doi: 10.17113/ftb.54.02.16.4166

Preparation, Identification and Antioxidant Properties of Black-Bone Silky Fowl (Gallus gallus domesticus Brisson) Iron(II)-Oligopeptide Chelate

Huanglei Pan^1,2, Shasha Song¹, Qiuyue Ma¹, Hui Wei¹, Difeng Ren^1* and Jun Lu^2*

¹Beijing Key Laboratory of Forest Food Processing and Safety, Department of Food Science and Engineering, College of Biological Sciences and Biotechnology, Beijing Forestry University, 35 Tsinghua East Road, Haidian District, 100083 Beijing, PR China
²Beijing Engineering Research Center of Protein and Functional Peptides, China National Research Institute of Food and Fermentation Industries, 24 Middle Jiuxianqiao Road, Chaoyang District, 100015 Beijing, PR China

Article history:
Received March 12, 2015
Accepted February 15, 2016

Key words:
black-bone silky fowl oligopeptide, chelation, iron(II), structure identification, antioxidant activity, fortified food

Summary:
Black-bone silky fowl iron(II)-oligopeptide chelate was synthesized from iron(II) solution and the black-bone silky fowl oligopeptide, which was extracted from the muscle protein of black-bone silky fowl (Gallus gallus domesticus Brisson). Orthogonal array analysis was used to determine the optimal conditions for the iron(II)-oligopeptide chelate preparation. Ultraviolet-visible (UV-Vis) spectroscopy, electron microscopy, and Fourier transform infrared (FTIR) spectroscopy were used to identify the structure of iron(II)-oligopeptide chelate. 2-Diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging assays were performed to compare the antioxidant abilities of the black-bone silky fowl oligopeptide and iron(II)-oligopeptide chelate. The optimal conditions for iron(II)-oligopeptide chelate preparation were 4 % of the black-bone silky fowl oligopeptide and a ratio of the black-bone silky fowl oligopeptide to FeCl₂·4H₂O of 5:1 at pH=4. Under these conditions, the chelation rate was (84.9±0.2) % (p<0.05), and the chelation yield was (40.3±0.1) % (p<0.05). The structures detected with UV-Vis spectroscopy, electron microscopy and FTIR spectra changed significantly after chelation, suggesting that Fe(II) ions formed coordinate bonds with carboxylate (-RCOO¯) and amino (-NH2) groups in the oligopeptides, confirming that this is a new oligopeptide-iron chelate. The iron(II)-oligopeptide chelate had stronger scavenging activity towards DPPH and superoxide radicals than did the black-bone silky fowl oligopeptide.

*Corresponding author:  rendifeng@bjfu.edu.cn
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