Effects of Toona sinensis seed polyphenols on pork myofibrillar protein oxidative modification, structure and physicochemical properties

This study was designed to investigate the effects of Toona sinensis seed polyphenols (TSSs) (0, 0.1, 0.3, 0.5, and 1.0%) on the structure and physicochemical properties of pork myofibrillar protein (MP) under the Fenton oxidation system. The results showed that the TSSs could suppress MP oxidation. Low concentrations of TSSs (0.1% and 0.3%) could cause a decrease in the content of carbonyl and dityrosine while reduce the loss of total SH, reactive SH, and free amino groups. However, high concentrations of TSSs (0.5% and 1.0%) were observed with opposite phenomenon for the above index. Meanwhile, the TSSs significantly improved the physicochemical properties of MP with better solubility, turbidity, particle size, and zeta potential observed at 0.3% treatment ( P < 0.05 ) compared to other groups. SDS-PAGE showed that TSSs could inhibit the polymerization primarily formed by MHC through S-S bonds, which was verified by nano LC-ESI-MS/MS analysis. Otherwise, TSSs could increase the α-helix content at moderate concentrations of TSSs (0.1% and 0.3%) but decrease the intrinsic fluorescence intensity and the surface hydrophobicity with increasing levels of TSSs. Thus, inhibited protein oxidation, and modified structure and physicochemical properties of MPs under the Fenton oxidation system can be better achieved by 0.3% TSSs. • TSSs at 0.3% could better inhibit MP oxidation under the Fenton oxidation system. • TSSs at 0.1% and 0.3% could modify physicochemical properties of MP. • TSSs could inhibit the polymerization primarily formed by MHC through S-S bonds.