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 (W 1 /O/W 2 ) 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 10 7  CFU/mL at 6 h. The lyophilized ACG-3 hydrogel beads exhibited the viable release amount of 8.4 × 10 7  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.