Abstract:In this study, monodisperse droplet generator (MDDG) was utilized to produce multilayered probiotic microcapsules through using calcium alginate gel (-) (as the matrix), chitosan (+) and gum Arabic (-) (as the coating materials), and adopting a layer-by-layer approach based on electrostatic self-assembly. The results showed that the multilayered probiotic microcapsules had higher mechanical strength, and still maintained intact spherical structure after 9 h of culture in MRS liquid medium, with an increase (by 2.06 log cfu/g) in the number of probiotics contained in the microcapsules. In addition, multilayer structure prolonged the existence time of microcapsules prior to disintegration in the gastrointestinal juice. The single-layered calcium alginate microcapsules collapsed rapidly in the simulated intestinal fluid, with the amount of released probiotics reaching 8.23 log cfu/g after 1 h of digestion. Whereas, the probiotic microcapsules coated with chitosan, chitosan and gum arabic gum did not reach the corresponding logarithmic values (8.42 log cfu/g and 8.33 log cfu/g, respectively) until 3 h after digestion. Compared with the single-layer probiotics microcapsules, the multilayered microcapsules showed a higher storage stability at both 4 ℃ and 25 ℃, with the number of viable cells in the three-layered microcapsules coated with calcium alginate-chitosan-gum arabic decreasing from 8.90 log cfu/g to 8.81 log cfu/g after a storage at 4 ℃ for 12 days. The experimental results showed that MDDG combined with electrostatic-guided layer-by-layer self-assembly was an effective method for efficient preparation of homogeneous and stable probiotic microcapsules to enable the delivery of probiotics into the intestines.
