A process is disclosed for producing an improved modified plant protein having thermoplastic and forming properties similar to casein and caseinate salts. The process comprises making an aqueous slurry of a plant protein material and an alkali metal carbonate, adjusting the pH, reacting the carbonate with the protein, admixing the slurry with a peroxide, neutralizing the slurry, removing steam volatile flavor components from the slurry, and then drying the neutralized slurry. The process produces a product which is improved in odor, taste and color.