Detalle de: Development of soy beverages enriched in O-desmethylangolesin and 6-hydroxy-O-desmethylangolesin by engineered lactic acid bacteria

The main isoflavones in food are daidzin and genistin, which must be deglycosylated into daidzein and genistein to increase their biological activity and bioavailability. Later, daidzein can be transformed into O-desmethylangolensin (O-DMA) and/or equol, while genistein can originate 6-hydroxy-desmethylangolensin (6-OH-O-DMA) and/or 5-hydroxy-equol. The objective was to understand the metabolism of O-DMA and 6-OH-O-DMA by lactic acid bacteria (LAB) to increase the concentration of both compounds in fermented beverages due to their ability to inhibit the proliferation of cancer cells and improve the antioxidant activity. Assays with different engineered LAB strains showed that O-DMA and 6-OH-O-DMA are produced by LAB mainly from daidzein and genistein, respectively, by fission of the C-ring. O-DMA and 6-OH-O-DMA producing LAB harbouring pNZ:TuR.gly913, or the food grade vector pLEB590.gly913, both with the glucosidase gen gly913, increased the production of O-DMA and 6-OH-O-DMA in addition to daidzein and genistein. Moreover, the combination of O-DMA and 6-OH-O-DMA producing LAB with potential probiotic properties, and a bifidobacteria strain with high deglycosydase activity, allowed the development of probiotic soy beverages enriched in O-DMA, 6-OH-O-DMA, daidzein and genistein. Soy beverages enriched in O-DMA, 6-OH-O-DMA, daidzein and genistein would be of value for the development of functional foods.