Effects of High Pressure on the Myofibrillar Proteins of Cod and Turkey Muscle

When turkey breast muscle and isolated myofibrillar protein and myosin of cod or turkey (pH ≈7) were subjected to pressures up to 800 MPa for 20 min, DSC and electrophoresis (SDS−PAGE) indicated that high pressure-induced denaturation of myosin led to the formation of structures that contained hydrogen bonds and were additionally stabilized by disulfide bonds. Disulfide bonds were also important in heat-induced myosin gels. Hardness of whole cod muscle, estimated by texture profile analysis, showed pressure-treated samples (400 MPa) to be harder than cooked (50 °C) or cooked and then pressure-treated or pressure-treated and then cooked samples, supporting the suggestion that pressure induces the formation of heat labile hydrogen-bonded structures while heat treatment gives rise to structures that are primarily stabilized by disulfide bonds and hydrophobic interactions. As expected, turkey myosin is more stable than that of cod; however, it seems their pressure-induced gelation mechanisms are similar. Keywords: High-pressure treatment; myosin gelation; cod myofibrillar proteins; turkey myofibrillar proteins; protein denaturation; DSC; TPA; electrophoresis