Wheat glutenin detection by PCR

The current method used to detect gluten in foods is an enzyme-linked immunosorbant assay (ELISA) technique which detects the gliadin component of gluten. This method shows cross-reactivity with barley and rye gluten, and is therefore not suitable to distinguish gluten that originates from wheat. Researchers from the Central Food Technological Research Institute in India have developed a PCR test to detect the presence of the gene responsible for the production of the protein glutenin in wheat.

To identify the gene responsible for the production of the protein glutenin in wheat, the researchers compared the DNA sequences for the low molecular weight subunit of the glutenin protein in wheat, barley and rye. They identified the sequence divergence between the three cereals and designed a PCR test that would be specific for the wheat glutenin sequence. A short sequence (135bp) was identified, which also makes it an ideal target to look for in food where much of the DNA has been degraded through processing methods.

The authors believe this method may complement existing methods used to detect wheat in highly-processed foods. It may also help when manufacturers wish to specifically label for the presence or absence of wheat.

Reference: Debnath et al. 2009. Food Research International. Vol 42 (7) pp. 782-787.