1H NMR Fingerprinting of Soybean Extracts, with Emphasis on Identification and Quantification of Isoflavones

1H NMR spectra were recorded of methanolic extracts of seven soybean varieties (Glycine max.), cultivated using traditional and organic farming techniques. It was possible to identify signals belonging to the groups of amino acids, carbohydrates, organic acids and aromatic substances in the spectra. In the aromatic zone, the isoflavone signals were of particular interest: genistein, daidzein, genistin, daidzin, malonylgenistin, acetylgenistin, malonyldaidzin signals were assigned and these compounds were quantified, resulting in accordance with published data, and further demonstrating the potential of the NMR technique in food science.