could successfully protect L. casei ATCC 393 against adverse conditions and this approach might he useful in the delivery of probiotic cultures as a functional food.