CaCl₂ supplementation of hydrophobised whey proteins: Assessment of protein particles and consequent emulsions

Hydrophobised whey protein particles were prepared through successive acetylation and heat treatment practices, and the particle characteristics were modulated by CaCl₂ supplementation. Then, the usefulness of the hydrophobised protein particles for emulsification of a docosahexaenoic acid-rich oil was compared with that of heat-denatured whey protein. Addition of CaCl₂ into hydrophobised whey protein resulted in smaller protein particles and lower ζ-potential and interfacial tension values. It also decreased the creaming stability of the consequent emulsions. It was argued that besides Ca²⁺-protein charge interactions, Cl^– anions bind to the hydrophobised particles, and the Pickering stabilisation of oil does not rely on interfacial tension reduction. Compared with heat-denatured whey protein, hydrophobised whey protein afforded a lower protection to oil against oxidation; the peroxide value of the oil emulsified using hydrophobised protein was higher during storage.