FIELD: food industry, medicine. SUBSTANCE: vegetable material comprising protein and at least one isoflavone compound is extracted with an aqueous extractant at pH value above the protein isoelectric point, preferably, at alkaline pH value. Protein and isoflavones are solubilized with extractant. Extractant containing protein and isoflavones is separated from insoluble vegetable matters to obtain protein extract followed by brought about pH value of protein extract to the protein isoelectric point to precipitate protein. Extract comprising precipitated protein is cooled to temperature from 0 C to 32 C and protein is separated from extract. Washing out the separated protein is omitted or carried out with minimal amount of water. Invention allows to obtain products with significantly elevated concentration of isoflavones with curative properties in isolated protein. EFFECT: improved preparing method, valuable medicinal properties of product. 18 cl, 8 tbl, 7 ex
