Maltodextrin-shielded pumpkin seed protein nanoparticles formed by Maillard-induced protein modification for oral pterostilbene delivery.

Plant protein nanoparticles represent promising oral carriers for hydrophobic bioactives in functional foods, yet their poor dispersibility and gastrointestinal instability limit delivery efficacy. In this study, maltodextrin (MD) was covalently conjugated with pumpkin seed protein (PP) through wet-heating glycation to construct a core-shell nanocarrier for oral pterostilbene (PTE) delivery, designated as PTE@P-M. The glycated MD-derived shell markedly improved PP solubility, reduced turbidity, and moderated surface hydrophobicity, indicating substantial remodeling of PP physicochemical properties. PTE@P-M exhibited an encapsulation efficiency of 94.47 ± 3.96% and a particle size of 249.3 ± 18.0 nm. Relative to PTE-loaded heat-treated PP (PTE@H-P), PTE@P-M retained more PTE under thermal, acidic, and Ca2+ stress conditions and demonstrated improved in vitro digestion behavior and release kinetics. Interaction analysis and molecular docking indicated that non-covalent interactions collectively contributed to PTE stabilization within the glycated matrix. In vivo, PTE@P-M increased oral bioavailability by 3.1-fold relative to free PTE and by 1.3-fold relative to PTE@H-P. The enhanced biological efficacy of PTE@P-M was further validated in a dry eye disease model, as evidenced by increased tear secretion and alleviated ocular surface damage. Collectively, Maillard-induced MD conjugation generated a protein-core/carbohydrate-shell nanoarchitecture that enhanced PTE stability, gastrointestinal performance, and oral bioavailability.