Soy protein is a natural vegetable protein made from soy bean. Soy protein products come in three basic categories: isolated soy protein, concentrated soy protein and textured soy protein. Isolated soy protein is extracted from defatted soy flakes through removing most of the fat and carbohydrates, it contains more than 90 percent protein on a dry basis. Concentrated soy protein is made by removing the water-soluble carbohydrates from defatted and dehulled soybeans. It retains most of the fiber in the original soy beans and containing at least 68% protein on a dry basis. Textured soy protein is produced from defatted soy flour, soy flakes or soy concentrated by an extrusion process, which can form a fibrous structure which is almost similar to meat.