抄録
A new attempt was made to evaluate the quality of frozen surimi from Alaska pollack. The evaluation was achieved by measuring the ATPase total activity of myofibrils prepared quantitatively from frozen surimi. The quantitative method for preparation of myofibrils was as follows: Five grams of minced surimi was homogenized in a Universal homogenizer (NIHON SEIKI, HB) with 15ml of 0.1M KCl containing 40mM borate buffer (pH 7.0) for 1min at 20, 000rpm of the rotary cutter. The homogenization was repeated 5 more times with each interval of 30 sec. each. After addition of 85ml of the same 0.1M KCl (pH 7.0), the homogenate was centrifuged at 2, 400rpm for 10min. The pellet from this spin was resuspended in 20 volumes of 0.1M KCl (pH 7.0) and centrifuged for 10min at 2, 400rpm. The suspension and centrifugation were repeated 5 more times. The pellet obtained was finally suspended in 100ml of 0.1M KCl (pH 7.0) using the glass homogenizer and used for the measurement of the Ca2+-and Mg2+-ATPase total activities.
The myofibrillar ATPase total activities from frozen surimi of grades C, A, and SA gave average values of 102±15, 136±18, and 175±11 for Ca2+-ATPase and 423±14, 670±40, and 721±10 for Mg2+-ATPase as μ mol Pi liberation/min•5g of surimi, respectively. A definite correlation between the grade of surimi and the total activity is evident through this experiment.
The myofibrillar ATPase total activity of surimi was also closely related to the jelly strength of kamaboko from the same material. The Mg2+-ATPase activity was found to be a useful index for evaluating the quality of surimi of grade SA.
