High Temperature Cooking of Fish Protein Extracts for Plastein Reaction

High Temperature-cooking conditions of cultured fishes(loach, crucian carp, bastard halibut, and jacopever) were optimized by response surface methodology(RSM), and plastein products were prepared using enzymatic hydrolysis. Four models were proposed with regard to effects of time(t), temperature(T), and water/fish meat (w/f) ratio on the amount of 0.3M TCA soluble fractions. The model coefficients were ranged from p<0.0001 for jacopever to p<0.0433 for bastared halibut. Cooking conditions for 60% hydrolysis were optimized at 1) 14$0^{\circ}C$ except for crucian carp(136$^{\circ}C$); 2) 10.08 hours(loach), 7.25 hours(crucian carp), 9.85 hours(ba-stard harlibut), and 9.37 hours(iacopever); 3) 1:1(w/f) ratio except for the crucian carp(1.1:1). When protein hydrolyzates were employed for the plastein synthesis, optimum plastein-reaction conditions were determined to be pH 9.0 with chymotrypsin for the loach and crucian carp hydrolyzates, pH 9.0 with papain for the bastard halibut hydrolyzate, and pH 11.0 with trypsin for the jacopever hydrolyzate. Plastein reaction could be performed in water at concentration up to 20%(w/f).