The increased production of broiler chickens has resulted in a great amount of by-products, which are generated during the slaughter process. Currently, food and pharmaceutical industries express great interest in the research and application of various methods focus on the utilization of by-products. In this context, the objective of this research was to select the proteolytic enzyme of better activity and a hydrolytic process to obtain peptides using a mixture of chicken comb and wattle (1: 1 w / w), using Full Factorial Planning, Response Surface and Desirability function. Initially, the hydrolytic activities of the enzymes [Alcalase (Bacillus licheniformis), Flavourzyme (Aspergillus oryzae), Protamex (Bacillus licheniformis and Bacillus amyloliquefaciens), Brauzyn (Carica papaya) and Colagenase (Clostridium histolyticum)] were evaluated. The optimal pH and temperature of each enzyme were indicated by the manufacturers. The enzyme to substrate ratio (5%) and the total hydrolysis time (240 minutes). The conditions of protease mediated hydrolysis of the chicken combs and wattles were optimized via a 22 Full Factorial Planning, which consisted of 4 factorial points and 3 central points for 7 experiments in total. The independent variables investigated were E:S (enzyme/substrate ratio) and T (hydrolysis time in minutes). The response function was measured as the percentage of the degree of hydrolysis (% DH).
The enzyme Alcalase presented the highest degree of hydrolysis (DH = 19%) in comparison to the other proteases (DH <3%). After selection of the enzyme, the hydrolysis process was optimized. By means of the evaluation of the Response Surface and Desirability Function, the experiment that showed the highest degree of hydrolysis was selected; i.e. enzyme/substrate ratio of 5% and 240 minutes of hydrolysis, with a DH of 19%.