Supercritical carbon dioxide extraction of daidzein and genistein from soybean products

The extractibility of isoflavones by supercritical carbon dioxide was studied by extracting synthetically produced daidzein (1), genistein (2), formononetin (3) and biochanin A (4), Supercritical fluid carbon dioxide (SFCO2) modified with 20% ethanol at 50 degrees C and 600 atmospheres pressure extracted nearly 93% of these isoflavones in 60 min, Daidzein and genistein were extracted by SFCO, and quantified by high performance liquid chromatography in the extracts of soybean food products, mise, tofu, soy meal and soy flour; the amounts of 1 and 2 (expressed in mu g/g dry weight) in these foods were found to be 42, 61; 20, 20; 40, 8 and 10, 5, respectively, This Is the first report of supercritical carbon dioxide extraction of 1 and 2 from soy products.