Multiscale mechanism of linolenic acid oxidation regulating gluten network formation

In this study, lipoxygenase (LOX), linolenic acid (LLA), and wheat gluten (WG) were used as raw materials to investigate the effects of LOX-mediated LLA oxidation on the structure and functionality of WG. The results revealed that the combination of LLA and WG led to changes in protein function and properties. Rheological analysis showed enhanced viscoelasticity and network structural strength under specific conditions (LLA addition at 0.1 mL/g, 45-60 min reaction time). Structural analysis revealed substantial conformational rearrangements, with decreases in endogenous fluorescence intensity, surface hydrophobicity, and WG extraction rate by 90.28 AU, 1.77 μg, and 184.61 AU, respectively. Disulfide bond content increased by 1.55 μmol/g, accompanied by a 14.77% increase in β-sheet content, suggesting enhanced intermolecular cross-linking. SDS-PAGE and size-exclusion HPLC confirmed the progressive formation of high-molecular-weight polymers. Levels of lipid oxidation products, including dityrosine, carbonyl compounds, and malondialdehyde, increased significantly, indicating deepened oxidation. Confocal laser scanning microscopy revealed a 56.51% reduction in protein network porosity, consistent with increased structural compactness. Overall, LOX-mediated LLA oxidation was associated with enhanced functional properties and network structure of WG, likely by influencing hydrophobic interactions and facilitating covalent cross-linking. This study provides insights into lipid-protein interactions and offers a basis for modulating WG functionality in food processing.