α-Tocopherol and naringenin in whey protein isolate particles: Partition, antioxidant activity, stability and bioaccessibility

Food proteins are being used as carrier materials for the co-encapsulation of bioactive components. Partition of bioactive components in a carrier depends on their solubility and interaction with carrier materials. In this study, hydrophobic α-tocopherol and amphiphilic naringenin were chosen as model bioactive components to construct their complex nanoparticles with whey protein isolate (WPI). Naringenin in the molecular level was bound to WPI particles, while α-tocopherol was both bound in the molecular level and encapsulated as the aggregate in the particles. In ternary complex particles, the increased antioxidant activity of WPI-naringenin particles counteracted the protein shielding effect on the activity of α-tocopherol. Oxidation of α-tocopherol and naringenin did not cause any damage to WPI, but slightly changed the size and ζ-potential of protein particles during storage. Addition of naringenin improved the stability and bioaccessibility of α-tocopherol. The data gathered here would provide guidance for the development of protein-based co-encapsulating carriers.