Two-step Enzymolysis Technology of Hard Clam (Meretrix meretrix L.) Meat with Compound Proteases

Hard clam meat was firstly hydrolyzed with combined neutral protease and trypsin, and then hydrolyzed with Flavourzyme. The combined ratio of neutral proteinase and trypsin was determined by q-test, and the hydrolysis parameters of Flavourzyme were optimized by orthogonal test in terms of hydrolysis yield and total amino nitrogen content. Meanwhile, the superiority of this enzymolysis technology (defined as technology III) was confirmed by measuring degree of hydrolysis (DH) and hydrolysis yield and analyzing amino acid composition of hydrolysate, compared with first neutral protease hydrolysis and then Flavourzyme hydrolysis (technology I), first trypsin hydrolysis and then Flavourzyme hydrolysis (technology II) and first trypsin hydrolysis and then neutral protease hydrolysis (technology IV). Results showed that the optimal combined ratio of t neutral proteinase and trypsin was 3:1, and the optimum hydrolysis conditions of Flavourzyme were as follows: enzyme dosage 1000 U/g raw material, hydrolysis temperature 55 ℃, time 5.0 h, and pH 5.00 ± 0.05. Under the above conditions, the degree of hydrolysis, hydrolysis yield and flavor score were 55.97%, 87.14% and 230.98, respectively.