Identification of thermal degradation products of spice curcumin and their interactions with actin, collagen, and myosin using HPLC-Q-TOF-MS and molecular docking studies

Abstract

Meat represents a nutritionally dense food source, and the addition of flavor compounds can significantly influence its quality. Curcumin, a major antioxidant component of the spice flavor turmeric, undergoes thermal degradation during meat processing, generating bioactive derivatives that can interact with proteins. However, the interactions of native curcumin and its thermal degradation products with meat proteins remain incompletely understood. This study characterized the thermal degradation products of curcumin and investigated their interactions, along with those of native curcumin, with three key meat proteins: actin, collagen, and myosin. Twelve major thermal degradation products of curcumin were identified using HPLC-Q-TOF-MS/MS. Molecular docking simulations with actin, collagen, and myosin revealed that both curcumin and its degradation products form stable complexes (binding affinity: 4.0 to −9.1 kcal/mol) through multiple interaction modes, including hydrogen bonding, π-interactions, and hydrophobic contacts. Bicyclopentadione exhibited the highest binding affinity (−8.4 to −9.1 kcal/mol), forming seven hydrogen bonds with collagen. Compounds retaining the intact β-diketone moiety also demonstrated strong binding interactions. Three conserved binding hotspots were identified: Gln137 in actin, Arg41 in collagen, and Tyr134 in myosin. Notably, both curcumin and its degradation products exhibited distinct yet significant interactions with the different meat proteins. Some degradation products showed stronger binding to certain proteins than native curcumin, suggesting their potential to physically shield oxidation-prone residues. These findings provide crucial molecular-level insights into the interactions between curcumin derivatives and meat proteins, offering valuable clues for developing curcumin-based strategies to improve the quality of processed meat products.