Self-assembling wheat gluten peptide nanoparticles: Pterostilbene encapsulation and interaction mechanism

Abstract

In this study, the wheat gluten protein peptide WGP-M (3697.86 Da) was used as a carrier to successfully prepare pterostilbene (PTE) composite nanoparticles (WGPM-PTE), and the self-assembly mechanism and structural characteristics were thoroughly investigated. The composite nanoparticles were systematically characterized using HPLC, SEM, SAXS, XRD, FTIR, and DLS. WGPM-PTE exhibited an excellent encapsulation efficiency of 90.89% and solubility of 113.56%. SEM images revealed that WGPM-PTE had a dense gel-like network structure with a smooth surface, while SAXS confirmed its highly ordered and stable internal structure, showing a minimum radius of gyration (3.16 nm) and maximum rigidity. XRD analysis revealed that the crystalline peaks of PTE in WGPM-PTE disappeared completely, indicating an amorphous state. Furthermore, FTIR spectra, fluorescence spectra, and thermodynamic parameter analysis revealed that WGP-M and PTE primarily formed stable non-covalent interactions through hydrogen bonding, van der Waals forces, hydrophobic interactions, and electrostatic forces. Molecular dynamics simulations showed that PTE was encapsulated in the hydrophobic core of WGP-M. In conclusion, this study elucidates the interaction mechanism by which the self-assembly capacity of WGP-M facilitates the loading of PTE, offering new insights for the development of novel food-derived peptide-based nanoparticle carriers with significant potential for practical applications.