Extraction and characterization of acid-soluble collagen from scales and skin of tilapia (Oreochromis niloticus)

•ASCs were extracted from the scales and skin of tilapia.•SKC showed the higher yield than SCC.•SCC exhibited higher thermal stability than SKC.

Acid-soluble collagen (ASC) was extracted from scales and skin of tilapia. The yields of scale collagen (SCC) and skin collagen (SKC) were 3.2 g/100 g and 27.2 g/100 g respectively, dry weight. The SDS-PAGE profile showed all collagen samples contained [α1(I)]2α2(I) component and were characterized as type I collagen. LC-MS/MS analysis confirmed the SCC and SKC to be Oreochromis niloticus type I collagen. Amino acid analysis revealed the imino acid content from the SCC and SKC samples were 207 and 197 residues/1000 amino acid residues, respectively. Based on FTIR spectra and X-ray diffraction, isolation of ASC did not affect its three dimensional structure. Zeta potential studies indicated both SCC and SKC exhibited a net zero charge at pH 6.82 and 6.42, respectively. Both ASC samples exhibited high solubility in acidic pH (1-3) and lost their solubility at NaCl concentrations below 3 g/100 mL. The data collected here indicate that SCC and SKC may be suitable for use as an alternative to land-based mammalian collagen in food, nutraceuticals and pharmaceutical industries.