Science, Tech, Math › Science What Is Gluten? Chemistry and Food Sources Gluten Sources and Chemistry Share Flipboard Email Print Gluten is found in certain grasses related to wheat. Wheat and wheat flour, spelt, barley, and rye are sources of gluten. BSIP/UIG / Getty Images Science Chemistry Chemistry In Everyday Life Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated November 29, 2018 Gluten is a common allergen found in foods, yet do you know what exactly it is? Here's a look at gluten chemistry and the foods most likely to contain gluten. What Is Gluten? Gluten is a protein found exclusively in certain grasses (genus Triticum). It is a composite of two proteins, gliadin and a glutenin, bound to starch in the seeds of wheat and related grains. Gliadin and Glutenin Gliadin molecules mainly are monomers, while glutenin molecules typically exist as large polymers. What Does Gluten Do in Plants? Flowering plants, including grains, store proteins in their seeds to nourish plants when the seeds germinate. Gliadin, glutenin, and other prolamin proteins essentially are the building blocks used by the seeds as they sprout into plants. What Foods Contain Gluten? Grains that contain gluten include wheat, rye, barley, and spelt. Flakes and flour made from these grains contain gluten. However, gluten is added to many other foods, usually to add protein content, impart a chewy texture, or as a thickening or stabilizing agent. Foods that contain gluten include bread, grain products, imitation meats, beer, soy sauce, ketchup, ice cream, and pet foods. It is commonly found in cosmetics, skin products, and hair products. Gluten and Bread Gluten in flour is used to make bread. When the bread dough is kneaded, the glutenin molecules cross-link the gliadin molecules, forming a fibrous network that traps carbon dioxide bubbles produced by yeast or a leavening agent, such as baking soda or baking powder. The trapped bubbles make the bread rise. When bread is baked, the starch and gluten are coagulated, locking the baked goods into shape. Gluten binds water molecules in baked bread, which may be a factor in causing it to go stale over time. Rice and Corn Rice and corn contain prolamin proteins to support growth of seedlings, but they don't contain gluten! Gluten is a protein specific to wheat and other grasses in its family. Some people have chemical sensitivities to the proteins in rice or corn, but these are reactions to different molecules. What Causes a Gluten Allergy? An allergic reaction to gluten is celiac disease. It's estimated between 0.5% and 1% of people in the United States are allergic to gluten and that this frequency applies to other wheat-eating countries as well. The allergy is linked to an excessive immune response to partially digested gliadin.