l-Arginine and l-lysine retard aggregation and polar residue modifications of myofibrillar proteins: Their roles in solubility of myofibrillar proteins in frozen porcine Longissimus lumborum

• Arginine (Arg) and lysine (Lys) alleviated the decline in myosin heavy chain density. • Arg and Lys abated the drop in myofibrillar proteins (MPs) solubility of frozen meat. • Arg and Lys alleviated the increase in the carbonyl content of MPs extract (MPE) • Arg and Lys abated the loss of free amino group and total sulfhydryl content of MPE. • Arg and Lys raised the temperature and enthalpy of the 1 st phase transition of MPE. This study investigated the ability of l -arginine and l -lysine to inhibit the adverse effects of freezing on the structure and solubility of myofibrillar proteins extract (MPE) in porcine Longissimus lumborum . The results showed that freezing decreased solubility of MPE, band densities of actin and myosin heavy and light chains, fluorescence intensity, and contents of free amino group and total sulfhydryls, but increased content of carbonyl groups and absolute zeta-potential of MPE. l -Arginine and l -lysine effectively alleviated the adverse effects of freezing. l -Arginine and l -lysine significantly increased β -sheet content, T max1 and ΔH 1 , but decreased α -helix content and disulfide bond content in MPE. Additionally, the SDS-PAGE analysis showed that l -arginine and l -lysine could prevent appearance of bands at about 150 kDa. Overall, this study shows that both l -arginine and l -lysine could not only abate the aggregation and disruption of MPs, but also reduce the oxidation of their polar amino groups, which ultimately contribute to their superior solubility. The results may be interesting in meat industry.