Extraction and characterisation of type I collagen from the skin offcuts generated at the commercial fish processing centres

Effective use of underutilised fish processing by-products could open avenues for new industries if they are used to extract high-valued bioactive compounds. Therefore, discarded skin offcuts of three main commercial fish species of Sri Lanka were used to extract collagen with acetic acid and the extracted collagen was evaluated for industrial suitability. The yields of acid-soluble collagens from Yellowfin tuna (Thunnus albacares), Seer fish (Scomberomorus commerson) and Asian sea bass (Lates calcarifer) were 61.26%, 58.21% and 59.31%, respectively on a dry-weight basis. Fourier Transform Infra-Red spectra and X-ray Diffraction spectra confirmed that all collagens were in type I and preserved the native triple-helical structure during extraction. The UV absorption spectra confirmed a high collagen purity in all species. These results confirm that the extracted collagen consists of the characteristics required for collagen-based industries such as food, pharmaceutical, and biomedical. The high availability of skin offcuts from the processing industry and the higher collagen yields revealed in this study confirm the possibility of using discarded skin offcuts of the three fish species as a potential source of type I collagen for industrial purposes.