Preparation of phosphopeptide-iron chelates from Mylopharyngodon piceus roe phosvitin using high voltage pulsed electric field pretreatment combined with enzymolysis

Peptide–iron chelates were prepared, and their chelating properties were explored. High voltage pulsed electric field (PEF) was used to assist in the extraction of phosvitin (Pv) from Mylopharyngodon piceus roe, and the Pv extract was subsequently treated and enzymolyzed to obtain phosphopeptide (PP). After PEF pretreatment and enzymatic hydrolysis, total antioxidant capacity and Fe 2 ⁺-chelating ability of PP increased by 54.45% and 12.06%, respectively. Peptide–iron chelates (PP 8 -Fe) were prepared using PP with the highest antioxidant activity. Chelate structure determination revealed that PP 8 -Fe was rich in amino acids with strong metal ion chelation capabilities, namely Glu, Asp, and Ser, which accounted for 50.91% of the total amino acids. Compared to PP 8 , PP 8 -Fe exhibited a more loosely structured surface at the microstructural level, increased iron content, a shift in secondary structure from random coil to α-helix and β-sheet, an increase in weighted average particle size from 420.20 ± 2.80 nm to 768.50 ± 1.90 nm, an increase in zeta potential from -33.70 ± 0.60 mV to -3.78 ± 0.46 mV, enhanced hydrophobicity, an increase in ΔH, and good gastrointestinal digestion stability. PP 8 has iron chelating sites, including phosphate, carboxyl, carbonyl, amino groups, and sialic acid residues. Our findings provide a theoretical foundation for peptide preparation and enhancement of their bioactivity via PEF pretreatment, while also providing guidance for future research on their chelation mechanisms with metal ions.