Peptidomics of an industrial gluten-free barley malt beer and its non-gluten-free counterpart: Characterisation and immunogenicity

Food Chem. 2021 Sep 1:355:129597. doi: 10.1016/j.foodchem.2021.129597. Epub 2021 Mar 18.


Recent research suggests that gluten-free beers by prolyl-endopeptidase treatment may not be safe for coeliac disease (CD) patients. Therefore, the gluten peptidome of an industrial gluten-free prolyl-endopeptidase treated malt beer (<10 ppm gluten) was compared to its untreated counterpart (58 ppm gluten) as a reference. NanoLC-HRMS analysis revealed the presence of 155 and 158 gluten peptides in the treated and reference beer, respectively. Characterisation of the peptides in treated beer showed that prolyl-endopeptidase activity was not complete with many peptides containing (multiple) internal proline-residues. Yet, prolyl-endopeptidase treatment did eliminate complete CD-immunogenic motifs, however, 18 peptides still contained partial, and potentially unsafe, motifs. In the reference beer respectively 7 and 37 gluten peptides carried (multiple) complete and/or partial CD-immunogenic motifs. Worrying is that many of these partial immunogenic gluten peptides do not contain a recognition epitope for the R5-antibody and would be overlooked in the current ELISA analysis for gluten quantification.

Keywords: Gluten peptidome; Gluten-free malt beer; Hordein peptides; Immunogenic peptides; NanoLC-HRMS; R5-cELISA epitope.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Beer / analysis*
  • Celiac Disease / immunology
  • Celiac Disease / pathology
  • Chromatography, High Pressure Liquid
  • Glutens / analysis*
  • Glutens / immunology
  • Glutens / metabolism
  • Hordeum / immunology
  • Hordeum / metabolism*
  • Humans
  • Mass Spectrometry
  • Nanotechnology
  • Peptides / analysis
  • Peptides / immunology
  • Prolyl Oligopeptidases / metabolism
  • Proteomics / methods*


  • Peptides
  • Glutens
  • Prolyl Oligopeptidases