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.

Formulation of microencapsulated rutin and evaluation of bioactivity and stability upon in vitro digestive and dialysis conditions.

Rutin, a flavanol, has been demonstrating excellent antioxidant, anti-inflammatory, anti-diabetic, and anti-carcinogenic properties. However, bioavailability is low due to low stability, solubility, digestion, and absorption by the intestine. This study aims to encapsulate rutin with three types of carrier materials using three different techniques and evaluate their antioxidant activity and bioactivity retention under in vitro gastrointestinal and dialysis conditions. Results showed that the rutin encapsulated lipid carrier has the highest radical inhibition activity for all the digestive phases, the highest singlet oxygen scavenging activity after the gastric phase and the highest anti-inflammatory activity for the dialyzable fraction. The rutin content of encapsulated lipid carriers for all the digestive phases was significantly higher (P≤0.05) comparatively. Fourier Transform Infrared spectroscopy, Particle size analysis, and Scanning Electron micrographs showed that rutin encapsulated lipid carrier was 1.7 µm with a polydispersity index of 0.909 indicating micro-encapsulation with heterogeneous dispersion.