Can I make non-enriched soy protein powder at home since the store-bought products are expensive?
I suspect that the main ingredient in the soy powder you are using is isolated soy protein . It is a very concentrated form of protein, and is it contains about 90% protein. A piece of beef steak would contain about 20% protein. Soy protein isolate is made through commercial processes, and it is not possible for you to make it in your home. However, you may want a start looking for a less expensive forms of soy protein. For example , check out your local health food grocery store and see if they sell either soy flour or textured soy protein.
