Quantification of Barley Contaminants in Gluten-Free Oats by Four Gluten ELISA Kits

Xin Huang, Hanna Gabriela Ahola, Matthew Daly, Chiara Nitride, Clare Mills, Tuula Sontag-Strohm

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Pure oats are generally accepted to be safe for most celiac patients, and consumption of oats provides advantageous dietary fibers. However, oats can be contaminated by gluten proteins from wheat, barley, and/or rye. The analytical challenge lies in the reliability of the quantification method and how to maintain the contamination level under a gluten-free food threshold of 20 mg/kg. In this study, we investigated barley-spiked oat flour samples at four levels using four gluten ELISA kits. The largest recovery variance was with the R5 kit that gave 5-6 times overestimation; the G12 kit cross-reacted with oat proteins and gave 4-5 times overestimation at all spiked levels. The Total Gluten and Morinaga kits gave satisfactory recoveries. Total barley hordeins were isolated and characterized to be used as a common calibrator in all four kits aiming at harmonizing the results and to test the kits' performance. Immunoblotting of total hordein isolate revealed that Total Gluten and Morinaga antibodies provided an overall detection, while R5 and G12 antibodies recognized specific hordein groups leading to a larger difference when wheat and barley were used as the calibrant. Calibration with total hordein isolate corrected the overestimation problem and decreased the variability between the four gluten kits.

Original languageEnglish
JournalJournal of Agricultural and Food Chemistry
Volume70
Issue number7
Pages (from-to)2366–2373
Number of pages8
ISSN0021-8561
DOIs
Publication statusPublished - 23 Feb 2022
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 416 Food Science
  • 3143 Nutrition
  • codex
  • celiac disease
  • R5
  • G12
  • overestimation
  • calibrator
  • reference material
  • WHEAT
  • HORDEIN
  • DIET
  • RYE

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