The formation and characterization of antioxidant pickering emulsions: Effect of the interactions between gliadin and chitosan

Abstract

This paper investigated the formation of Pickering emulsion stabilized by three types of structure of gliadin–chitosan nanoparticles (GCNPs). The stability, rheological and antioxidant properties of the Pickering emulsion were mainly studied. Three types of GCNPs structure, including primary complexation, soluble complexes, and coacervates were obtained by a facile pH alteration approach to represent three kinds of gliadin–chitosan interaction levels. The obtained GCNPs with diverse size (125.13–5000.67 nm) and various wettability (θ = 37.88–96.32°) were then selected to fabricate Pickering emulsion. The droplet size of Pickering emulsions stabilized by soluble complexes and coacervates showed unimodal distribution with high symmetry. The surface loading and microstructure of emulsion confirmed that the coacervates could stabilize more oil (90.24%) via bridging droplets together and producing the percolating network structure against coalescence. The coacervate-stabilized Pickering emulsions were especially stable during the storage period, showing high viscoelasticity and solid-like behavior. Furthermore, the retarding effect of Pickering emulsion by embedding curcumin was confirmed and the coacervates were resistant to lipid oxidation, evidenced by low lipid hydroperoxides (15.22 mmol/kg of oil) and hexanal levels (Peak area 73.9) in the emulsions after thermally-accelerated storage. The findings showed that the stability, rheological and antioxidant properties of GCNPs stabilized Pickering emulsion could be regulated by gliadin–chitosan interactions through only changing pH. This study could be an available reference for the practical applications of Pickering emulsions stabilized using the gliadin–chitosan systems.