• Collagen hydrolysate from parrot fish (Scarus ghobban) skin: extraction and characterization of secondary structure for biomaterials and bioscaffolds
  • Rezvan Mousavi-Nadushan,1,* Naghmeh Roohi-Shalmaee,2 Shima Abasi,3
    1. Department of Marine Science, Faculty of Natural Resources and Environment, Tehran North Branch, Islamic Azad University, Tehran, Iran.
    2. Venom and Biotherapeutics Molecules Lab., Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran. Tehran, Iran.
    3. Department of food science and technology, North Tehran Branch, Islamic Azad University, Tehran, Iran


  • Introduction: The consumption of various fish species, including Scarus ghobban, in Iran is gradually increasing. Iranian consumers have become more conscious for the profits of eating fish and consuming fish of high quality, like parrotfish, for its high Fatty acid values, a high content of essential metals and a low quantity of heavy and non‐essential metals. Collagen is one of the most important compound in the connective tissue which is widely used as biomaterial in medicine and cosmetic industry. In addition, recent research has demonstrated the functional, beneficial, and potential properties of collagen extracted from aquatic wastes as biomaterials, tissue engineering and for delivery systems of sensitive bioactive compounds. Fourier transform infrared (FTIR) spectroscopy has been used to study changes in the secondary structure of collagen, collagen hydrolysate, structural crosslinking and denaturation. The spectral variations which are indicative of deviations in collagen secondary structure have been revealed to include variations in the amide I (1636–1661 cm_1), amide II (1549–1558 cm_1) and the amide III (1200–1300 cm_1) regions. Fibrillogenesis (self-assembly) of collagen has been found to be associated with broadening and a minor alteration to lower wave number of the amide A peak, increase in intensity and minor transfer to lower wave number of amide III, band extending and alteration of amide I to lower wave number and alteration of amide II to lower wave number. Alternatively, the absorption proportions between amide III and the peak of C-H bending vibration validate the prevalence of a helical structure. This study was aimed to investigate structural character of Acid-soluble collagen (ASC), and Hydrolyzed collagen extracted from the skin of parrotfish (Scarus ghobban).
  • Methods: Extraction: The collagen of the parrotfish (Scarus ghobban) skin was extracted by acid acetic and enzymatic methods. Crude collagen was extracted using 0.5 M acetic acid solution (1:20 w/v) after defatting and eliminating the non-collagenous proteins. Collagen hydrolysate were produced by pepsin (2500–3500 U/mg protein), with an enzyme/collagen ratio of 1:20 (w/w) from extracted ASC. FTIR: the extracted collagen and collagen hydrolysate was investigated by Fourier-transform infrared (FTIR) spectroscopy.
  • Results: FTIR Spectroscopy spectra for collagen and collagen hydrolysate extracted from skin of parrotfish Infrared (IR) spectra of collagen hydrolysate extracted from parrotfish skin showed the typical characters for type I collagen, including five peaks amide A (at 3287.89 cm-1), amide I (at 1667.35 cm-1), amide II ( at 1552.35 cm-1) and amide III (at 1243.53 cm−1 ) in the spectrogram. But just the absorption band characteristic of amide II was very similar for acid soluble collagen, arising at 3221.12 Cm-1 correspondent to amide A, and 1653.37 Cm-1 correspondent to NH bending vibration of amide II.
  • Conclusion: Amide A bands of parrotfish skin ASC collagen and collagen hydrolysate were found at 3287, and 3221.12 Cm-1 -1, respectively. A shift of the amide A to lower number in this group may indicate that N-H bonds are involved in a slightly different hydrogen bond network and Fibrillogenesis (self-assembly) of ASC collagen. The spectra of parrotfish skin collagen hydrolysate revealed a characteristic pattern reflecting the amide I band at 1667.35 cm-1, the amide II band at 1552.35 cm-1, and amide III band at 1243.53 cm-1, derived from C=O stretching, N–H bending vibrations, and C– H stretching, respectively. Amide III also represented the combination peaks between C-N stretching vibrations and N-H deformation from amide bonds as well as absorptions arising from waving vibrations from CH2 assemblies of the glycine backbone and proline side-chains. The absorption band characteristic of amide II was very similar for acid soluble collagen and collagen hydrolysate, arising at 1552.35 cm-1, which associated with NH bending vibration couplet with CN stretching. On the other hand the absorption proportion between amide III and the 1452.32 cm-1 band was close to 1.0 in the spectrogram of collagen hydrolysate from parrot fish skin, and the result designates the attendance of triple-helical structure. Moreover, FTIR analysis indicated some differences in the construction of collagen and collagen hydrolysate. The knowledge about their secondary structures gives possibility to modify chemical and enzymatic methods. So Collagen and collagen hydrolysate of parrotfish represented structural diversity and self-assembling complexity and could be a promising biomaterial for regenerative medicine applications.
  • Keywords: biomaterial, collagen, collagen hydrolysate, parrotfish (Scarus ghobban)