Construction of fucoxanthin-loaded multi-functional pea protein isolate-fucoidan nanoparticles at neutral pH: Structural characterization and functional verification

Fucoxanthin (FX), a marine-origin carotenoid, possesses various physiological activities. However, FX has instability and low water solubility. Encapsulation using nanoparticles effectively addresses these challenges. Nanoparticles loaded with FX were fabricated using a pH-driven method, with pea protein isolate (PPI) and fucoidan (FUC) serving as the raw materials. The optimal nanoparticles were prepared at pH = 7.0 with a PPI:FUC = 1:3, yielding a particle size of 166.60 ± 0.55 nm and a zeta potential of −40.88 ± 0.68 mV. The formation of FX@PPI/FUC nanoparticles were primarily driven by hydrogen bonding and hydrophobic interactions. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and fluorescence spectroscopy were used to research structure of nanoparticle and interaction during the formation. The FX@PPI/FUC nanoparticles demonstrated excellent thermal and pH stability in neutral and alkaline environments, effectively released FX and showcased antioxidant properties. Additionally, a W/O/W FX@PPI-FUC Pickering emulsion was formulated, containing 65 % of the oil phase, which exhibited a favorable particle size of 26.5 ± 0.28 μm and a zeta potential of −67.2 ± 0.94 mV. Furthermore, the FX@PPI-FUC Pickering emulsion demonstrated outstanding thermal and storage stability, indicating its potential for application in functional food.