The effects of HYP (10, 50, and 250 μM/g protein) on the physicochemical and gel properties of myofibrillar proteins (MPs) at different NaCl concentrations under oxidative stress were explored. The incorporation of HYP significantly reduced carbonyl content and decreased the loss of free amine groups in a dose-dependent manner, regardless of NaCl concentration. In addition, HYP induced a dose-dependent decrement in total sulfhydryl content regardless of NaCl concentration, which might result from the formation of thiol-quinone adducts via Michael addition. The surface hydrophobicity was significantly increased with HYP addition. Nevertheless, compared with samples treated with 50 μM/g HYP, 250 μM/g HYP caused a significant decrease in surface hydrophobicity, which might be due to the increase in the extent of MPs unfolding and the concomitant aggregation of MPs by hydrophobic interaction. Furthermore, HYP also showed a dose-dependent increment in the water-holding capacity (WHC) and gel strength of MPs gels, which might be due to more orderly crosslinks via fibrous filaments at 0.2 M NaCl and more regular and lamellar structures with smaller and more homogeneous pores at 0.6 M NaCl. In summary, HYP reduced the oxidation-mediated changes of physicochemical characteristics, preventing the oxidative damage of MPs and reinforcing the ordered crosslinks of MPs-MPs and MPs-HYP during thermal gelation, ultimately resulting in a better gel quality. These results provide a theoretical support for the practical application of HYP as a natural antioxidant in gel-type meat products.
Keywords: HYP; gel properties; myofibrillar proteins; oxidative characteristics.