Wheat gluten frequently appears on the ingredients labels of dry pet foods, where it serves as a bulking agent and helps the meat meal retain its shape. More commonly, though, it's found in human food. In fact, most grain-based foods that you eat contain gluten, both added and naturally occurring. For most people, it's just another food additive -- but for others, it means the difference between health and illness.
Gluten
Whole grains contain small amounts of protein. In the case of wheat, rye and other related grains, that protein is gluten. It helps provide cell structure to keep the plant upright while it grows and remains an essential part of the flour into which the harvested grain is ground. Sometimes, a portion of the gluten is extracted from the ground grain and sold separately as vital wheat gluten, which is the form of gluten used as a food additive.
Naturally Occurring
When naturally occurring, gluten provides structure to foods made with the flour, the same way it did for the plant. Different flours have different gluten contents, and those with the highest amount of gluten are used to make stiff, chewy breads, while those with the lowest content are used to make softer, more delicate items such as cake. When a dough made with a high gluten content is kneaded, the kneading action lengthens and stretches the gluten fibers, which become stronger the more they are manipulated. As the dough rises, the gluten strands trap the gas bubbles produced by the yeast respiration, producing the air pockets you see when you cut a slice of bread.
Additive
Some flours, like whole wheat, tend to produce a heavier, denser loaf. Adding a little vital wheat gluten helps the flour's native gluten form more and stronger air pockets, resulting in a fluffier loaf. It's also useful when cooking with low-carb flours such as tapioca or rice -- these flours either don't contain gluten or only contain very small amounts so they tend to produce a dense, dry, crumbly loaf. The addition of vital wheat gluten helps create the structure necessary to trap air and help the bread rise to produce a lighter loaf.
Avoiding Gluten
People with celiac disease must steer clear of gluten or risk a flare-up of intestinal inflammation and the accompanying ill effects. A gluten-free diet means avoiding anything containing wheat, barley, rye, semolina, spelt, kamut and other related grains. Even eating foods processed alongside gluten-containing foods is a hazard. This makes it difficult to find safe versions of beer, bread, crackers, baked goods, pasta and even condiments and soups. Instead, a gluten-free diet relies on fruits, vegetables, meats and alternative grains such as quinoa, rice, tapioca, amaranth and corn.
