Zn(II) - mediated self-assembly of neohesperidin-soy protein isolate nanoparticles and their antioxidant performance

Neohesperidin (NH), a citrus-derived flavonoid glycoside, is limited by poor water solubility and biological instability. To address this, a novel Zn(II)-mediated self-assembly strategy was developed to fabricate NH-soy protein isolate (SPI) nanoparticles. Driven by hydrogen bonding and hydrophobic interactions, NH and SPI formed cross-linked composite structures. Structural analysis via DSC and secondary structure characterization revealed a 39.8 °C increase in thermal stability and an 8.4 % rise in α-helix content, indicating strengthened conformational stability through Zn(II) coordination. Antioxidant assays showed the nanoparticles exhibited a 20.0 % higher DPPH radical scavenging efficiency and 13.9 % enhanced ferric reducing capacity compared to Zn(II)-free controls. Collectively, these results demonstrate that the Zn(II)-mediated nanoparticle system effectively improves both the stability and antioxidant performance of NH, offering a promising approach for designing flavonoid-based functional materials in food and pharmaceutical applications.