Physicochemical and structural characterization of self-assembled nanoparticles from whey protein isolate-dextran
Chen Huang1, Xinjing Li1, Guzalnur Askar1
1School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, PR China.
Abstract:
Given the poor water solubility and limited bioaccessibility of capsaicin, this study aimed to develop whey protein isolate-dextran Maillard conjugate-based nanoparticles and clarify their structural characteristics and interaction mechanism with capsaicin. Ultrasound-assisted self-assembly yielded nanoparticles with a diameter < 210 nm, polydispersity index <0.30, and encapsulation efficiency of 61.8 ± 1.2%. Multi-spectroscopic characterization, thermodynamic analysis, molecular dynamics simulation, and molecular docking were employed to characterize nanoparticle evolution and capsaicin-conjugate interactions. Ultrasound induced relaxed conformations that favored capsaicin incorporation. Scanning electron microscopy and X-ray diffraction provided indirect evidence supporting capsaicin loading. Fluorescence quenching and thermodynamic analyses indicated hydrophobic interaction-driven static complex formation, whereas molecular docking identified binding sites, and molecular dynamics simulation confirmed conformational stability of the conjugate model. Encapsulation improved the bioaccessibility of capsaicin from 23.23% to 66.54% during in vitro digestion. These findings provide a mechanistic basis for designing polysaccharide-protein conjugate carriers for hydrophobic bioactives.
