Abstract:Rice glutelin (RG) is a commonly used food emulsifier. However, RG easily aggregates into large hydrophobic particles at neutral pH, resulting in poor stability and weak interfacial activity. In this work, RG was modified by pectin through electrostatic complexation, and the effects of the RG-to-pectin ratio on the particle size, contact angle, interfacial adsorption property, and interfacial film structure were investigated. On this basis, these composite particles were utilized as interface stabilizers to fabricate Pickering emulsions, and their particle size distribution, microstructures, rheological properties, and storage stabilities were investigated. The results revealed that when the mass ratio of RG to pectin was 1:1, the average particle size of the composite particles was 675.4 nm and the contact angle is 64.23°. In the meantime, the oil-water interfacial tension was reduced from 36.55 mN/m to 13.00 mN/m, and the interfacial film was mostly elastic, with an elastic modulus of 46.07 mN/m. The Pickering emulsion stabilized by this composite particle had the smallest particle size (d4,3~31.1 μm) and the highest apparent viscosity and storage modulus. Therefore, complexation with pectin can significantly reduce the size of RG and enhance its surface hydrophilicity, thereby improving its abilities to reduce interfacial tension and increase the viscoelastic properties of the interfacial film. These properties are conducive for preparing stable Pickering emulsions. Thus, this study provides a new strategy for expanding the application of RG in food emulsion systems.
