Whey protein isolate–phytosterols nanoparticles: Preparation, characterization, and stabilized food-grade pickering emulsions

The preparation of whey protein isolate (WPI) particles by heat induction usually reduces both protein nutritional value and functionality. In this study, WPI and phytosterols (PSs) were used to prepare whey protein isolate-phytosterol (WPS) nanoparticles as stabilizers of oil-in-water Pickering emulsions, and the effects of PSs on the structure and function of the nanoparticles were studied. The results showed that the WPI and PSs combine through non-covalent bonding, which alters the nanoparticle structure and function. When the WPI/PSs mass ratio was 25:2, the nanoparticles (WPS-4) exhibited excellent interfacial wettability, emulsification stability, and antioxidant activity. The nanoparticles formed thick and dense interfacial films on the droplet surfaces to protect them, and the emulsion stabilized with the WPS-4 nanoparticles exhibited the best storage stability and oxidation stability. The emulsion can also reduce the digestion of lipids. These results provide a theoretical basis for the application of WPS nanoparticles.