Effects of different dispersion methods on the pre-emulsification oil of loaded polyphenol

Recently, chemical or physical modification to improve the emulsification stability of proteins has received extensive attention. Surimi products may benefit from pre-emulsified oils with added antioxidants. Therefore, we explored how different pre-emulsification methods affect the characteristics of pre-emulsified oil loaded with antioxidants, aiming to optimize the pre-emulsified product and, thus, improve the quality of surimi products. We tested high-speed homogenization (HSH), ultrasonic emulsification (UE), and high-pressure microfluidization (HPM) treatments. Purified water was mixed with peanut oil, 2% soy protein isolate, and 0.15% of epicatechin (EC) or epigallocatechin gallate (EGCG) (polyphenols), and a stable pre-emulsified oil system was formed by HSH, UE, or HPM. The emulsifying activity and stability of the polyphenol-loaded peanut oil pre-emulsion was the highest with the HPM treatment, followed by UE. The HPM treatment significantly increased the emulsion viscosity, decreased the droplet particle size, and increased the amount of protein adsorption on the surface of the droplet compared with the UE and HSH treatments, enhancing the emulsification effect. In addition, the emulsion with EGCG has stronger oxidation resistance and smaller particle size than that of EC emulsion. Thus, the HPM treatment with EGCG is an effective means to increase the emulsification and stability of the pre-emulsion. • Surimi products may benefit from pre-emulsified oils with added antioxidants. • HPM was the best dispersion method, followed by UE. • HPM resulted in small particle size and increased protein adsorption and viscosity. • Better inoxidizability and particle size was in emulsions with EGCG than with EC. • Emulsion treated with HPM and EGCG increased its stability.