Rheological properties of heat-induced gels of myosin solubilized in a low ionic strength solution containing L-histidine

摘要

Myosin is generally considered to be insoluble in a low ionic strength solution. However, we have shown that myosin is solubilized in a low ionic strength solution containing L-histidine. To clarify its processing characteristics, we investigated rheological properties and structures of heat-induced gels of myosin solubilized in a low ionic strength solution. Myosin in a low ionic strength solution containing L-histidine formed transparent gels at 40-50°C, while myosin in a high ionic strength solution formed opaque gels at 50°C or more. The former showed a fine network consisting of thin strands, and the latter showed a coarse and porous network by SEM. Dynamic rheological analysis showed that the storage modulus of myosin in a low ionic strength solution increased drastically from 45°C up to 50°C, while that in a high ionic strength solution increased drastically from 45°C up to 75°C. The loss tangent of heat-induced gel of myosin in a low ionic strength solution was 0.23, while that of myosin in a high ionic strength solution was 0.08. The heat-induced gel of myosin in a low ionic strength solution is a "weak gel" and less elastic than that of myosin in a high ionic strength solution.