Purpose: To develop a competitive ELISA for the detection and characterization of gluten in fermented and hydrolyzed foods.
Methods: A novel competitive ELISA was developed utilizing five gluten-specific antibodies (G12, R5, 2D4, MIoBS, and Skerritt) employed in nine established commercial ELISA test kits that are routinely used for gluten detection. The assay was used to evaluate 20 wheat beers, 20 barley beers, 5 barley beers processed to reduce gluten, 15 soy sauces, 6 teriyaki sauces, 6 Worcestershire sauces, 5 vinegars, and 8 sourdough breads.
Results: The developed ELISA simultaneously measures gliadin, deamidated gliadin, and glutenin specific epitopes present in gluten. Standard curves were generated with a dynamic range of 2.5 to 100 ppm gluten. Cluster analysis of the data generated by the antibodies in the novel competitive ELISA was able to distinguish between the different categories of fermented and hydrolyzed foods based on their ELISA response profiles. Wheat beers typically showed a high reactivity to the G12 and Skerritt antibodies compared to the R5, whereas sourdough breads produced equal responses to the G12 and R5 antibodies and a comparatively higher response to the Skerritt antibody. Although some of the soy-based sauces showed non-specific responses with multiple R5 and G12 antibodies, their overall profile was distinguishable from the other categories of fermented foods.
Significance: This novel gluten-based competitive ELISA provides insight into the specificity of the fermentation process and the extent of hydrolysis. It has the potential to aid in the selection of appropriate hydrolytic calibration standards, leading to a more accurate estimate of gluten concentration.