gluten

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Gluten ([ gluˈtʰeːn ] listen ? / I , also [ ˈgluːtʰən ]; from the Latin glūten “ glue ”) or gluten is a collective term for a mixture of proteins that occurs in the seeds of some types of grain . Audio file / audio sample

Stretch test of a washed-out wheat gluten.

The term glue is often used synonymously with gluten, but is defined as a mixture of proteins, lipids and carbohydrates that remains after washing out the soluble components and starch from a dough . When water to cereal flour is added, then when the gluten forms pasting from the flour and a rubbery elastic mass, namely the dough. The glue it contains is created by the irreversible formation of a three-dimensional structure of the proteins. The glue is of central importance for the baking properties of a flour.

construction

Gluten is made up of the two Osborne fractions prolamine (soluble in a 70% ethanol solution ) and gluteline (soluble in alkaline), whereby (in contrast to enzymes and other cytoplasmic proteins) they are reserve proteins ( storage proteins in seeds, roots and Sprout tubers). In wheat they are referred to as " gliadins " (prolamine fraction ) and " glutenins " (glutelin fraction ) and are divided into the subgroups "high molecular" gliadins and "low molecular" gliadins as well as "medium molecular" glutenins (ω1,2-gliadins) and "low molecular glutenins" ( α- and β-gliadins). Prolamins and glutelins are found in wheat in a ratio of around 1: 1 and, at around 80%, represent the largest protein fraction in terms of quantity.

Food technological importance

In combination with water, gluten forms what is known as glue protein . This forms the dough structure for bread and pastries. Bread in the form of a loaf (in contrast to flatbread ) can only be baked from flours with gluten . The amount of gluten is decisive for the baking ability ("gas holding ability") of wheat flours . Gluten is expandable and provides in the wheat dough on the Gare that the fermentation gas ( carbon dioxide ) is kept, and thus the pastry may rise. In the finished baked goods, the curdled glue structure ensures that the baked goods retain their shape.

The miller's job is to mix batches of wheat so that the glue quality is optimal for the production of bread and biscuits . In commercial wheat flour, the gluten content in the dry matter is around 13%. Since dry glue can absorb two to three times its own weight in water, the water-containing glue content in dough is around 30% to 35%.

In the laboratory, glue is washed out by rinsing a dough with saline solution until the iodine sample shows that there is no more starch in the washout water . The gum-like glue remains. The properties of the glue (stretchy-elastic or stubborn-short) are mainly determined by the characteristics of the wheat variety. The quality of the glue can be determined in the laboratory through various tests (strain test with the extensograph or gluten index with the Glutomatic device).

When the glue is washed out, the protein composition changes because the essential amino acid lysine in particular is partially removed together with the starch.

Grains with a high gluten content are spelled (10.3 g / 100 g flour type 630), wheat (Gliadin, 8.66 g / 100 g flour type 405), kamut , emmer , einkorn and durum wheat . Rye (Secalinin, 3.2 g / 100 g flour type 815), oats (Avenin, 5.6 g / 100 g whole grain flour) and barley (Hordenine, 5.6 g / 100 g whole peeled grain) have a lower proportion of gluten ). Grains such as teff , millet , maize and rice , as well as pseudo-cereals such as quinoa , amaranth and buckwheat are gluten-free. Gluten is a component of foods made from the appropriate grains, and it is the main ingredient for seitan , a meat substitute also offered as “wheat meat ” . Gluten-free flour is available in stores; however, it behaves differently than flour containing gluten. The quantities given for individual ingredients can therefore differ from classic recipe specifications. Baked goods without gluten are often not as airy and juicy as with conventional flour, because gluten also ensures good pore formation and a firm crumb when baking .

Gluten-free beer is also available in stores .

A food with a maximum gluten content of 20 mg / kg may be designated as “gluten-free”; the term only guarantees the reduced presence, not the complete absence of gluten. Food that may contain traces of cereals containing gluten (including oats) must be labeled accordingly within the EU in accordance with the Food Information Regulation .

  • Ripe wheat grains contain gluten

  • Rye grains contain gluten

  • Spelled grains contain gluten

  • As a gluten-free beer being instructed from sorghum in an American supermarket

  • A piece of seitan ( "wheat meat" ) of gluten

  • Japanese seitan (yaki-fu, 焼 き 麩) made from gluten

Health aspects

Celiac disease

Celiac disease is an inflammatory disease of the intestinal lining that, if left untreated, can have far-reaching health consequences. It occurs in less than one percent of the population worldwide. In Germany, around one in 270 to 500 people is affected by celiac disease.

Gluten ataxia

Gluten ataxia is a neurodegenerative autoimmune disease characterized by impaired movement coordination that can be accompanied by muscle twitching .

Dermatitis herpetiformis Duhring

Dermatitis herpetiformis Duhring is a blistering skin condition with severe itching that mostly occurs in people with celiac disease.

Veterinary medicine

In the Border Terrier, the Canine Epileptoid Cramping Syndrome , a disease with epilepsy-like seizures, is viewed as a non-bowel-associated form of gluten intolerance.

