Development and characterization of high internal phase pickering emulsions stabilized by heat-induced electrostatic complexes particles: Growth nucleation mechanism and interface architecture

Abstract

In this work, the heat-induced ovalbumin (OVA)-pectin (PE) electrostatic complex particles (HIECP) prepared by different heating sequences (type I particles (I): Heat-treated ovalbumin/pectin complexes at pH 4; type II particles (II): Complexes between pre-heated ovalbumin and pectin at pH 4) and biopolymer ratios were used as stabilizers to form high internal phase Pickering emulsions (HIPPEs). The results showed that I had a more compact structure, higher net surface charge, and smaller particle size than II, due to the different growth nucleation mechanism. II-stabilized HIPPEs exhibited a smaller oil droplet size, stronger gel structure, and better stability than I-stabilized HIPPEs, owing to their suitable wettability, rigid "core-shell" structure, and robust and dense interface architecture. Moreover, the stability and gel-like structure of HIECP-stabilized HIPPEs improved with increasing PE content due to steric barrier and thickening effects. Our findings provide a new perspective for understanding heat-induced biopolymer particles as effective Pickering stabilizers.

Keywords: Growth nucleation mechanism; Heat-induced electrostatic complexes particles; High internal phase Pickering emulsion; Self-assembly; Stability.