Optimization of pH-responsive microgel for the co-delivery of Weizmannia coagulans and procyanidins to enhance survival rate and tolerance

The purpose of this study was to prepare a pH-responsive microgel for co-delivering Weizmannia coagulans 99 (BC99) and procyanidins (PCs) to enhance the survival rate and tolerance of probiotics in complex micro-environment. The effects of different concentrations of PCs on the properties of microgels were optimized, and found that the spherical microgels had higher encapsulation efficiency (90.27 ± 2.51%) and smaller size when the concentration of PCs was 20 μg/mL. The interaction among PCs, pectin and protein could effectively improve the survival rate of BC99 under different pH, bile salt, digestive enzyme and temperature conditions, maintain their stability in acidic gastric fluid, and realize the release of probiotics in neutral intestinal fluid. Moreover, the microgel was able to protect BC99 against H 2 O 2 and antibiotics. This work provides a pH-responsive co-loaded microgels for BC99 and PCs, and has the potential in the loading and delivery of other probiotics and polyphenols.