Isolation of collagen from chicken feet with hydro-extraction method and its physico-chemical characterisation

Chicken slaughterhouses generate a large volume of chicken feet as a waste or by product. Nowadays, the chicken feet have not been optimally utilised. One of the ways to increase added value of the chicken feet is to utilize collagen contained in it. The objectives of this study were to obtain the best treatments in pre-treatment and hydrolysis stages of collagen extraction from chicken feet using hydro-extraction method, and to characterise the physico-chemical properties of the isolated collagen. Collagen extraction consisted of three stages of pre-treatment, hydrolysis, and hydro-extraction. Pre-treatment stage used NaOH concentrations of 0.5, 1, and 2 M, and soaking times of 2, 4, 6, and 8 hours. The hydrolysis used CH₃COOH concentrations of 0.1, 0.3, and 0.5 M, and soaking times of 1, 2, and 3 hours. The best condition of pre-treatment was 0.5 M NaOH concentration with 6 hours of soaking time, while the best condition of hydrolysis was 0.5 M CH₃COOH concentration with 1 hour soaking time. FTIR spectroscopy showed that the isolated collagen amino acids consisted of amide A, amide B, amide I, amide II, and amide III groups. The dominant amino acid contents were glycine, L-serine, L-proline, L-glutamic acid, and L-alanine.