Influence of malting procedure on the isoflavonoid content of soybeans

The goal of this study was to analyse, whether malting technique (consisting of seed hydration, germination and drying) can be used to modify concentration of various isoflavonoids in soybean seeds. Seeds of three soybean varieties were germinated by different lengths of time (from 24 to 120 h) and dried by two different methods, typically used to produce so-called ‘light’ and ‘caramel’ malts. It was determined, that malting decreases concentration of 7-O-β-D-glucosides such as daidzin, genisitin and glycitin, while at the same time increasing concentration of aglycones (daidzein, genistein and glycitein). Increasing time of the germination period increased concentration of aglycones. ‘Caramel’ type malts were characterised with higher concentration of most of the isoflavonoids (daidzin, daidzein, genistin, genistein and glycitein) than ‘light’ type malts. Results of this study suggest that soybean malts can be an interesting substrate in the production of various food products with increased aglycone content.