Extraction and characterization of pepsin-solubilized collagen from snakehead (Channa argus) skin: Effects of hydrogen peroxide pretreatments and pepsin hydrolysis strategies

Abstract

Abstract The effects of hydrogen peroxide (H2O2) pretreatments and pepsin hydrolysis strategies on the extraction of pepsin-solubilized collagen (PSC) from the skin of snakehead (Channa argus) were studied. The dependences of H2O2 bleaching on H2O2 concentrations (1%, 3%, and 6% (w/v)) and pH (6, 8, and 10) were examined, while the difference between the conventional and unconventional pepsin hydrolysis methods was compared. Results showed that the yield of snakehead skin PSC was highly dependent on the parameters of both H2O2 pretreatments and pepsin hydrolysis processes. The color of PSC was affected by pH more greatly than by H2O2 concentration. Compared with the conventional pepsin hydrolysis of fish skins, the use of pepsin after extraction of acid-solubilized collagen (ASC) could improve the color of PSC. Moreover, the electrophoretic study, infrared spectroscopy, and fibril formation measurement showed that the structural integrity of PSC was largely influenced by the pH of H2O2 pretreatments, suggesting that the H2O2 solution (3% (w/v), pH 10) was suitable for the bleaching of snakehead skins. Finally, the amino acid analysis, ultraviolet spectroscopy, and differential scanning calorimetry confirmed that the prepared collagen had high purity and thermal stability. The light-color collagen might be used as an alternative for mammalian collagens.