抄録
The protective effect of carboxylic acid and the joint protective effects of Various mixtures, which included carboxylic acids, sorbitol and Na-glutamate on the thermal stability of chub mackerel myofibrils have been studied by measuring the change in hte first order rate constant (kD) for inactivation of its Ca-ATPase.
Plotting the logarithm of kD against the concentration (0-1.5M) of carboxylic acid, a single linear relation was obtained. The slope (E) of the graph of log kD versus molarity of carboxylic acid revealed that the protective effect against the denaturation of myofibrils becomes lower in the order of: Na-citrate, Na-gluconate, Na-malate, Na-tartrate, Na-maleate, Na-fumarate, Na-succinate, Na-frmate. The protective effect of carboxylic acid was thus found to be roughly proportional to the numbers of COOH group in its structural formulas.
The decrease in log kD showed that the joint protective effects were nearly additional for all pair combination selected from among sorbitol, Na-glutamate and carboxylic acids. Consequently, the kD(a+b)=kDa•kDa/kDo assayed in the presence of two compounds can be estimated: the values obtained in the absence (kDo) and presence of compound a (kDa) and b (kDb), respectively.
