Characterisation of acid soluble collagen from skins of young and adult Nile perch (Lates niloticus)

Acid soluble collagen (ASC) was extracted from the skins of young and adult Nile perch (Lates niloticus) using 0.5 M acetic acid and precipitation with 0.9 M NaCl. The ASC yields, on a dry weight basis, were 63.1 and 58.7%, respectively for young and adult fish skins. SDS-PAGE showed that the collagens contained two alpha components (α1 and α2). ASC from Nile perch was found to contain more imino acids (19.3 and 20.0%, respectively, for young and adult fish) than most fish species. The denaturation temperature for the collagens from the skins of young and adult Nile perch was determined to be 36 °C, which is also higher than that for most other fish species. Fourier transform infrared spectroscopy showed a higher degree of molecular order in ASC from adult than from young Nile perch. The results indicate that age-related changes in Nile perch skin collagen are not very pronounced, probably because there is minimal development of mature cross-links.