title: Triple helical structure of acid-soluble collagen derived from Nile tilapia skin as affected by extraction temperature.
abstract: BACKGROUND
  Fish skin has become a new source of collagen. It is usually extracted at low temperature. Increasing the extraction temperature can increase the collagen yield. However, high temperature might cause degradation of the triple helical structure of collagen, which is related to its functional biomaterial. This work thus aimed to investigate the effect of extraction temperature on the extraction efficiency and characteristics of acid-soluble collagen (ASC), particularly its triple helical structure.
  
  
  RESULTS
  ASC was extracted at 5 ± 1, 15 ± 1 and 25 ± 1 °C for 0-24 h with 0.3 or 0.5 mol L(-1) acetic acid. The results showed that extraction with 0.5 mol L(-1) acetic acid gave a higher extraction efficiency than that in 0.3 mol L(-1) acetic acid (P < 0.5). Extraction at 25 ± 1 °C for 5 h with 0.5 mol L(-1) acetic acid gave a higher extraction efficiency (73.73 ± 1.28%), which is higher than that of 5 ± 1 °C by about 1.7-fold. All ASC obtained were identified as type I collagen and showed similar physicochemical properties.
  
  
  CONCLUSIONS
  The results showed that extraction temperature strongly affected extraction efficiency. Extraction at 25 °C did not affect the triple helical structure, which was confirmed by the results of Fourier transform infrared, circular dichroism spectrum and collagen self-assembly. © 2015 Society of Chemical Industry.
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, Thailand.|Membrane Science and Technology Research Center, Prince of Songkla University, Songkla University, Songkhla, Thailand.
authors.forename: Mantaka
authors.initials: M
authors.lastname: Thuanthong
authors.affiliation: Nutraceutical and Functional Foods Research and Development Center, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Nualpun
authors.initials: N
authors.lastname: Sirinupong
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, Thailand.|Membrane Science and Technology Research Center, Prince of Songkla University, Songkla University, Songkhla, Thailand.
authors.forename: Wirote
authors.initials: W
authors.lastname: Youravong
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000818:Animals; D023681:Cichlids; D002942:Circular Dichroism; D003080:Cold Temperature; D024042:Collagen Type I / Q000737:chemistry* / Q000191:economics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D029941:Fish Proteins / Q000737:chemistry* / Q000191:economics / Q000302:isolation & purification; D005525:Food-Processing Industry / Q000191:economics; D006909:Hydroxyproline / Q000032:analysis; D007202:Indicators and Reagents / Q000737:chemistry; D007220:Industrial Waste / Q000032:analysis* / Q000191:economics; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D011489:Protein Denaturation; D017510:Protein Folding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D012867:Skin / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013785:Thailand
chemical_list: D024042:Collagen Type I; D029941:Fish Proteins; D007202:Indicators and Reagents; D007220:Industrial Waste; D019342:Acetic Acid; D006909:Hydroxyproline
keywords: acid-soluble collagen; self-assembly; triple helical structure