Pickering emulsions stabilized by β-Lactoglobulin-Rosmarinic acid-Pectin nanoparticles: Influence of interfacial behavior and rheology performance

Grafting polyphenols and glycosylation are effective means to enhance the wettability and emulsifying properties of natural protein particles. A stable pickering emulsion (PE) with antioxidant properties was prepared using β-Lactoglobulin-Rosmarinic acid-Pectin (β-LG-RA-PC) conjugates as stabilizers in this study. When PC and β-LG-RA with the same mass were covalently combined, the solid protein-based particles exhibited ideal wettability (84.2 ± 0.3°), emulsification performance, and molecular flexibility. PEs with an oil content of 66.7% were successfully prepared using a 10 mg/mL concentration of the complex. The intrinsic reasons for the stabilization of the PE were explored through interfacial tension (from 16.02 mN/m to 12.18 mN/m), adsorption kinetics, interfacial expansion viscoelastic modulus (the tangent of the phase angle was 0.22), microstructure, and rheological properties, revealing that the dense, ideally viscoelastic interface layer formed was the main factor. The electrostatic repulsion between droplets, and the formation of a robust spatial network structure, facilitated PEs' stability. These studies confirmed the possibility of implementing protein-based particles to yield food-grade PE.