Study on the interaction between epicatechin gallate and bovine myosin and its enhancement of protein structure and function

Bovine myosin is a critical protein influencing meat product quality, yet its conformation is susceptible to destabilization during processing. This study investigated the interaction mechanism between epicatechin gallate (ECG) and bovine myosin, as well as its regulatory effects on protein structure and functional properties. Spectroscopic analyses revealed that ECG bound to myosin through static quenching, altering the microenvironment of aromatic amino acid residues. FTIR further showed that ECG induced protein secondary structure rearrangement and promoted the formation of β-sheet structure. Molecular simulation revealed that hydrogen bonds and hydrophobic interactions were the dominant forces for stabilizing ECG-myosin binding. Glu331, Ile326 and Asp242 were identified as the key residues for the stable binding of the complex. Interestingly, at an ECG concentration of 100 μmol/L, the polyphenol binding rate reached 25.76%, DPPH radical scavenging capacity increased by approximately 5.2-fold, surface hydrophobicity markedly decreased, and solubility was enhanced by nearly 6-fold. In vitro digestion experiments showed that ECG delayed protein hydrolysis in the gastric phase but promoted both protein digestion and polyphenol release in the intestinal phase. Collectively, ECG significantly improved the physicochemical and functional properties of bovine myosin, and providing a scientific basis for the application of tea polyphenols in meat protein systems.