Non-Celiac Disease-Non-Wheat Allergy-Wheat Sensitivity

The non-celiac gluten sensitivity (Engl. Non-celiac gluten sensitivity , NCGS ) is probably not by gluten, but other wheat constituents, such as amylase trypsin inhibitors triggered.

literature

  • Wilfried Seibel (Hrsg.): Commodity knowledge of cereals - ingredients, analysis, cleaning, drying, storage, marketing, processing. Agrimedia, Bergen Du 2005, ISBN 3-86037-257-2 .
  • Jessica R Biesiekierski: What is gluten? In: Journal of Gastroenterology and Hepatology. 32, 2017, p. 78, doi: 10.1111 / jgh.13703 .
  • S. Drago, R. El Asmar et al. a .: Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines. In: Scandinavian journal of gastroenterology. Volume 41, Number 4, April 2006, pp. 408-419, doi: 10.1080 / 00365520500235334 , PMID 16635908 .
  • KM Lammers, R. Lu u. a .: Gliadin induces an increase in intestinal permeability and zonulin release by binding to the chemokine receptor CXCR3. In: Gastroenterology. Volume 135, number 1, July 2008, pp. 194-204.e3, doi: 10.1053 / j.gastro.2008.03.023 , PMID 18485912 , PMC 2653457 (free full text).
  • J. Hollon, EL Puppa, et al. a .: Effect of gliadin on permeability of intestinal biopsy explants from celiac disease patients and patients with non-celiac gluten sensitivity. In: Nutrients. Volume 7, number 3, March 2015, pp. 1565–1576, doi: 10.3390 / nu7031565 , PMID 25734566 , PMC 4377866 (free full text).
  • Johannes Gudow: Nutrition: The Legend of Bad Gluten . In: Die Zeit , No. 48/2013

Web links

Commons : Gluten  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ Stephan Bopp: Gluten like ten or how fast? Canoo, November 17, 2011.
  2. ↑ With a long stressed first syllable and a short second syllable, see Latin pronunciation # stress rules .
  3. ↑ Gerhard Eisenbrand: RÖMPP Lexikon Lebensmittelchemie . 2nd edition, 2006. Georg Thieme Verlag, 2014, ISBN 978-3-13-179282-2 , p. 460 ( limited preview in the Google book search).
  4. ^ Wilhelm Meyer zu Venne: The world of the waffle. Books on Demand , 2013, ISBN 978-3-8482-7628-8 , p. 58 ( limited preview in Google Book Search).
  5. ↑ TB Osborne: The chemistry of the protein bodies of the wheat kernel. Part I. The protein soluble in alcohol and its glutaminic acid content. In: American Journal of Physiology . 1905; 13: 35-44.
  6. ↑ Implementation of the Gluten Index (PDF; 325 kB).
  7. ^ Burghard Kirsch: Milling technology, materials science. Composition, study, evaluation and use of grain and grain products . 8th edition. Bayerischer Müllerbund, Munich 2016, ISBN 978-3-9812436-6-6 .
  8. ↑ Compendium: Our Daily Bread Diverse. Precious. Tasty (PDF) Flyer of the Competence Center for Nutrition Bavaria, 2017
  9. ^ Standard For Foods For Special Dietary Use For Persons Intolerant To Gluten . In: Food and Agriculture Organization of the United Nations , World Health Organization (ed.): Codex_Alimentarius : International Food Standards . CXS118-1979 (English, 3 pp., Fao.org [PDF]).
  10. ↑ Association Of European Celiac Societies : AOECS Standard for Gluten-Free Foods: Technical requirements for licensing the Crossed Grain symbol . Brussels September 2016 (English, aoecs.org [PDF]).
  11. ↑ German Celiac Society : Licensing of the gluten-free symbol "Strikethrough ear". Retrieved July 25, 2020 .
  12. ↑ Johannes Gudow: Nutrition: The legend of bad gluten . In: Die Zeit , No. 48/2013
  13. ^ German Celiac Society Ev (Dzg): DZG - The disease picture. In: dzg-online.de. Retrieved June 9, 2015 .
  14. ↑ M. Lowrie et al .: The Clinical and Serological Effect of a Gluten-Free Diet in Border Terriers with Epileptoid Cramping Syndrome. In: Journal of veterinary internal medicine / American College of Veterinary Internal Medicine. Volume 29, number 6, 2015 Nov-Dec, pp. 1564-1568, doi: 10.1111 / jvim.13643 , PMID 26500168 .
  15. ↑ JR Biesiekierski, JG Muir, PR Gibson: Is gluten a cause of gastrointestinal symptoms in people without celiac disease? In: Current allergy and asthma reports. Volume 13, Number 6, December 2013, pp. 631-638, doi: 10.1007 / s11882-013-0386-4 , PMID 24026574 (review).
  16. ↑ JR Biesiekierski, J. Iven: Non-celiac gluten sensitivity: piecing the puzzle together. In: United European gastroenterology journal. Volume 3, number 2, April 2015, pp. 160-165, doi: 10.1177 / 2050640615578388 , PMID 25922675 , PMC 4406911 (free full text) (review).
  17. ↑ Victor F. Zevallos, Verena Raker, Stefan Tenzer, Carolina Jimenez-Calvente, Muhammad Ashfaq-Khan: Nutritional Wheat Amylase-Trypsin Inhibitors Promote Intestinal Inflammation via Activation of Myeloid Cells . In: Gastroenterology . tape 152 , no. 5 , April 2017, p. 1100–1113.e12 , doi : 10.1053 / j.gastro.2016.12.006 ( elsevier.com [accessed on July 20, 2020]).