Emulsion stability enhancement against storage and environment stresses using complex plant protein and betanin

Complex plant protein has been proved to be a novel protein with high solubility and comprehensive amino acids. The ability to form and stabilize oil-in-water emulsions of rice protein-pea protein and rice protein-soy protein isolate (RP-PP and RP-SPI) prepared through pH-driven method was investigated. Complex plant protein emulsions, especially RP-SPI emulsion, showed better performance on storage stability and environment stress stability than the single plant protein emulsion. According to laser confocal microscopy and particle size analysis, single protein emulsions aggregated rapidly in a short time, and the particle size increased significantly, while the complex plant protein emulsion maintained good dispersibility within 42 days, and the particle size remained around 570 nm. Furthermore, the bioactive natural pigment betanin was added to explore its effect on the stability of the RP-SPI emulsion. The addition of betanin caused a significant reduction in the surface hydrophobicity of RP-SPI and a promotion in the adsorption of protein on the oil-water interface. Betanin have a tendency to enhance the stability of the emulsion with pleasant red color. This study may provide a promising way to develop functional plant-based food emulsion.