Concentration of soybean isoflavones by nanofiltration and the effects of thermal treatments on the concentrate.

An investigation was performed on the profile and the content of isoflavones in the concentrate of aqueous Defatted Soy Flour (DSF) extract obtained by nanofiltration. The effect of thermal treatments on these isoflavones was also evaluated according to a Central Composite Design (CCD 2k) with varying temperatures (70 to 90 °C) and times (15 to 45 minutes). Through nanofiltration it was possible to concentrate B-glucosides and malonyl glucosides (p 0.05). The thermal treatments applied on the concentrate showed that the malonyl glucosides were influenced by temperature (p 0.05) of aglycone or total isoflavones