Extraction and characterization of acid- and pepsin-soluble collagens from the scales, skins and swim-bladders of grass carp (Ctenopharyngodon idella)

The objective of this study was to characterize and compare the acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from the scales, skins and swim-bladders of grass carp. Both ASC and PSC from the three tissues were mainly characterized as type I collagen, with similar electrophoretic patterns and amino acid profiles. PSC from the three tissues was more susceptible to hydrolysis by V8 protease than ASC. Both ASC and PSC from the three tissues showed similar peptide hydrolysis patterns. The maximum transition temperatures of both ASC and PSC from the internal tissue (swim-bladders) were only slightly higher than those of ASC and PSC from the external tissues (scales and skins). These results suggest that collagens from the three tissues of grass carp had almost similar biochemical properties, and could be used as potential substitutes for mammalian collagens due to their comparatively high thermostability.