Short Thermal Treatment Effect on Carp Myofibril and Sarcoplasmic Reticulum: Possible Mechanisms in Rigor Mortis Acceleration by “Arai” Treatment

Abstract

Inorganic y-phosphate liberation from adenosine S&phosphate (ATP) by carp myofibrillar ATPase was measured at 0-6O"C to elucidate mechanisms in rigor mortis acceleration of sliced carp muscle during washing at a moderately high temperature. ATP splitting within 20 set in the presence of 5 mM MgCla plus 0.25 mM CaCla was maximal at 45"C, which agreed well with the commercially adopted condition for preparing carp "arai" muscle. In addition, the maximum Caz+ uptake by sarcoplasmic reticulum was observed at 30°C and decreased at higher temperatures. The acceleration of carp muscle rigor mortis at around 45°C was suggested to be partly due to enhancement of myofibrillar Mg2+-ATPase activity by increase of intracellular Ca2+ concentration.