Abstract: A method is provided for the purification and concentration of soy protein comprising mixing an aqueous solution including soy protein along with other water soluble moieties including sugars, salts, and phytins with a solid crosslinked polymer gel selected from the group consisting of N-substituted polyacrylamides and copolymers of N-substituted polyacrylamides; swelling the gel to absorb a portion of the water and other water soluble moieties including sugars, salts, and phytins from the aqueous solution by substantially maintaining the temperature of the gel at a preselected temperature below the lower critical solution temperature of the gel, to yield a concentrated soy protein solution; and separating the concentrated soy protein solution from the swollen gel. The concentrated soy protein solution may be repeatedly subjected to the gel treatment depending on the desired purity of the protein and the desired solids concentration.