Abstract
In the previous paper the authors have reported on the nutritional values for rats, amino acid composition and artificial digestibility of extracted Euphausia superba (E. superba) protein concentrate compared with whole egg protein.
In this experiments the authors have investigated with reference to the protease and tyrosinase activity that is presumed to be closely related to autolysis and discoloration of E. superba. Furthermore, myosin ATPase activity was measured by considering with the fish jelly products of E. superba. Sample of E. superba frozen on board immediately after catching was obtained from Antarctic Ocean and frozen fresh prawn and shrimp were used as a control. Protease activity was measured with liberated amino acid by Lowry method. Tyrosinase activity was measured with oxygen up-take using manometer by Keilin Mann method. Myosin ATPase activity was determined with liberated phosphorous by Fiske Subbarow method.
The following results were obtained.
(1) Protease activity of E. superba was recognized to be of much higher against prawn and shrimp protease activity, but optimum pH and temperature of E. superba shrimp protease showed the same values of pH 8.0 and 40°C.
(2) Tyrosinase activity of prawn and shrimp using catechol as substrate showed higher tendency than E. superba tyrosinase activity. And more, optimum pH and temperature of E. superba or shrimp tyrosinase was pH 7.5 and 25°C.
(3) The values of myosin ATPase activity on E. superba was confirmed to be clearly different in comparison to prawn and shrimp myosin ATPase activity. The optimum pH and temperature of E. superba or shrimp myosin ATPase was recognized to be pH 6.0 and 20°C.
