Carboxymethyl konjac glucomannan-chitosan complex nanogels stabilized double emulsions incorporated into alginate hydrogel beads for the encapsulation, protection and delivery of probiotics

In this study, we developed (W1/O/W2) double emulsions encapsulated by calcium-alginate hydrogel beads system (ACGs) for intestinal-targeted delivery of probiotics (Lactobacillus reuteri). Firstly, the carboxymethyl konjac glucomannan-chitosan (CMKGM-CS) nanogels were successfully fabricated by EDC/NHS initiated crosslinking, as concluded from the TEM images, FTIR spectra, XRD, etc. Then, double emulsions were prepared and encapsulated with various concentrations of alginate to form ACGs hydrogel beads. In vitro probiotic release experiments showed the lyophilized ACG-2 and ACG-3 hydrogel beads had a sustained release in simulated intestinal fluid (SIF), the viability of cells exceeded 107 CFU/mL at 6 h. The lyophilized ACG-3 hydrogel beads exhibited the viable release amount of 8.4 × 107 CFU/mL after storage for 90 d at 4 °C. Besides, the alginate concentration in the ACGs hydrogel beads influences the swelling behavior and structure of hydrogel beads by affecting the hydrogen bonds between alginate and CMKGM-CS, thereby mediating the release of probiotics.