Preparation and characterization of desalted duck egg white peptide-ferrous chelate

In this paper, desalted duck egg white peptides and Fe Cl₂·4H₂O was used as the raw material.Using chelating rate of ferrous and the yield of chelate as trace indexs, the preparation conditions of duck egg peptides-ferrous chelate were optimized, and the structure of peptides-ferrous chelate was characterized by IR, dynamic light scattering, fluorescence spectroscopy and circular dichroism.The results of single factor and orthogonal test showed that the optimal chelating reaction condition of duck egg white peptides-ferrous chelate was as follows: the mass ratio of VCto ferrous salt was 0.2∶ 1, the concentration of duck egg peptides was 4%, the ratio of peptides to ferrous salt was 3 ∶ 1, the p H value was 5.5, the temperature was 40 ℃, the reaction time was 40 min, and the amount of ethanol was 7 times of the volume of the reaction solution. Under these conditions, the chelating rate of ferrous was 65.15%, and the yield of the chelate was 44.46%.The Infrared spectrum showed that Fe²⁺ binds to the amino terminus and the carboxyl terminal of peptide.The fluorescence spectrum showed that the fluorescence absorption band decreased from 3822 nm to 3124.44 nm with the increase of Fe²⁺ ( p < 0.05) .The laser particle size analyzer showed that the radius of peptide and peptide-ferrous chelate was ( 144.23 ± 5.86) nm and ( 453.66 ± 8.74) nm respectively.The circular dichroism showed that the content of α-helix in the peptide was 28.66% ± 1.54% and 10.02% ± 1.04%, while the content ofα-helix and β-sheet in peptide-ferrous chelate was 16.10% ± 1.96% and 27.33% ± 1.08%, both of which had changed significantly ( p < 0.05) .The formation of peptides-ferrous chelate was confirmed from the structural.