Self-Assembled Wheat Gluten Peptide Nanoparticles as Dual-Functional Stabilizers for the Protection of Omega-3 Polyunsaturated Fatty Acids

Omega-3 polyunsaturated fatty acids are highly susceptible to oxidation, limiting the shelf life and sensory quality of omega-3-fortified foods. Herein, wheat gluten peptide nanoparticles (WGPNs) with coupled emulsifying and antioxidant functions were produced by sequential pepsin-trypsin hydrolysis. LC-MS/MS showed a peptide pool (1-4 kDa) enriched in Gln/Pro, featuring hydrophobic motifs and C-terminal Lys/Arg residues that confer surfactant-like behavior. WGPNs formed spontaneously in aqueous media, mainly driven by hydrophobic association and hydrogen bonding, with concentration-dependent β-sheet formation and a critical aggregation concentration of ∼0.17 mg/mL. Above this threshold, WGPNs exhibited enhanced radical-scavenging activity and colloidal stability across a wide ionic-strength range. Interfacial measurements demonstrated rapid adsorption of WGPNs at the oil-water interface, reduced interfacial tension, and formation of a stable interfacial layer. Consequently, WGPNs effectively stabilized fish oil emulsions and markedly retarded lipid oxidation. This work establishes WGPNs as a clean-label, dual-function platform for protecting oxidation-sensitive lipids in food systems.