Inhibition mechanism of different amino acids on the high-dose EGCG-induced deterioration of myofibrillar protein gelation

The role of L-Arg, L-His, and L-Pro in improving protein solubility and water retention of meat products has been extensively studied. However, it is not clear whether amino acids might inhibit interaction between protein and polyphenol to improve the protein structure, physicochemical and gel quality impairment caused by high dose Epigallocatechin-3-gallate (EGCG). Therefore, the aim of the study was to investigate the mitigating effects of L-Arg, L-His, and L-Pro on high-dose EGCG-induced Myofibrillar protein (MP) gelation deterioration and the mechanisms. EGCG may preferentially bind to three amino acids through hydrogen bonding, inhibiting excessive MP-EGCG interactions, especially with the addition of 20 mM L-Arg or 20 mM L-His. Amino content, thiol content, FTIR and molecular docking analyses supported the conclusion. Therefore, the addition of three amino acids alleviated the excessive aggregation of MP caused by EGCG, significantly improving MP solubility (p < 0.05) and rheological properties, which was beneficial to the formation of uniform and dense network structure in MP gel. As a result, MP gel loss was reduced from 54.4% to 35.2% - 45.95% (p < 0.05). In addition, L-Arg and L-His (20 mM) significantly increased the gel strength from 0.16 N to 0.24 N and 0.21 N, respectively (p < 0.05), whereas L-Pro did not have a significant improvement effect on the gel strength. The present study provided a strategy to mitigate polyphenol-induced damage to gel properties through the addition of amino acids, thereby improving the quality of meat products.