Abstract: Pepsin-soluble collagen was extracted from the scales and skin of Asian seabass, and their physicochemical properties were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), amino acid composition analysis, differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, zeta potential and solubility measurement. The yields of scale collagen and skin collagen were 2.3 and 47.3 g/100 g (dry weight), respectively. The SDS-PAGE profile showed that both collagens contained [α1(I)]2α2(I) and were characterized as type I collagen. DSC indicated that denaturation temperatures (Td) of scale and skin collagen were 37.54 and 36.74 ℃, respectively. Based on FT-IR spectra and X-ray diffraction spectra, after pepsin treatment, the triple-helical structure of the collagens was still intact. Zeta potential studies indicated that scale and skin collagen had a net charge of zero at pH 6.40 and 6.64, respectively. Both collagens exhibited high solubility under acidic and low salt concentration conditions.

Key words: Asian seabass, scale, skin, collagen, amino acid