Novel insights into the binding mechanisms of selected aldehydes during heat-induced protein unfolding

This investigation aimed to clarify the binding mechanisms between six aldehydes and myofibrillar proteins (MPs), with a structural explanation in response to stage-heating treatments. The conformational intermediates of MPs, which form during heat processing, were systematically characterized to elucidate their role in aldehyde binding and flavor retention. Machine learning results suggested that high-temperature boiling promoted extensive protein denaturation and aggregation, while subsequent low-temperature stewing induced partial rearrangement. Thermodynamic parameters indicated that hexanal-MPs formation was primarily driven by hydrogen bonding, whereas other longer-chain and unsaturated aldehydes penetrated hydrophobic pockets. Proteomics revealed that saturated aldehydes predominantly formed Schiff bases with the lysine ε-amino group. Unsaturated aldehydes, especially (E, E)-2,4-decadienal, undergo both Schiff base reactions and Michael addition with cysteine, histidine, and tryptophan residues. The retention/release behavior of aldehydes during processing is determined by covalent and non-covalent interactions. These results provide a scientific basis for precisely controlling flavor quality in meat products.