Research from Edith Cowan University (ECU) has found that several purportedly low or reduced gluten beers contain equivalent or higher amounts of gluten proteins than regular beers.
Coeliac disease (CD) is a common but under-diagnosed immune-based condition triggered by gluten, causing the body’s immune system to react to gluten by attacking itself. An estimated that one-in-70 Australian’s live with CD (with only 20 per cent diagnosed). Along with Australians that opt for a gluten-free diet, a growing customer base exists for food and beverage producers.
A survey conducted by Professor Michelle Colgrave and Dr Mitchell Nye-Wood at ECU investigated gluten content in a range of beers and found that while some regular and gluten-reduced beers contained very low levels of gluten proteins, others did not fare as well.
Gluten is normally detected using the enzyme-linked immunosorbent assay (ELISA) method. However, in foods or beverages containing barley and where a fermentation process is used, the ELISA method can deliver variable results as gluten proteins are broken down into fragments that may be unrecognisable by the ELISA antibodies.
Beer production involves multiple steps where gluten proteins can be modified, degraded or precipitated. The remaining gluten concentrations are typically above CD regulatory thresholds but can be further decreased by treatments that aim to precipitate and filter out the gluten. Alternatively, enzymes can be added to digest gluten proteins.
Colgrave said that beer, by definition, contains barley, and while some beers were found to have very low levels of gluten protein, there were always difficulties with batch-to-batch consistency and ensuring no contamination.
“An exception does exist; there is a new variety of barley that was bred by the Commonwealth Scientific and Industrial Research Organisation to not contain any appreciable level of gluten, this is called Kebari barley, and has been used to make beer,” said Colgrave.
Colgrave explained that while this beer was safe for those with CD, it was not commercially available in Australia. Instead, those with CD could consider beer made using non-gluten grains like millet, sorghum, buckwheat, or corn instead of barley malt.
“To be on the safe side, people with CD should avoid beer made using cereal grains irrespective of the gluten reduction method. Despite the reduced gluten label, there is a risk that it contains gluten protein fragments that can provoke a reaction in their gut,” said Colgrave.
For brewers, Colgrave said that the sandwich ELISA method would be sufficient for gluten quantitation of raw ingredients used in the production of gluten-free beers to test for the presence of contaminants.
However, for beers produced using gluten-reduction strategies, even competitive ELISA may deliver variable results. Techniques such as liquid chromatography mass spectrometry (LC-MS) offered an alternative for quality control assessment.
“When using traditional barley malts, there will be several hurdles that will be difficult to overcome. Not all maltsters or breweries will have access to equipment like we have in our lab that provides a highly sensitive and accurate method for detecting gluten.
“There would be an ongoing need for assessing treatment efficiency, batch-to-batch consistency, and the risk of contamination. In summary, our paper shows that in practice most low-gluten products have detectable gluten,” Colgrave said.
