Extraction and Concentration of Isoflavones from Soybean (Glycine max)

Abstract

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.

Keywords:

• concentration
• isoflavones
• liquid-liquid extraction
• response surface methodology
• soybean
• ultrafiltration

ACKNOWLEDGEMENTS

The help rendered by Dr. Umesh Hebbar is gratefully acknowledged. The author Ms. Lakshmi expresses her gratitude and sincere thanks to the Council of Scientific and Industrial Research (CSIR), New Delhi for providing a senior research fellowship.

Notes

*per gram of dry extract.

Yield is the content of total isoflavones in the extract (mg)/content of total isoflavones in feed (mg) × 100.