A mechanistic investigation of the effect of dispersion phase protein type on the physicochemical stability of water–in–oil emulsions

In this study, effects of two animal–based and two plant–based proteins on the stability of W/O emulsions were evaluated. On physical stability, turbiscan stability index values showed that the trend of protein–added emulsion followed the order: whey protein isolate (WPI) < sodium caseinate (CAS) < pea protein isolation (PPI) < chickpea protein isolation (CPI). On chemical stability, the inhibition of lipid oxidation followed the order: CPI < CAS < WPI < PPI. The particle size, zeta potential, ability to increase emulsion viscosity and interfacial adsorption of proteins affected the emulsion physical stability. Among the effects of chemical stability, antioxidant properties, physical barrier effects and transition metal ion binding capacity were crucial for lipid oxidation. In improving the stability of W/O emulsions, we found great potential of CPI and PPI for the future combined application of both and to improve the stability of W/O emulsions.