Impacts of kaempferol on α-dicarbonyls mediated protein modification during simulated heat-treatment of β-lactoglobulin.

Thermal processing of dairy products generates α-dicarbonyl compounds such as methylglyoxal (MGO) and glyoxal (GO), which are key precursors of advanced glycation end products (AGEs). This study presents an integrated assessment of kaempferol (Kae), a flavonol polyphenol, in modulating MGO/GO-mediated AGEs formation and physicochemical alterations in β-lactoglobulin (β-LG). Kae (0.1-2 mM) dose-dependently reduced MGO/GO (1 mM)-mediated formation of fluorescent-AGEs and glycoxidation products. Further loss of protein sulfhydryl content, surface hydrophobicity and intrinsic tryptophan fluorescence were observed at Kae concentration of 2 mM, showing concentration-related dual effects of Kae. Western blot analysis revealed the binding of MGO/GO to β-LG was interrupted by Kae. Targeted sequestration of MGO resulting in the formation of mono-/di-MGO-Kae was confirmed by LC/MS. Molecular docking simulation showed Kae's preferential binding to β-LG, shielding potential glycation sites from MGO/GO. These findings collectively suggest a mitigation strategy utilizing phenolic nucleophiles to counteract MGO/GO-mediated modifications in dairy proteins.