Abstract
Myofibrillar protein (Mf) of scallop muscle was reacted with various concentrations of glucose at 50°C and different relative humidities (RH 5-95%), and the change in solubility of Mf in low- and high-ionic-strength media was investigated. When the lyophilized Mf-glucose mixture (Mf: glucose=1: 18) was reacted at RH 5% and RH 35%, the solubility of Mf in 0.1 M NaCl increased markedly and almost equaled the solubility in 0.5 M NaCl. However, the improvement of the solubility in 0.1 M NaCl diminished at RH 65% and almost disappeared at RH 95%. The suppression of the solubility at RH 65% and RH 95% was mainly caused by the loss of the intrinsic salt-solubility of myosin, regardless of the degree of the Maillard reaction. The loss of the salt-solubility of myosin during the reaction with glucose was effectively suppressed by controlling the relative humidity at less than 35% and increasing the glucose concentration to more than 0.08 mol/g H2O. These results indicate that the improvement of the solubility of Mf in a low-ionic-strength medium by the Maillard reaction with glucose is closely related to the salt-solubility of myosin, and the relative humidity and the glucose concentration are important factors in suppressing myosin heat denaturation.
