Optimization of the production of protein hydrolysates from meat industry by products by response surface methodology

In the present study, response surface methodology was used to optimize hydrolysis conditions of protein hydrolysate from the sheep visceral (stomach, intestine), using Alcalase 2.4l. The investigated factors were temperature (43-52°C), time (65-190 min) and enzyme/substrate ratio (50-95 AU/Kg protein) to achieve maximum degree of hydrolysis and recovery of nitrogen. Experiments were designed according to the central composite design. Each of the studied variables had a significant effect on responses (p<0/01). The optimal conditions to achieve the highest degree of hydrolysis and recovery of nitrogenwere, temperature (47.17, 47.56°C), time (158.74, 153.38 min), and enzyme/ substrate ratio (78.60, 76.03 AU/Kg protein), respectively. Under these conditions, hydrolysis degree, nitrogen recovery were 36.3%, 72.67%, respectively. Regression coefficient for each of the models (Quadratic type) for degree of hydrolysis, recovery of nitrogen were, 0.988, 0.986, respectively. The values indicated the high accuracy of the model to predict the reaction conditions considering different variables. The chemical analysis of protein hydrolysate showed high protein content (83.78%) and low fat content (0.34%).