Optimization of the Enzymatic Hydrolysis of Poultry Slaughterhouse Wastes using Alcalase Enzyme for the Preparation of Protein Hydrolysates

Background and objective: Continuous increases in poultry production have led to increases in slaughterhouse wastes and needs for control of these organic matter-rich wastes. Previously, burning and burial methods were used to control the wastes that contaminated the environment and spread diseases. Nowadays, hydrolysis of the waste proteins is an effective way to produce new added-value products and to control wastes. The aim of this study was to achieve optimal conditions for the enzymatic hydrolysis of the industrial wastes from poultry slaughterhouses. Material and methods: To achieve the highest hydrolysis efficiency, an experimental design was used based on the surface response methodology to assess optimum conditions of the hydrolysis reaction parameters. Factors, including temperature (50-70 degrees C), pH (6.5-8.5) and enzyme to substrate ratio (1.5-5.5% (v w(-1))), were investigated at five levels using central composite design. Degree of the hydrolysis was considered as response. Results and conclusion: Statistical analysis showed that the regression coefficient (R-2) for the model included 0.9592, which indicated a high accuracy of the model to predict the reaction conditions with variables. The highest degree of hydrolysis was achieved as 12.78% at an enzyme/substrate ratio of 3.5%, pH of 7.5 and temperature of 60 degrees C. Under optimized conditions, hydrolyzed proteins included molecular weights less than 14.5 kDa. Results have shown that enzymatic hydrolysis of the whole poultry slaughterhouse wastes is possible using alcalase as a protease enzyme.