I've got soy and use it as a filler in sausages, but it's like a smooth paste and doesn't 'clump up' or take on the properties of ground beef. In the 60's and 70's we had 'ground beef - soy added' and it was an extender and was almost indistinguishable with regular ground beef; you'd add a packet to 10 lbs of ground beef and it would swell up and make up to 30 lbs of meat mix; tasted great in meatballs, meatloaf, etc.
I get mine rfrom Butcher Packer. I use it in many sausage recipes as a binder and it is almost 100% protein. It also helps retain natural juices in the product when cooked. My usual ration is about 5% by weight.