To being with, look for hydrolyzed plant protein. Unless the source is known, it could possibly contain gluten.
Also look for wheat, wheat bran, wheat germ, cereal, bread, malt, caramel coloring, pasta, starch semolina, pudding, soy sauce and miso (many contain wheat), barley malt, rye, durham, matzo or matza, graham, beer, orzo, couscous, breadcrumbs, bouillon, and even Textured Vegetable Protein (TVP) which is usually made from soy but may also contain wheat.
If the product or homemade item contains a cereal grain such as wheat, rye or barley, then it has gluten in it. Understand that gluten can be separated from the starch of the plant but not to the degree of one-hundred percent. There will still be small of amounts of gluten in certain plant starches. For those who are extremely sensitive, they may need to be avoided so look for starch or plant starch.
The gluten of corn and rice does not contain gliadin, and gliadin is part of the two proteins that make up gluten in the other cereal grains of which glutenin is the second part. Though corn and rice do not contain gluten, many who are sensitive to gluten, often find themselves being sensitive to other grains and pseudo-grains.
Prolamins are other proteins found in the seeds of cereal grains beyond gliadin and glutenin. There may be intolerance issues with this component as well.
Oats are also often coated in gluten and unless certified gluten free, if you are intolerant to gluten, you must also avoid oats.
Where Might Gluten be Hiding in My Food?
Gluten may be hiding in ingredients such as hydrolyzed plant protein, vegetable protein, starch, caramel coloring, malt, gravies, thickened soups, thickened soup bases used in recipes, stews, beer, distilled spirit beverages such as bourbon or vodka, malt vinegar, seitan, soy and miso, and distilled vinegars made from grains.
Sauces and condiments are good places to start looking for gluten. Also consider the vinegar source of a favorite ketchup/catsup and other processed food containing vinegar. If the vinegar is distilled grain-based vinegar, it may have gluten in it – specifically, an example is malt vinegar, however, there are others.
What Are Some Other Terms for Gluten That I Should Watch Out For?
Not all are guaranteed to be gluten but without knowing the source of the raw materials or manufacturing processes, there may be gluten in all of these especially since grocery stores contain many products not made in the United States: Hydrolyzed vegetable protein, plant protein, starch, Textured Vegetable Protein (TVP normally made from soy but may contain wheat), maltodextrin (can be made from corn or wheat), monosodium glutamate (MSG), lecithin and the ubiquitous “natural flavoring.”