Fabrication and characterization of oleogels stabilized by metal-phenolic network coatings-decorated zein nanoparticles

Abstract

Self-assembly coatings are used to functionalize the surface structures of protein. Herein, emulsion-templated approach was adopted to obtain oleogels using metal-phenolic network coatings-decorated zein nanoparticles. Two self-assembly strategies were used to decorate zein nanoparticles: 1) adding (-)-epigallocatechin-3-gallate (EGCG) first and then calcium ions (Ca²⁺) (zein/EGCG/Ca²⁺ nanoparticles). 2) adding Ca²⁺ first and then EGCG (zein/Ca²⁺/EGCG nanoparticles). The formation of nanoparticles, the stability of emulsions and the rheological behaviors of oleogels were modulated by using different adding sequences of EGCG and Ca²⁺. Nanoparticles prepared by two self-assembly strategies exhibited increasing diameter (340-360 nm). More Ca²⁺ participated in the formation of zein/EGCG/Ca²⁺ nanoparticles, as described by X-ray photoelectron spectroscopy analysis. Metal-phenolic network coatings facilitated the formation of well-structured emulsions and oleogels, which were candidates for fat substitutes and stable carriers. Findings confirmed metal-phenolic network coatings-decorated zein nanoparticles were effective stabilizers for emulsions and oleogels, further expanding the selectivity of oleogelators.

Keywords: (-)-epigallocatechin-3-gallate; Calcium ions; Metal-phenolic network coatings; Oleogels; Rheological behaviors; Zein.