Soy protein is a protein that is isolated from soybean. It is made from soybean meal that has been dehulled and defatted. Dehulled and defatted soybeans are processed into three kinds of high protein commercial products: soy flour, concentrates, and isolates. Soy protein isolate has been used since 1959 in foods for its functional properties.
Soybean protein is a complete protein since it provides all of the essential amino acids for human nutrition. Soybean protein is essentially identical to that of other legume pulses, and is one of the least expensive sources of dietary protein. For this reason, soy is important to many vegetarians and vegans.
Soy protein is used to create textured soy protein, by extruding defatted soy flour mixed with water through dies to create various shapes, which are then used in various preparations.