Differential scanning calorimetric studies on thermal behaviors of myofibrillar proteins

To obtain basic knowledge for processing of the meat products, such as, kamabokos, sausages, and hams, the myofibrillar proteins of rabbit, carp, and scallop were isolated and submitted to the differential scanning calorimetry (DSC). Myosin preparations gave broadly dispersed endothermic regions in each of which a peak was found at 62°C for rabbit(R), 50°C for carp(C), and 40°C for scallop(S). LMM's gave a single peak at 60°C(R)and 47°C(C). The peaks of myosins reflected the denaturation of the LMM portion of the myosin molecule. Actins showed a peak at 82°C(R), 75°C(C), and 77°C(S). In the crude actin, the actin's peak was accompanied by a peak at 58°C(R), 53°C(C), or 42°C(S), each of which was attributed to the regulatory proteins. The natural actomyosin preparations illustrated 2 peaks at 49°C and 62°C for rabbit and 41°C and 52°C for scallop, but that of carp gave 3 peaks at 43°C, 53°C, and 68°C. Each second peak was ascribed to myosin. None of the rest were found to be correlatable with any of the actin, myosin, or the regulatory proteins and thus these peaks were assigned to some conjugate derivatives of actin and myosin. The peak top temperatures, i.e., the heat denaturation temperatures, of the respective proteins were found to be different for the different animal species and an order of “rabbit, carp, and scallop” was commonly observed with a little exception in the case with scallop actin. The former descreasing order was related to the order of the habitat temperatures of the tested animals.