Background and Objectives: Collagen is a protein with several applications in the pharmaceutical, cosmetic, medical and food industries that is prepared from different sources such as cow, pig, poultry and fish. In this study, optimization of the extraction of collagen from eggshell membrane was examined.

Materials and Methods: The efficiency of extraction of collagen in different concentrations of sodium hydroxide (2/0-2 /1 N) at different treatment times periods (6-36 hours), different concentrations of pepsin (U/mg90-15) and enzymatic hydrolysis times (6-60 hours) was studied with response surface methodology (RSM). Also the properties of eggshell membrane collagen were characterized by amino acid analyzer, SDS- PAGE and solubility.

Results: The most important factors for extraction of collagen using RSM according to central composite design were optimized. Optimum extraction conditions were as follows: NaOH concentration of 0.76 N, alkali treatment time of 18 h, enzyme concentration of 50 U/mg and hydrolysis time of 43.42 h. The experimental extraction yield under optimal conditions was found to be 30.049%. Collagen solubility in pH=3 and NaCl concentration of less than 2% was determined. The analysis showed that Glycine having 322/1000 amino acids as the most amino acids and the immune-acid (sum of Proline and hydroxylproline) of collagen was 19.5 %. SDS- PAGE protein pattern revealed two different a (α1 and α2) components with β and γ chains.

Conclusion: Collagen was extracted from eggshell membrane with optimum extraction efficiency, which can be used in film production, gelatin and functional food components to maintain health and control chronic diseases.

Keywords: Extraction, Collagen, Response surface methodology, Physicochemical characteristics