Oat of this world: Defining peptide markers for detection of oats in processed food

People affected by Coeliac disease rely on the purity and accurate labeling of food products in order to follow a strict gluten-free diet, the only treatment for Coeliac disease. The safety of oats in the gluten-free diet remains controversial because they contain the gluten-like avenins. In the present study, global proteomic analyses were performed via LC-MS/MS on gluten-enriched fractions extracted from 22 diverse oat cultivars. A panel of oat peptides was assessed using multiplereaction monitoring mass spectrometry to define peptide markers that were unique to oats but were present in all 22 oat cultivars. The method was successfully applied to: (1) the detection of oat contamination in spelt, rice, rye, and buckwheat flours; and (2) the analysis of 7 highly processed commercial food products. The oat peptide markers were detected at high levels in a breakfast cereal and a muesli where oats were a named ingredient, but the presence of oats was also noted in 3 of the 5 breakfast cereals where oats were not named as an ingredient. LC-MS/MS represents a rapid, sensitive, robust and reproducible method for detecting oat contamination in both processed and unprocessed foods.