Isolated Soja Protein [ISP] has a protein content of 90% and should be used in cooked sausages to increase mouthfeel ("bite"). The emulsion remains firm after cooking.
Soya Concentrate has a protein content of 70% and is normally used for making emulsions, such as chicken skin emulsions to reduce material cost.
A typical formulation is 1+5+5: 1 part soya isolate or concentrate 5 parts of water 5 parts of vegetable oil or animal fat (e. g. chicken skin).