Chitosan/guar gum nanoparticles to stabilize Pickering emulsion for astaxanthin encapsulation

Pickering emulsions stabilized by biopolymers have been gaining increasing attention in recent years. In this work, chitosan/guar gum (CS/GG) nanoparticles were formed by hydrogen bond interactions between amino of CS and hydroxyl of GG. The surface charge and aggregation degree of CS/GG nanoparticles could be regulated by pH value to yield Pickering emulsion of superior quality. Emulsions had optimal physical stability at pH 6.0 and oil fraction of 0.6, with the lowest creaming index of 1.81 +/- 0.21% after six months of storage at 4 ?C. Contents of primary and secondary oxidation products stored at 37 ?C for 30 days in Tween 80-stabilized emulsion are almost 1.46 and 1.66 times that of CS/GG-stabilized Pickering emulsion. These results indicated that CS/GG-stabilized Pickering emulsion had better lipid oxidation stability than Tween 80-stabilized emulsion. In addi-tion, the retention rate of astaxanthin of CS/GG-stabilized astaxanthin Pickering emulsion (85.9 +/- 0.57%) was higher than Tween 80-stabilized astaxanthin emulsion (66.12 +/- 0.71%) stored at 37 ?C for 30 days. This result indicated that the stability of CS/GG-stabilized astaxanthin-loaded Pickering emulsion was better than Tween 80-astaxanthin emulsion. This study provides a framework for applying Pickering emulsions formed using poly-saccharide particles in functional foods.