Identification of short peptide sequences in the nanofiltration permeate of a bioactive whey protein hydrolysate

Solène Le Maux, Alice B. Nongonierma, Brian Murray, Phil M. Kelly, Richard J. FitzGerald

Research output: Contribution to journalArticlepeer-review

Abstract

Short peptides in food protein hydrolysates are of significant interest as they may be highly bioactive whilst also being bioavailable. A dipeptidyl peptidase IV (DPP-IV) inhibitory whey protein hydrolysate (WPH) was fractionated using nanofiltration (NF) with a 200Da MWCO membrane. The DPP-IV half maximal inhibitory concentration of the NF permeate (IC50=0.66±0.08mgprotein equivalentmL-1) was significantly more potent (P>0.05) than that of the starting WPH (IC50=0.94±0.24mgprotein equivalentmL-1) and associated retentate (IC50=0.82±0.13mgprotein equivalentmL-1). This confirmed the contribution of short peptides within the NF permeate to the overall DPP-IV inhibitory activity. An hydrophilic interaction liquid chromatography (HILIC-) and reverse-phase (RP-) liquid chromatography tandem mass spectrometry (LC-MS/MS) strategy, based on two retention time models, allowed detection of eight free amino acids and eight di- to tetrapeptides in the NF permeate. The potential sequences of the peptides within the NF permeate were then ranked on the basis of their highest probability of occurrence. A confirmatory study with synthetic peptides showed that valine-alanine (VA), valine-leucine (VL), tryptophan-leucine (WL) and tryptophan-isoleucine (WI) displayed DPP-IV IC50 values <170μM. The NF and LC-MS strategies employed herein represent a new approach for the targeted identification of short peptides within bioactive food protein hydrolysates.

Original languageEnglish
Pages (from-to)534-539
Number of pages6
JournalFood Research International
Volume77
DOIs
Publication statusPublished - 1 Nov 2015

Keywords

  • Bioactive peptides
  • Dipeptidyl peptidase IV inhibition
  • Mass spectrometry
  • Retention time
  • Short peptides

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