Simple Extraction and Rapid Quantitative Analysis of Isoflavones in Soybean Seeds

A simple extraction and rapid HPLC method, suitable to separate and quantify the isoflavonoids in soybean seeds, are proposed and discussed. The method has been applied to the separation and quantification of seed isoflavonoids in five naturally grown soy cultivars; the total amount of isoflavones ranged from 1.83 g kg−1 to 11.88 g kg−1 of fresh weight. The detection limits (200 μg/kg−1), evaluated for genistein and daidzein, are presented together with a list of the soy polyphenols analysed by HPLC-DAD and HPLC-MS.