Interfacial characterization of an oxidative pickering emulsion stabilized by polysaccharides/polyphenol complex nanogels via a multiscale study

Incorporating antioxidants into the soft colloidal emulsifiers has been necessarily required to prepare antioxidant Pickering emulsions. Establishing interfacial properties-physical and chemical properties relationships has not been deeply explored by a comprehensive multiscale approach. Herein, the polysaccharide composite nanoparticles acted as antioxidants interface-anchored reservoirs were designed via non-covalent interaction between hydroxypropyl chitosan (HPCS), sodium alginate (Alg) and purple corn bracts anthocyanins (PCBA) at the molecular level. The orderly packing HPCS-Alg/PCBA composite nanoparticles formed the more highly-dense adsorption layers at oil/water interfaces at the microscopic level. With increasing the PCBA concentration, the bridged network particle aggregates between neighboring droplets resulted in a smaller size at the mesoscopic level and higher bulk stability at the macroscopic level. Interestingly, the bridged structures formed stronger antioxidant shells around dispersed droplets, further improving oxidative stability. These results highlighted the characteristics of the interfacial layers (thickness, strength, and viscoelasticity) that could be engineered to regulate the oxidation stability of Pickering emulsions at different scales. Therefore, this work proposed a novel strategy to protect lipid droplets of emulsions via manipulating the antioxidative soft colloidal particle's interfacial properties in the Pickering emulsions system, further extending the applications of antioxidant Pickering emulsions in food colloidal fields.