Novel insights into whey protein peptide-iron chelating agents: Structural characterization, in vitro stability and functional properties

Abstract

In this study, whey protein iron chelating peptides were obtained by trypsin hydrolysis of whey protein, and the whey protein peptides-iron chelate (WPP-Fe) was prepared. The structural characterization of the whey protein peptides-iron chelate were determined, comprising ultraviolet-visible spectrum, fluorescence spectrum, infrared spectrum, secondary structure content, x-ray diffraction, particle size, zeta potential, microstructure and surface elemental compositions. The results showed that under the conditions of pH 5.0, the mass ratio of whey protein peptides to FeSO4 was 3:1, chelated at 35 °C for 30 min, iron chelating and chelating yield was 85.92% and 77.38% respectively. The content of aspartic acid and glutamic acid were positively correlated with iron chelating ability. The whey protein peptides-iron chelate had good pH, salt concentration and gastrointestinal digestive stability compared to FeCl2, ferrous gluconate and ferrous glycine. Besides, the DPPH eliminate ability and bacteriostatic properties of the whey protein peptides-iron chelate (WPP-Fe) were better than the whey protein peptide (WPP). These findings can be used as a theoretical basis for the development of new peptide iron supplements.