Isoflavonoids in Soy and Soy-Containing Foods

Soy is exceptionally rich in isoflavonoids, which are linked to various health benefits. The aim of the research was to determine the content of isoflavonoids in soy and some soy-containing foods. The research featured the Sentyabrinka soy variety developed at the All-Russian Research Institute of Soy, as well as such novel soy-containing foods as soy-and-pumpkin drinks and desserts, e.g. soy-and-pumpkin okara crackers. The content of isoflavonoids was determined by high performance liquid chromatography using a Millichrom F-02 chromatograph. The total content of isoflavonoids was 221.10 mg/100 g in the soy beans, 44.50 mg/100 g – in the soy-and-pumpkin dessert, 36.15 mg/100 g – in the soy-and-pumpkin jelly, 30.80 mg/100 g – in the cracker with soy-and-pumpkin okara, 21.19 mg/100 g – in the protein drink, 12.72 mg/100 g – in the vitamin drink. The samples were tested for such isoflavonoids as genistein, diadzein (major), and glycetein (minor), which took the form of aglycones, glycosides (genistin, diadzin, and glycitein), and malonyl derivatives of glycosides. The highest content of malonyl diadzin and malonyl genistin was registered both in the soy beans and the soy-containing foods: from 42.56 in the crackers to 67.50% in the soy beans. The content of isoflavonoids in the soy-containing food products depended on the formulation and production technology, namely, on the amount of soy. A daily intake of 200 g of soy-and-pumpkin drink or 100 g of soy-containing dessert could provide the daily intake of isoflavonoids, which makes these products beneficial for human health.