Three protective agents for pectin-rice bran capsules for encapsulating Lactobacillus plantarum

Three protective agents, maltodextrin, wheat dextrin soluble fiber, and hi-maize starch were separately incorporated into pectin-rice bran capsules prepared by ionotropic gelation and loaded with Lactobacillus plantarum. Capsules were then coated with whey protein isolate and freeze dried. Capsules that were not coated were used as controls. The viability of encapsulated cells in the freeze dried capsules was evaluated after freeze drying and at simulated gastrointestinal conditions. The whey protein isolate coating significantly enhanced viability of the encapsulated cells after the freeze drying. The freeze dried capsules with hi-maize starch (FHMC) had the highest cell viability, 8.63±0.01 and 5.63±0.02 log CFU/g for the coated and uncoated capsules, respectively. In simulated gastrointestinal conditions, only 0.89 and 2.12 log cycles were reduced, when the encapsulated cells of FHMC were exposed to fed state with a copious meal (at pH 3.0, followed by pH 7.0) and with a standard meal (at pH 2.5, followed by pH 6.5) condition, respectively. Due to the effect of pH 1.8, low numbers of viable cells were recovered from FHMC (3.27±0.13 log CFU/g) after incubating in a fasted state without meal, while there was no cell survival found in other treatments.