Abstract:

To obtain high degree of hydrolysis (DH) and concentration of amino acid nitrogen, we optimized the hydrolysis catalyzed by alkaline protease of ground whole tilapia. The effects of three crucial variables including temperature, pH and hydrolysis time on the hydrolysis were investigated by single-factor method while the effects of dosage of enzyme and protein concentration were analyzed by response surface methodology (RSM) where the interaction between the two factors was also considered. Under the optimized conditions including dosage of alkaline protease 23740 U/g protein, protein concentration 2.76%, 55 ℃, pH 7.5 for a hydrolysis of 8 h, a concentration of amino acid nitrogen of 1.43 mg/ml and a DH of 33.35% were achieved, and the total volatile basic nitrogen reached 0.034 mg/ml.

Key words: tilapia, alkaline protease, hydrolysis, optimization