Molecular insights into heat-induced structural modifications of porcine myofibrillar proteins: integrating multimodal thermal processing and molecular dynamics simulations

Heat treatment is a crucial step in meat processing, which significantly affects the quality characteristics of meat products by altering the conformation of proteins. A systematic investigation was conducted to characterize the impact of three heat treatment methods—poaching (P), stir-frying (SF), and low-temperature long-time vacuum cooking (LTLT)—on porcine myofibrillar proteins. The results demonstrated that thermal processing induced protein oxidation and denaturation, with SF showing the most pronounced effects: the highest carbonyl content (5.29 μmol/mg) and lowest sulfhydryl content (29.18 μmol/mg). LTLT best preserved ionic and hydrogen bonds while exhibiting the weakest hydrophobic interactions. Secondary structure analysis revealed significant α-helix to β-sheet conversion, which was most evident in SF. Molecular dynamics simulations confirmed heating-induced myosin unfolding, showing increased root mean square deviation and β-sheet content alongside decreased hydrogen bonds and α-helix content. These findings offer molecular insights into heat treatment methods in meat processing, thereby enabling a more scientific selection of thermal processing strategies.