Fabrication, characterization, physicochemical stability and simulated gastrointestinal digestion of pterostilbene loaded zein-sodium caseinate-fucoidan nanoparticles using pH-driven method

Pterostilbene is a hydrophobic phytochemical with extensive potential physiological functions. However, the incorporation of pure pterostilbene into functional foods or pharmaceutical formulations is limited by its poor water solubility and stability. Therefore, this study aimed to fabricate effective nanoparticles to encapsulate pterostilbene. A simple pH-driven method was applied to fabricate zein-sodium caseinate-fucoidan composite nanoparticles, and pterostilbene was loaded into these nanoparticles. The effect of weight ratios of zein/sodium caseinate and sodium caseinate/fucoidan on the physicochemical characteristics of the composite nanoparticles was examined. The optimal zein/sodium caseinate/fucoidan weight ratio was 1:1:1. The pterostilbene-zein-sodium caseinate-fucoidan (PTE-zein-SC-FD) nanoparticles exhibited globular microstructures formed primarily through hydrophobic, electrostatic, hydrogen-bonding, and steric interactions, with an average particle size of 62.3 nm, ζ-potential of −29.1 mV, and encapsulation efficiency for pterostilbene of 95.2%. Moreover, sodium caseinate and fucoidan synergistically enhanced the physicochemical stability of pterostilbene-loaded zein-based nanoparticles. PTE-zein-SC-FD nanoparticles showed excellent colloidal stability under broad-range pH values (2.0–8.0), elevated salt concentrations (0–3.0 mol/L NaCl), and simulated gastrointestinal conditions. Meanwhile, PTE-zein-SC-FD nanoparticles exhibited higher encapsulation efficiency and in vitro bioaccessibility of pterostilbene, as well as provided better protection for pterostilbene under UV-irradiation and long-term storage conditions than other formulations or control groups. Furthermore, the fabricated zein-based composite nanoparticles could control and modulate the release of pterostilbene during the in vitro digestion. Additionally, zein-SC-FD ternary nanoparticles showed excellent biocompatibility, as assessed using a cytotoxicity assay. These findings demonstrate that zein-SC-FD nanoparticles can serve as an efficacious nanocarrier for the encapsulation, protection, and delivery of pterostilbene.