A method of treating a proteinaceous material having a first concentration of .beta.-conglycinin, the method including combining the proteinaceous material with an enzyme to form a reaction mixture, the reaction mixture initially having a pH of at least about 7.0 standard pH units, allowing the enzyme to hydrolyze .beta.-conglycinin present in the reaction mixture to form a proteinaceous intermediate, and inactivating the enzyme present in the reaction mixture after a reaction period to form a proteinaceous product, the proteinaceous product having a second concentration of .beta.-conglycinin, the second concentration of .beta.-conglycinin being at least 99 percent less than the first concentration of .beta.-conglycinin.