Extraction and Concentration of Isoflavones from Soybean (Glycine max).

The extraction and concentration of isoflavones from defatted
soy flour (DSF) is attempted by leaching, membrane process and
liquid-liquid extraction. The optimized extraction conditions by
response surface methodology (RSM) resulted in an isoflavone content
of 3.2 mg/g of DSF. The extracted isoflavones are processed by
ultrafiltration for preliminary purification resulting in 3.0 mg/g of
DSF, and then concentrated by liquid-liquid extraction with diethyl
ether (4.8 mg/g DSF). The final isoflavone content is 69 mg/g of
dried extract with an overall recovery of 57.5%. The optimization
of extraction conditions resulted in an about 2.5 fold enhancement
of isoflavones and concentration step enriched the isoflavones by
about 8.5 fold compared to initial extract.