Interaction study between wheat-derived peptides and procyanidin B3 by mass spectrometry

Tannins have the ability to complex and precipitate proteins, being particularly reactive towards the proline-rich ones. The main structural feature of the wheat peptides responsible for the onset of Celiac Disease (CD) is their high content in proline residues. The aim of this work was to characterize the binding between a common food tannin (procyanidin B3) and different wheat-derived peptidic fractions. For this, seven peptide mixtures were obtained after in vitro digestion of a wheat gliadins crude extract and further characterized by LC-ESI-MS/MS. Several soluble B3-peptide complexes were identified by ESI-MS. The peptides involved in complex formation varied in terms of their size and diversity in CD epitopes. Although binding selectivity of procyanidin B3 towards peptides containing CD epitopes was not found, the major complexes contained or could contain immunoreactive peptides. This study highlights the potential beneficial effects of food polyphenols as a nutritional approach in the modulation of CD.