VARIATIONS OF TENSILE-STRENGTH OF MYOSIN GEL BY HEATING

The variations of the tensile strength of myosin gel during heating we re measured based on an equation, which was derived from the thermodyn amics of elastic deformation, in order to clarify the mechanism of the elasticity of kamaboko. Myosin was extracted from the croaker Nibea m itsukurii, and 85 mg protein/g gel/0.6 M KCl was prepared by heating a t 80 degrees C for 20 min. The myosin gel was extended to twice its or iginal length, and successively heated by an electric heater alone or in combination with an infrared ray. A commercially available kamaboko and a rubber band were also submitted to the experiments to compare w ith the myosin gel. The tensile strength of both myosin gel and kamabo ko increased and immediately decreased when these gels were heated by the electric heater and it continuously decreased with heating by an i nfrared bulb. In the case of rubber, on the other hand, the tensile st rength increased continuously. From the results of myosin gel and kama boko, the entropy of these gels was found to increase with elongation under a constant temperature. Hence, both myosin gel and kamaboko were found to have another mechanism for elasticity, different from that o f rubber, or entropy elasticity. As a result, myosin gel was concluded to be an energy elastic body, not an entropy one.