Structure–Activity Relationships of Flavonoids in the Inhibition of Heterocyclic Amine Formation through Interactions with Beef Myofibrillar and Sarcoplasmic Proteins

Flavonoid-protein interactions mitigate the accumulation of heterocyclic amines (HAs) during heating. This study compared the effects of structurally diverse flavonoids (apigenin, luteolin, and diosmetin) on bound and free HA formation in myofibrillar protein (MP) and sarcoplasmic protein (SP) model systems and elucidated their interaction and HA-inhibition mechanisms. Luteolin showed the highest inhibitory activity, reducing the total bound HA content by 69.84% in MP and 61.15% in SP. Fluorescence quenching and molecular dynamics simulations revealed that luteolin binding was primarily driven by electrostatic interactions, whereas apigenin and diosmetin relied mainly on van der Waals forces. All flavonoids suppressed protein oxidation through noncovalent static quenching, thereby stabilizing protein conformations and modulating the accessibility of HA precursor and nonprecursor residues. In roasted beef patties, luteolin again showed the strongest HA suppression. These findings highlight that flavonoid, particularly luteolin, is a promising natural additive for enhancing the safety of heat-processed meat products.