Development and Validation of the Detection Method for Wheat and Barley Glutens Using Mass Spectrometry in Processed Foods

Currently, the only effective treatment for coeliac disease is a gluten-free (GF) diet to avoid gluten-containing food intake. However, the current enzyme-linked immunosorbent assay (ELISA) method for detecting gluten lacks the ability to precisely detect and quantify gluten in fermented and hydrolyzed foods. The purpose of this study was to use liquid chromatography-tandem mass spectrometry (LC-MS/MS) to develop a robust and stable method for gliadin and hordein detection when assessing food safety. This study successfully extracted hordein from barley flour to use as a reference standard. Liquid chromatography/quadrupole time-of-flight mass spectrometer (LC/Q-TOF/MS) performed an analysis to identify unique marker peptides from gliadin and hordein. For determining the limit of detection of gluten in GF products, gliadin and hordein were spiked into GF products at concentrations of 1–100 mg/kg with isotope-labeled peptides as internal standards (IS). The developed method enabled the detection of 2.5 mg/kg of wheat and barley gluten in GF products. Finally, compared with the immunochemical method, the ability for the MS-based method to detect and quantify gluten content from fermented and hydrolyzed foods was unaffected and demonstrated the potential to analyze suspected gluten-contaminated foods to assess product safety.