Gel forming ability of fish meat oxidized during washing

ABSTRACT: In order to examine the effect of meat oxidation on the gel forming ability before grinding the meat with salt, fish meat was washed with CuCl₂ solution, and the gel strength as well as total sulfhydryl (SH) groups and sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns were analysed. Washing with CuCl₂ solution resulted in a decrease in the total SH content of fish meat and the formation of myosin heavy chain (MHC) dimer through disulfide bonding. The plot of logarithmic gel strength versus protein concentration after heating the washed meat at 80°C in the presence of 3% NaCl to form a gel illustrated that the gel forming ability of meats washed with CuCl₂ solution was weaker than the control meat. The gel of meat washed with CuCl₂ showed the polymerization of MHC and MHC dimers through disulfide bonding much more than the control meat gel, although a small decrease in the SH group content after heating. Further washing with ethylene diamine tetra-acetic acid (EDTA) solution to remove CuCl₂ from the CuCl₂-washed meat also resulted in similar behavior for MHC polymerization and SH content as the CuCl₂-washed meat, and the gel was still weaker than the control gel. It was found that the oxidation of SH groups during washing with CuCl₂ solution accompanied by MHC dimer formation in the meat results in the weakening of its gel forming ability.