Hydroxytyrosol-loaded zein nanoparticles: A green formulation for pharma/nutraceutical applications

This study describes an environmentally friendly and low-cost strategy to preserve the bioactivity of hydroxytyrosol, a phenolic molecule proposed for the enrichment of functional foods, characterized by a poor absorption and a rapid metabolism. The encapsulation of the natural compound within zein nanoparticles was employed to address these limitations, obtaining nanosystems with ∼100 nm diameter, a narrow size distribution, a negative zeta potential and a high entrapment efficiency. The formulations demonstrated to be stable after pasteurization and under ionic strength up to 100 mM NaCl, while FT-IR analysis showed hydrogen bonding as the key interaction driving zein–hydroxytyrosol association. Simulated gastrointestinal studies demonstrated that the nanocarriers protected hydroxytyrosol from degradation, while its antioxidant activity was preserved as confirmed by in vitro tests and ORAC assay. These results underline the potential of hydroxytyrosol-loaded zein nanoparticles as a versatile platform for nutraceutical applications and functional food fortification.