Isoflavone extraction from okara using water as extractant.

Lena Jankowiak, Nikolaos Kantzas, Remko Boom, Atze Jan van der Goot

Index: Food Chem. 160 , 371-8, (2014)

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Abstract

We here report on the use of water as a 'green' extraction solvent for the isolation of isoflavones from okara, a by-product of soymilk production. At a low liquid-to-solid ratio of 20 to 1 and 20 °C, 47% of the isoflavones that can be extracted with 70% aqueous ethanol were extracted. The malonyl-glucosides were fully recovered with a ratio of 20 to 1, while β-glucosides were recovered with an increased liquid-to-solid ratio of 40 to 1. The extraction of aglycones was better at higher ratios, but leveled off before reaching a 100% yield. Temperature hardly affected the total amount of isoflavones. At a 20 to 1 ratio, 20 °C, and pH 10, there was no significant difference (p>0.05) between isoflavone extraction in water and in 70% aqueous ethanol. The results suggest that water may be used as a green alternative for separation of isoflavones from okara.Copyright © 2014 Elsevier Ltd. All rights reserved.