Abstract
The effect of the unfrozen phase under frozen storage conditions on the solubilty and ATPase activity of carp myofibrils was compared. Myofibrillar samples were suspended in 0.1M KCl solution containing 5 and 20mM Tris-maleate buffer (pH 7.2), and in 0.1M KCl solution without a buffer. Sampleswere stored at threedifferent temperatures, -4, -11, and -26°C. When the decrease in ATPase activitywas larger than that of the soluble protein during storage above and nearthe eutectic point of KCl (at-4 and -11°C), and in the presence of 20mM Tris-maleate buffer, it is assumed that the myofibrils are greatly affected by a small amountoof concentrated KCl solution. However, in the absence of a buffer, Where the opposite occurs in both indices, the denaturation of myofibrils is thought to be caused largely by the moving closer together and maldistribution of protein molecules. This is possible to explain in terms of the amount of unfrozen solution being sufficient for maldistribution, but insufficient for inactivation. On the other hand, when stored below the eutectic point of KCl (at-26°C), the decrease in both indices was smaller than that seen in samples stored at -4 and -11°C.This could be ascribed to the fact that myofibrillar protein and crystallized KCl are dispersed uniformly due to the small amount of unfrozen solution, insufficient for bothmaldistribution and inactivation. The surface hydrophobicity was increased in the early stages of storage at both-4°C and-11°C.
