Gluten

The term "gluten" derives from Latin "gluten" meaning glue. Our gluten is a mixture of proteins found in wheat grains. This refers particularly to prolamins and glutelins, which take their typical names from the respective type of cereal. Gluten in wheat consists of the two proteins: gliadin and glutenin, sometimes also referred to as “glue”. This glue forms a special, elastic protein scaffold when it comes in contact with water, providing the basis for shaping specific baked goods. This scaffold is responsible for dough rising during the baking process and also for maintaining dough shape after baking.

A fraction of the population cannot metabolise gluten. Over-sensitivity to specific compounds causes an inflammatory reaction of the bowel tissue, resulting in the destruction of intestinal epithelial cells. Thus, it is very difficult to almost impossible for those affected to ingest nutrients, causing them to remain in the intestine undigested. This metabolic dysfunction is called coeliac disease and can only be treated following a strict, gluten-free diet, based on current knowledge levels.

The AGES Institute for Food Safety Vienna tests gluten in foodstuffs as part of a market audit and for awarding the gluten-free symbol (see testing).

The term "gluten" derives from Latin "gluten" meaning glue. Our gluten is a mixture of proteins found in wheat grains. This refers particularly to prolamins and glutelins, which take their typical names from the respective type of cereal. Gluten in wheat consists of the two proteins: gliadin and glutenin, sometimes also referred to as “glue”. This glue forms a special, elastic protein scaffold when it comes in contact with water, providing the basis for shaping specific baked goods. This scaffold is responsible for dough rising during the baking process and also for maintaining dough shape after baking.

A fraction of the population cannot metabolise gluten. Over-sensitivity to specific compounds causes an inflammatory reaction of the bowel tissue, resulting in the destruction of intestinal epithelial cells. Thus, it is very difficult to almost impossible for those affected to ingest nutrients, causing them to remain in the intestine undigested. This metabolic dysfunction is called coeliac disease and can only be treated following a strict, gluten-free diet, based on current knowledge levels.

The AGES Institute for Food Safety Vienna tests gluten in foodstuffs as part of a market audit and for awarding the gluten-free symbol (see testing).

Gluten-Free Diet

A gluten-free diet is a type of diet without the specific proteins contained in the cereals wheat, rye, barley and possibly even oats, as well as their related grains and hybrids (spelt, triticale, green spelt, Emmer wheat, Khorasan wheat,…). "Gluten" is the name given to all the proteins from the grains mentioned above and that are harmful to people suffering from coeliac disease.

Gluten is not only found in products that obviously contain any compounds of the cereals listed above, but is often used as an ingredient in processed foods.

As a result, food manufacturers and retailers offer "gluten-free" products during the processing of which a "contamination" with gluten or cereals containing gluten is avoided by all means possible. These products can be identified by a symbol featuring a crossed grain symbol. Products are subject to mandatory examinations for gluten content at an AGES laboratory before they can bear the "gluten-free" logo.

The requirements that must be met by gluten-free food are defined in both the Codex Alimentarius and the appropriate EU Regulation 41/2009. Unlike with all other food allergens, a legal threshold value to regulate the labelling of gluten as an allergen in foodstuffs was introduced for the very first time on 20th January, 2009.

A difference is made between

Foodstuffs labelled as "GLUTEN-FREE": these foods must not exceed a gluten content of 20mg/kg. This includes foods that are gluten-free by nature and foods the natural gluten of which has been removed.

Foodstuffs labelled as "VERY LOW GLUTEN CONTENT": foods carrying this label may contain a gluten level over 20 mg/kg but below 100 mg/kg.

Testing

It is not sufficient just to find evidence of gluten in foods, given the labelling threshold value. The determination of gluten in foodstuffs can be done in various ways. The quantitative recording of proteins causing coeliac disease is a suitable determination method, in addition to DNA methods (based on information on genetic material).

Specific genes (DNA) in gluten-producing plants are identified using PCR (Polymerase Chain Reactions) allowing for the quantification of gluten via comparisons with reference materials.
The method used most frequently is the determination of the proteins known directly to cause coeliac disease. This is complemented by immune-chemical procedures such as ELISAs (Enzyme Linked Immunosorbent Assay), in addition to mass spectrometry. An ELISA is an analytical test making use of the specific interaction between an antigen (the protein to be determined, including gliadin) and its antibody.

The AGES Institute for Food Safety Vienna uses a gliadin-specific ELISA (R5 antibody) to determine gluten levels in foods. The gluten present in a sample binds to specific antibodies. The resulting colour reaction of the gliadin antibody complex will form a measurable colour substance. The intensity of this colour is proportional to the amount of gliadin contained in the sample, thus, making the quantification of gliadin possible.

More than 200 samples were tested for excessive gluten content as part of a market audit and for awarding the gluten-free symbol in 2010.

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