Cooking mediated wheat gluten aggregation behavior: Physicochemical properties and component changes

Changes in the physicochemical properties of wheat gluten (WG) during cooking are mainly dependent on its intramolecular and intermolecular interactions when subjected to high-temperature treatment. In this study, the effects and mechanisms of cooking on the aggregation behavior of WG were investigated. Results showed that an increase in cooking time led to an initial increase and subsequent decrease in WG viscoelasticity, with optimal viscoelastic properties observed at 5 min. As cooking proceeded, covalent cross-linking of WG deepened and the contribution of hydrogen bonds to maintaining WG structure weakened, while the contribution of hydrophobic interactions strengthened. Cooking increased the proportion of gauche-gauche-gauche in the disulfide (SS) bridge conformation and decreased the homogeneity of the WG network. The unfolding of gluten molecules caused by hydrogen bonds breaking and intermolecular cross-linking through hydrophobic interactions and SS formation jointly contributing to the rheological properties of WG. Notably, glutenin (Glu) exhibited more similar physicochemical changes to WG during cooking than gliadin (Gli). Glu was more sensitive to cooking than Gli and formed dense, continuous aggregates prior to Gli. Cross-links formed by Glu occupied the majority of three-dimensional network of WG, while Gli was involved only in the form of branched chains. This may explain why Glu dominates the physicochemical changes of WG during cooking. This study contributes to a deeper understanding of the thermal denaturation mechanism of WG and provides new insights into the processing of flour-based foods.