Development and characterization of pickering emulsion stabilized by zein/corn fiber gum (CFG) complex colloidal particles

Abstract

Pickering emulsions stabilized by food-compatible particles have drawn researchers’ attention in recent years. In this study, we have fabricated Pickering emulsions stabilized by zein/corn fiber gum (CFG) complex particles (ZCPs) via electrostatic interaction. The particle size of zein nanoparticle was 173.4 ± 2.16 nm, and the ζ-potential was +27.4 ± 1.27 mV. The presence of CFG significantly changed the particle size and ζ-potential of zein nanoparticles. The average ζ-potential of ZCPs was about −27 mV. The average particle size of ZCPs was much larger than that of pure zein nanoparticles, varying from 309 nm to 901 nm. When the mass ratio of zein to CFG was 2:1, ZCPs had the smallest particle size of 309.4 ± 2.48 nm and the ζ-potential was −26.7 ± 0.84 mV, which confirmed the adsorption of CFG onto the surface of zein particles. With an increase in CFG concentration, the contact angles (θo/w) of ZCPs tended to decrease. When the mass ratio of zein to CFG was 2:1, the θo/w was close to 90°, which favored for fabricating stable Pickering emulsion. In addition, at a constant particle concentration, with increasing oil volume fraction, the particle size and viscosity of Pickering emulsion stabilized by ZCPs increased. CLSM and Cryo-SEM observations indicated that ZCPs adsorbed homogeneously at the oil-water interface, and the adsorption of the ZCPs favored the formation of a densely packed layer at the interface, contributing to the formation of gel network structure of emulsion droplets. This study provided new insight into the fabrication food-grade Pickering emulsion, which can be used as delivery system for bioactive compound in food formulations.