Effect of soaking and fermentation on content of phenolic compounds of soybean (Glycine max cv. Merit) and mung beans (Vigna radiata [L] Wilczek)

Abstract

Mung beans (Vigna radiata [L] Wilczek) purchased from a Spanish company as “green soybeans”, showed a different phenolic composition than yellow soybeans (Glycine max cv. Merit). Isoflavones were predominant in yellow soybeans, whereas they were completely absent in the green seeds on which flavanones were predominant. In order to enhance their health benefits, both types of bean were subjected to technological processes, such as soaking and fermentation. Soaking increased malonyl glucoside isoflavone extraction in yellow beans and produced an increase in apigenin derivatives in the green beans. Lactobacillus plantarum CECT 748 T fermentation produced an increase in the bioactivity of both beans since a conversion of glycosylated isoflavones into bioactive aglycones and an increase of the bioactive vitexin was observed in yellow and green beans, respectively. In spite of potential consumer confusion, since soybean and “green soybean” are different legumes, the health benefits of both beans were enhanced by lactic fermentation.

• Bioactive compounds
• consumer confusion
• flavonoids
• isoflavones
• vitexin

Acknowledgements

We are grateful to M. V. Santamaría and J. M. Barcenilla

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article. J. M. Landete and M. Dueñas are recipients of “Ramón y Cajal” contracts from the MINECO.

This work was supported by grants RM2012-00004 (Instituto Nacional de Investigación Agraria y Alimentaría), AGL2008-01052, AGL2011-22745, Consolider INGENIO 2010 CSD2007-00063 FUN-C-FOOD (MINECO) y S2009/AGR-1469 (ALIBIRD) (Comunidad de Madrid).