Effect of co-encapsulation of probiotics with prebiotics on increasing the viability of encapsulated bacteria under in vitro acidic and bile salt conditions and in yogurt

Three different complementary prebiotics (selected by in vitro fermentation) were separately co-encapsulated with Lactobacillus acidophilus CSCC 2400 or CSCC 2409 and tested for their efficacy in improving the viability of bacteria under in vitro acidic conditions. Addition of Hi-maize™ starch to capsules containing Lactobacillus spp. provided maximum protection to the encapsulated bacteria after 3 h of incubation at pH 2.0 compared with other 2 prebiotics, Raftiline® and Raftilose®. Viable counts of Lactobacillus spp. increased significantly (P < 0.05) with Hi-maize concentration of up to 1.0% (w/v). Further increase in Hi-maize concentration did not protect the encapsulated bacteria effectively. Effects of 3 different polymers (chitosan, poly-L-lysine, and alginate) were also tested for their efficacy in protecting the encapsulated bacteria at pH 2.0. Addition of Hi-maize (1.0% w/v) to capsules containing Lactobacillus spp. and further coating with chitosan significantly increased (P< 0.05) the survival of encapsulated bacteria under in vitro acidic and bile salt conditions and also in stored yogurt compared with alginate encapsulated cells.