Preparation, characterization, and bioavailability evaluation of antioxidant phosvitin peptide‐ferrous complex

Abstract BACKGROUND Iron deficiency anemia (IDA) is one of the commonest global nutritional deficiency diseases, and the low bioavailability of iron is a key contributing factor. The peptide‐iron complex could be used as a novel iron supplement to improve iron bioavailability. RESULTS In this study, antioxidant low molecular weight (<3 kDa) phosvitin peptide (named PP‐4) was separated to prepare a phosvitin peptide‐ferrous complex (named PP‐4‐Fe); then the structural conformation of PP‐4‐Fe was characterized and its bioavailability by in vitro digestion was evaluated. The results showed that PP‐4 had good ferrous‐binding activity with 96.14 ± 2.86 μg Fe 2+ mg −1 , and had a strong antioxidant effect with 995.61 ± 79.75 μmol TE mg −1 in 2,2'‐azinobis'3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) and 62.3 ± 3.95 μmol FeSO 4 mg −1 in ferric ion reducing antioxidant power (FRAP). After ferrous binding, the FRAP activity of PP‐4‐Fe, enhanced by 1.8 times, formed a more ordered structure with an increase in α ‐helix and decrease in γ ‐random coil. The ferrous binding sites of PP‐4 involved were the amino, carboxyl, imidazole, and phosphate groups. The PP‐4‐Fe complex displayed excellent gastrointestinal stability and antioxidant effects during digestion. The iron dialysis percentage of PP‐4‐Fe was 74.59% ± 0.68%, and increased to 81.10% ± 0.89% with the addition of 0.25 times vitamin C (VC). This indicated that PP‐4‐Fe displayed excellent bioavailability and VC in sufficient quantities had a synergistic effect on improving bioavailability. CONCLUSIONS This study demonstrated that antioxidant phosvitin peptide was an efficient delivery system to protect ferrous ions and suggested that the phosvitin peptide‐ferrous complex has strong potential as a ferrous supplement. © 2023 Society of Chemical Industry.