Abstract
Applicability of a coagulation test was evaluated for the determination of the previous heat condition of heated blue marlin meat. Meat blocks were heated at different temperatures between 50 and 70°C. Proteins were extracted with different concentrations of NaCl, then subsequently subjected to the coagulation test. The coagulation method was able to determine the end-point temperature (EPT) of heated blue marlin meat within a range of 1-2°C, up to 67°C. The best correspondence between the actual EPT and coagulation temperature of the filtrates was found when proteins were extracted with 0.9% saline solution. Within the range of 50-67°C, sample preparation methods and holding times had no significant effect on the coagulation temperature of the filtrates. Protein bands of the filtrates on sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel gradually disappeared with increasing temperature. One band with a molecular weight of about 31 kDa was detected in 67°C-, but not in 70°C-heated meat. This protein component was responsible for coagulation at 67°C and was found to be lactate dehydrogenase from the analyses by gel filtration, SDS-PAGE, and enzyme activity.
