Textured soy protein, which is commonly referred to as simply "TSP" in the food and cooking industries, is a food product that is usually used as a meat substitute in dishes that are made for vegetarians or made when meat is not available. Textured vegetable protein or "TVP" is a term that is commonly used synonymously with "textured soy protein." The product is often sold in flakes or in chunks and is used as a substitute in a number of dishes. For example, it often replaces meat when it is used in sandwiches such as veggie burgers or sloppy Joes. It may also be used in red sauce to create a vegetarian meat sauce for pasta dishes.
The key ingredient in textured soy protein is a kind of soy flour. As soy flour is much less expensive than meat, it makes a low-cost substitute. Some school lunch programs used textured soy protein in their menus in order to deliver a protein source while keeping costs down. For similar reasons, textured soy protein is often used in correctional facilities. The kinds of textured soy proteins that are used in schools and in prisons are often fortified with vitamins and minerals to make their nutritional value equivalent to that of the meat that they are substituting.
Some grocery stores sell textured soy protein, but it is most commonly used in industrial cooking and therefore is sold in bulk. There are, however, many kinds of packaged foods sold in many grocery stores that rely on textured soy protein as a key ingredient. One example is vegetarian breakfast patties. Some health food stores sell textured soy protein either in prepackaged containers or for purchased from bulk quantities.
Many people who keep a kosher diet have found textured soy protein to be a very useful product. This is because a kosher kitchen requires the separation of meat and dairy products, both in recipes and in the kitchenware. TSP is a great resource because it can replace meat without creating a problem by combining meat with dairy. Traditional lasagna, for example, is not a kosher dish if it is made with a meat sauce as one of the key components to the dish is a topping of cheese. If the sauce is made with TSP, however, it can be combined with cheese while keeping the dish kosher.