Hydrothermal treatments in the development of isoflavone aglycones in soybean (Glycine max (L.) Merrill) grains

Abstract

Studies were carried out to enhance the development of isoflavone aglycones in soybean. Grains of two soybean cultivars, BR 36 and IAS 5, 115 and 278 mg/100g of total isoflavone, respectively, were treated hydrothermalyl at 45, 60 and 85°C for 5, 30 and 60 minutes. Pre-treatments of grains at 60°C for 60 minutes allowed a considerable increase of the isoflavone aglycones. Non-treated grains of BR 36 and IAS 5 showed 1.2 mg/100g of genistein, after hydrothermal treatments, which increased to 12 and 53 mg/100g, in each variety, respectively. At higher temperature (85°C) there was a decrease of the aglycones due to inactivation of β-glycosidases. Malonyl compounds were also reduced at higher temperatures. In processing functional soybean foods, hydrothermal treatments of the soybean grains, as well as high isoflavone content soybean cultivars will enhance development of aglycone forms.