Pickering emulsion gels stabilized by high hydrostatic pressure-induced whey protein isolate gel particles: Characterization and encapsulation of curcumin

In this study, whey protein isolate (WPI) gel particles were fabricated via high hydrostatic pressure (HHP) treatment and homogenization and the potential of using the particles as food-grade stabilizers to form Pickering emulsions and emulsion gels were studied. The result showed that pH had a significant effect on the properties of WPI gel particles. In the pH range near the isoelectric point (pI) (around pH 5.0), the particles exhibited spherical structure with larger size. The droplet size, creaming stability, microstructure and rheological properties of the Pickering emulsions stabilized by the WPI gel particles were influenced by pH and ionic strength, particle concentration and oil fraction. Pickering emulsion gels were formed from the Pickering emulsions stabilized by the particles at pH 5.0 after storage for 3 days at room temperature (25 degrees C). Confocal laser scanning microscopy (CLSM) demonstrated that the WPI gel particles formed a densely packed particle layer on the surface of oil droplet, suggesting the potential of these particles as Pickering emulsion stabilizers. Besides, the Pickering emulsion gels had the highest loading efficiency of curcumin and best stability against light degradation.