Soybeans are rich in both protein and oil, and extracting the oil for cooking use leaves behind a high-protein soy "flour" that's a high-value addition to vegetarian diets. That flour is the base ingredient for textured vegetable protein, also known as "TVP" or "textured soy protein." It's soy flour that has been formed and extruded to resemble meat, then dried into compact, long-lasting granules or morsels. It's typically used as a meat replacement by vegetarians or as an inexpensive meat extender by omnivores.
Rehydrating Your Soy Protein
Textured soy protein is completely dry when it comes out of the package, which is why its shelf life is essentially infinite. Before you can use it in most recipes, it must be rehydrated. In the common small-grain form, which resembles ground beef, the soy can simply be soaked in hot water or -- for extra flavor -- broth. You'll need almost a cup of water for every cup of TVP. It doubles in size and triples in weight after soaking, so 1 cup of dry soy equals 2 cups of beef crumbles, and 5 to 6 ounces by weight equals approximately a pound of ground beef. Larger pieces of soy protein, formed to resemble strips or cubes of meat, require simmering for 20 to 30 minutes until they're tender.
Soy Protein "Crumbles"
The texture and flavor of a juicy steak is nearly impossible to replicate, but ground beef is a much easier target. It's relatively neutral in flavor and slightly chewy, which means it's readily simulated by TVP. Once rehydrated, the crumbly protein can be substituted directly for the ground beef in most recipes. It absorbs flavors from its surroundings like a sponge, so sauteing it briefly with onions, garlic, celery, mushrooms or other savory ingredients does wonders for its taste. It can also be cooked and rehydrated simultaneously in chili or the tomato sauce for pasta dishes, soaking up both the sauce's flavors and its excess moisture.
Some soy protein is sold in the form of molded strips or bite-sized morsels, designed to simulate the look and feel of chicken strips or stew meat. These can be used almost anywhere their meat equivalents are used, though their flavor and texture are not exactly the same. If you're new to cooking with soy protein, it's best to incorporate them into dishes with lots of other flavors and textures to mask the differences. A stir-fry with ginger, soy sauce and lots of tender-crisp vegetables is a good option; or dishes with clinging Asian-style sauces such as teriyaki or sweet-and-sour. The bold flavorings of Mexican and Indian food also work well in soy, which then can be paired with rice, beans or flatbreads.
In its dehydrated form, textured vegetable protein is far too dry to support bacterial life, and its storage life can be measured in years. Flavored versions are best consumed within a year, but that's primarily because the flavorings deteriorate over time. That changes once the soy is rehydrated, which makes it as perishable as any other high-protein food. Hydrated TVP should be packaged and refrigerated if it's not going to be used immediately. It's safe in the refrigerator for two or three days, and if well-wrapped, it will retain its quality for up to six months in your freezer.