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Proteomics to better define wheat gluten peptides

Proteomics to better define wheat gluten peptides
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May 17 2017

JRC scientists identified a set of unique wheat-gluten peptides, proposed as wheat specific markers, using a comprehensive proteomic approach. These markers will support the quantification of gluten in food products, ensuring more reliable food labelling and better protection for consumers with gluten intolerance.

Gluten is a generic term given to a mixture of proteins found in wheat, rye, barley and oat. The labelling of "gluten-free" and "very low gluten" food products specifically targeted towards individuals who wish to control their intake of gluten is regulated in the EU. The current requirement for labelling a product as "gluten-free" sets a maximum permissible amount of 20 mg of gluten per kg of food. Current production processes including: crop rotation; the use of shared transport and processing facilities; the use of cereal flours as carriers or thickening agents, can results in a low level presence of gluten in otherwise naturally gluten-free products. Therefore, a precautionary approach, requiring the measurement of the gluten content in the final product, is taken by many specialist food producers.

The measurement of gluten is complex. The number and sequence variations of its constituent proteins, due to different plant species and their many varieties, cause major issues for the current testing technologies. This has resulted in a lack of comparability of measurement results from different laboratories.

JRC scientists have investigated a multi enzyme digestion method followed by mass spectrometry detection for monitoring multiple sequence specific peptides from wheat gluten. A set of marker peptides were identified as: being specific to wheat, unique to a single gluten protein; known to contain immunogenic or toxic sequences to those suffering with coeliac disease. The approach can be applied to identify markers from other gluten sources and their future quantification should result in a more accurate and robust estimation of the gluten content of gluten free food.

Read more in: M.J. Martinez-Esteso et al "Defining the wheat gluten peptide fingerprint via a discovery and targeted proteomics approach", Journal of Proteomics 147 (2016) 156–168, doi:10.1016/j.jprot.2016.03.015