Novel anti-oxidative peptides from enzymatic digestion of human milk

Human milk pepsin and pancreatin digests were separated using molecular membrane and reverse phase chromatography. Chemical screening of the resulting fractions using the ORAC antioxidant assay yielded a peptide fraction (PF-23) with high antioxidant activity (5207 μM Trolox Equivalents (TE)/g). Tandem mass spectrometry allowed the identification of twenty peptides. Eight small molecular weight peptides from 4 to 6 amino acids were synthesised and screened for antioxidant properties using ORAC and linoleic acid emulsion. On ORAC, the peptides YGYTGA (5169 μM TE/mmol) and ISELGW (4479 μM TE/mmol) were the most active. At 250 μM peptide ISELGW and its derivatives significantly reduced hydroperoxides formed during autoxidation of linoleic acid for 4 days at 50 °C. Further testing of these peptides may allow their inclusion in infant formulas to reduce the incidence of oxidative stress-mediated diseases in newborns.