The options for gluten-free foods are growing for for people with celiac disease, non-celiac gluten sensitivity, and wheat allergy. German scientists, reporting in the American Chemical Society’s Journal of Agricultural and Food Chemistry, have developed a more reliable way for manufacturers to detect gluten in purified wheat starch, a common ingredient in foods labeled gluten-free.1
Gluten is a mixture of proteins in the starch of wheat, rye, barley grains (and oats depending on your source). When gluten can be broken down into two subgroups: prolamins (wheat gliadins) and glutelins (wheat glutenins). Current testing for gluten in foods involves running an enzyme-linked immunosorbent assay, or ELISA, that measures the amount of wheat gluten in the food. Although the method determines gliadin levels accurately, its measurements of glutenins are less reliable. Katharina Anne Scherf and her colleagues sought to find a more comprehensive test.
The researchers combined gel-permeation high-performance liquid chromatography with fluorescence detection to develop a sensitive technique that can detect both gliadins and glutenins in purified wheat starch. The new method identified higher amounts of gluten in 19 out of 26 starch samples than the ELISA analyses did. And, according to the new test, 12 samples that had been labeled gluten-free contained between 25.6 and 69 milligrams of gluten per kilogram of starch. The U.S. Food and Drug Administration and the United Nations’ Food and Agriculture Organization have set the maximum limit for gluten in products labeled gluten-free at 20 mg/kg.2