Patent ID: 8142832

Claim:
A method for obtaining a β-conglycinin-rich isolated protein fraction and a glycinin-rich isolated protein fraction from a vegetable protein source comprising: obtaining a defatted vegetable protein source; extracting said source with a dilute alkali with a pH of approximately 7 to approximately 11 to form a mixture of the proteins present in said vegetable source; obtaining a supernatant protein extract from said mixture, by adding a combination of a source of calcium to achieve an amount of from about 5 mM to about 10 mM calcium ions, and a reducing agent of sulfur dioxide to achieve an amount of sulfur dioxide of from about 5 mM to about 10 mM to form a slurry, wherein said combination of calcium and sulfur dioxide fractionating agents eliminate and intermediate fraction; and adjusting the pH of said slurry to a pH of approximately 7 to approximately 5 to obtain a precipitate which is enriched in glycinin and a supernatant which is enriched in β-conglycinin as compared to percentages of each protein in the original mixture.