Pickering-stabilized emulsion gels fabricated from wheat protein nanoparticles: Effect of pH, NaCl and oil content

A novel Pickering-stabilized emulsion gel with controlled rheological properties was derived from wheat gliadin nanoparticles-stabilized emulsions by altering preparation conditions (pH, ionic strength or oil content). The formed nanoparticles were relatively small uniform spheres particles (d < 120 nm), whose surface potential (ζ-potential) changed from +9.9 mV to −14.19 mV with the pH of the solution increased from 3.5 to 9. The isoelectric point of gliadin nanoparticles was around pH 6.8. The nanoparticles were highly susceptible to aggregation at pH values near their isoelectric point due to a reduction of electrostatic repulsion between them. Pickering-stabilized emulsions could be formed by blending the nanoparticles with oil and water, and Pickering-stabilized emulsion gels were obtained by altering pH, ionic strength or oil content of the dispersions. Creaming stabilities and rheological properties of the emulsion gels were modulated. Stable Pickering-stabilized emulsion gels with relatively large elastic modulus were formed with 70% oil content at pH 5.5 and 6.0 in the absence of NaCl. The viscosity increased with the increasing of oil content and salt concentration, and the viscosity enhanced when the pH around the isoelectric point. These results may facilitate the design of novel viscoelastic emulsion gels with the Pickering-stabilize mechanism which are suitable for utilizing in foods and other products.