A process for enriching the relative concentration of genistin from a mixture of isoflavones is described. In accordance with one aspect of the invention, the process comprises providing a material containing a mixture of isoflavones, extracting the material with an aqueous organic solvent solution, adding calcium oxide or calcium hydroxide to the extract to form calcium-isoflavone complexes and separating precipitated calcium-isoflavone complexes from the extract. The precipitated calcium-isoflavone complexes contain a higher concentration of genistin complexes than daidzin and glycitin complexes.