Furthermore,zinc salt at high concentration(80 mmol/kg) might inactivate endogenous transglutaminase,thus preventing polymerisation via non-disulphide covalent bonds. reported that tilapia TGase was inhibited by 10 mM Zn2+. Additionally,the coagulated proteins induced
by excessive Zn2+ might not have the reactive groups,lysine and glutamine, available for transglutaminase. This might result in the lower setting,which was concomitant with poor
gel properties as indicated by low breaking force and deformation(Fig.1). High zinc salt content possibly inactivated endogenous proteases at some degree,resulting in low degradation
of MHC as evidenced by the higher MHC band intensity retained. Zn2+ has been reported as a potent inhibitor of several proteases, e.g.calpains. ZnCl2 in fusion blocked postmortem
proteolysis and tenderization of ovine carcasses because Zn2+ inhibited both calpains and cathepsins B and L activities(Koohmaraie,1990).