Effect of salmon protamine on the physicochemical properties of porcine myofibril

Though salmon protamine (PRO) is known to exhibit strong antibacterial action, the effect of PRO on the physicochemical properties of porcine myofibril (Mf) are not yet fully understood. In this study, we investigated the effect of PRO on the rheological properties of Mf proteins. The viscosity of the Mf homogenate decreased with increasing PRO in a concentration-dependent manner. The breaking stress of the thermal gel was reduced in the presence of PRO. Scanning electron microscopy examination showed that PRO had a 3-dimensional network structure with thread-like protein filaments. SDS-PAGE analysis demonstrated that myosin binding protein-C and myosin light chain 1 in Mf were solubilized by the addition of PRO. However, PRO inhibited the solubilization of α-actinin. These results showed that PRO had an adverse effect on the gelling properties of porcine Mf through the protein-protein interaction between PRO and Mf proteins.