Background: Phenolic acids are antioxidant nutrients in cereals and affect the quality of wheat products and the properties of gluten protein. Gallic acid (GA), caffeic acid (CA), syringic acid (SA), and p-coumaric acid (p-CA) were selected to study the interaction mechanism between cereal phenolic acids and gluten protein.
Results: The results showed that adding GA significantly (P < 0.05) decreased the content of free sulfhydryl in gluten proteins by 70-87.26% compared with the control group. The aggregates' behavior of gluten protein induced by adding the phenolic acids would produce oversized particles (>5000 nm). Adding the selected phenolic acids changed the hydrogen-bond linkage of protein secondary structure. Zeta potential values of gluten protein increased significantly (P < 0.05) by 14.41%, 26.49%, 30.77%, and 57.93% for CA, p-CA, GA, and SA respectively added at 0.03 g kg-1 . Moreover, the gluten protein surface hydrophobicity increased when the phenolic acids were added at 0.03 g kg-1 , displaying the effect of the phenolic acid on the hydrophobic interaction of protein. Molecular docking results showed that the selected phenolic acids could interact with glutenin and gliadin using hydrogen-bond formation, and SA had the strongest binding with glutenin and gliadin.
Conclusion: The results demonstrated that the selected phenolic acids could interact with gluten protein via covalent cross-linking as well as by hydrogen bonding, thereby changing the structure of the gluten protein. This exploration is expected to provide theoretical support for the development and utilization of whole-grain foods. © 2022 Society of Chemical Industry.
Keywords: free sulfhydryl; gluten structure; hydrogen bond; molecular docking; secondary structure; zeta potential.
© 2022 Society of Chemical Industry.