Relationship between protein native conformation and ultrasound efficiency: For improving the physicochemical stability of water–in–oil emulsions

To reveal the relationship between the native conformation of proteins and ultrasound efficiency, the effects of ultrasound power (0–500 W) on the structures and properties of different types of proteins (sodium caseinate, CAS; whey protein isolate, WPI; chickpea protein isolation, CPI; and pea protein isolation, PPI) were investigated. The results showed that the extent of structural changes of proteins depended on their native conformation rather than their origin. Irregular coil proteins (CAS) were more sensitive to ultrasound treatment and showed intense changes in secondary structure (e.g., 26.1% decrease in α–helix and 39.4% increase in random coil). In globular proteins, the smallest particle size (108 nm) of CPI limited the efficiency of ultrasound. The improvement in functional properties of proteins depended on the extent of structural modifications. The enhancement of functional properties improved the physicochemical stability of water–in–oil (W/O) emulsions (e.g., the turbiscan stability index of CAS–added emulsion was reduced by 2.33; the primary and secondary oxidation products of lipid oxidation were reduced by 16.96% and 17.31%). However, the effects of ultrasound–treated CPI on the physicochemical stability of W/O emulsions was not significant. For proteins with small particle size, future research could consider the application of chemical/enzymatic means in combination with ultrasound to enhance their performance. [Display omitted] •The ultrasound efficiency depended on the native conformation of proteins.•The smaller particle size of the protein limited the ultrasound efficiency.•Ultrasound treated proteins enhanced the physicochemical stability of W/O emulsion.