Acid-soluble and pepsin-soluble collagens from grass carp (Ctenopharyngodon idella) skin: a comparative study on physicochemical properties

摘要

In this study, acid-soluble (ASC) and pepsin-soluble (PSC) collagens with triple helical structures were successfully extracted from the skin of grass carp (Ctenopharyngodon idella) by two different extraction approaches. SDS-PAGE pattern revealed that ASC and PSC are type Ⅰ collagens with typical α1, α2 and β-chains. In addition, the intensity of χ-chain (trimer) in ASC was higher than that of PSC, representing the presence of the high proportion of intra- and intermolecular cross-links of extracted collagens with large molecular weight using the acid method. Differential scanning calorimetry (DSC) results demonstrate that T_d (69.04 ℃) of ASC was higher than T_d (62.20 ℃) of PSC. Both ASC and PSC had the highest solubility at acidic pHs or at a low concentration of NaCl (＜2%, w/v). The results of FTIR suggested the ASC and PSC maintained in the helical secondary structure at high degree.