Functional properties of free and encapsulated Lactobacillus reuteri DPC16 during and after passage through a simulated gastrointestinal tract.

Lactobacillus reuteri DPC16 is a probiotic bacterium that has strong antimicrobial activities on pathogens, mainly due to its ability to produce reuterin, an antimicrobial compound. The objective of this study was to examine the ability of an encapsulation technique to protect the functional properties of cells of L. reuteri DPC16 during passage through a simulated GI tract. The functional properties of the cells were studied before and after passage through the tract. An alginate-skim milk encapsulation system was used to deliver the probiotic bacterium through the simulated GI tract, allowing for the release of the cells into the simulated colonic fluid. The cells were then isolated and cultured. The recovered cells showed no diminution in functional properties, including their growth kinetics, ability to adhere to epithelial cells and ability to inhibit the adhesion of E. coli to epithelial cells. The bacteriostatic and bactericidal properties of the recovered cells against some pathogens were significantly greater (P < 0.05) than those of the original cells. Production of reuterin by the recovered cells was significantly greater than that of the original cells when cultured in MRS medium in the absence of its metabolic precursor, glycerol. The results demonstrate significant consequences for the application of the encapsulation technique to protect and/or enhance the functional properties of the probiotic cells.