Post by kickingfrog on Oct 29, 2012 14:15:12 GMT
by Tricia Thompson, MS, RD, The Gluten-Free Dietitian
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Why the confusion over barley malt extract?
It is very tricky to test for barley contamination in food. One of the assays (sandwich omega-gliadin ELISA) severely underestimates gluten contamination from barley; the other (sandwich R5 ELISA) overestimates gluten contamination from barley by a factor of 2. And when it comes to testing for gluten in a hydrolyzed product (a product that has been partially broken down), such as barley malt extract, the test that usually overestimates barley contamination may now underestimate it. It really is a confusing situation! Fortunately, there is an assay available for testing hydrolyzed ingredients. It is called the competitive R5 ELISA.
How much gluten does barley malt extract contain?
When 3 barley malt extracts were tested for gluten using the competitive R5 ELISA, they contained approximately 320, 960, and 1300 parts per million (ppm) gluten. Taking into account the fact that the R5 ELISA may overestimate barley contamination by a factor of 2, the extracts more likely contained approximately 160, 480, and 650 ppm gluten.
Obviously, when barley malt extract is an ingredient in a food product, such as breakfast cereals, waffles, and pancakes, the ppm gluten content of the final food product will be far less than the ppm gluten content of the extract. In one study that assessed the gluten content from barley in two breakfast cereals containing barley malt extract, one product contained 795 ppm gluten; the other 171 ppm gluten.
Might some products containing barley malt extract have less than 20 ppm gluten?
Maybe. But in order to know for sure that a product containing barley malt extract has less than 20 ppm gluten a manufacturer has to use the best available assay to test their product. Unfortunately, it is difficult to know the best test to use for a given product.
Thomas Grace, CEO of Bia Diagnostics, a food testing facility in Burlington, Vermont, says the following concerning the use of barley malt extract in gluten-free foods: “In my opinion until there is a reliable method that can detect all hydrolyzed hordeins (the harmful protein in barley) in these extracts and correlate them with minimal reactive thresholds, manufacturers might want to stay away from barley malt extract in gluten free labeled products. We might find that some barley malt extracts are fine for persons with celiac disease, but until we know that for sure and have a reliable method for verification one should proceed on the side of caution.”....
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Tricia Thompson, M.S., RD is a nutrition consultant, author and speaker specializing in celiac disease and the gluten-free diet. She is the author of The Gluten-Free Nutrition Guide (McGraw-Hill) and co-author of The Complete Idiot’s Guide to Gluten-Free Eating (Penguin Group). For more information, visit www.glutenfreedietitian.com.
www.glutenfreedietitian.com/CurriculumVitae2010.pdf
www.ncbi.nlm.nih.gov/pubmed/18926134
cat.inist.fr/?aModele=afficheN&cpsidt=14792552
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Why the confusion over barley malt extract?
It is very tricky to test for barley contamination in food. One of the assays (sandwich omega-gliadin ELISA) severely underestimates gluten contamination from barley; the other (sandwich R5 ELISA) overestimates gluten contamination from barley by a factor of 2. And when it comes to testing for gluten in a hydrolyzed product (a product that has been partially broken down), such as barley malt extract, the test that usually overestimates barley contamination may now underestimate it. It really is a confusing situation! Fortunately, there is an assay available for testing hydrolyzed ingredients. It is called the competitive R5 ELISA.
How much gluten does barley malt extract contain?
When 3 barley malt extracts were tested for gluten using the competitive R5 ELISA, they contained approximately 320, 960, and 1300 parts per million (ppm) gluten. Taking into account the fact that the R5 ELISA may overestimate barley contamination by a factor of 2, the extracts more likely contained approximately 160, 480, and 650 ppm gluten.
Obviously, when barley malt extract is an ingredient in a food product, such as breakfast cereals, waffles, and pancakes, the ppm gluten content of the final food product will be far less than the ppm gluten content of the extract. In one study that assessed the gluten content from barley in two breakfast cereals containing barley malt extract, one product contained 795 ppm gluten; the other 171 ppm gluten.
Might some products containing barley malt extract have less than 20 ppm gluten?
Maybe. But in order to know for sure that a product containing barley malt extract has less than 20 ppm gluten a manufacturer has to use the best available assay to test their product. Unfortunately, it is difficult to know the best test to use for a given product.
Thomas Grace, CEO of Bia Diagnostics, a food testing facility in Burlington, Vermont, says the following concerning the use of barley malt extract in gluten-free foods: “In my opinion until there is a reliable method that can detect all hydrolyzed hordeins (the harmful protein in barley) in these extracts and correlate them with minimal reactive thresholds, manufacturers might want to stay away from barley malt extract in gluten free labeled products. We might find that some barley malt extracts are fine for persons with celiac disease, but until we know that for sure and have a reliable method for verification one should proceed on the side of caution.”....
************************************
Tricia Thompson, M.S., RD is a nutrition consultant, author and speaker specializing in celiac disease and the gluten-free diet. She is the author of The Gluten-Free Nutrition Guide (McGraw-Hill) and co-author of The Complete Idiot’s Guide to Gluten-Free Eating (Penguin Group). For more information, visit www.glutenfreedietitian.com.
www.glutenfreedietitian.com/CurriculumVitae2010.pdf
www.ncbi.nlm.nih.gov/pubmed/18926134
cat.inist.fr/?aModele=afficheN&cpsidt=14792552
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