Enhanced estrogenic effects of biotransformed soy extracts

[Display omitted] •Soymilk biotransformation by tannase is an effective biotechnological process.•Isoflavone glycosides were biotransformed into bioactive forms.•It is possible to produce equol using only enzymatic bioprocess.•Biotransformed soy extracts could be an alternative to hormone replacement therapy. Soy isoflavones have been associated with several beneficial effects to human health including estrogenic action. Due to the risks associated with pharmaceutical hormone replacement therapy, soy extracts rich in isoflavones and metabolites appear as a safe alternative for menopausal women. This study aimed to improve the process conditions for biotransformation of soymilk polyphenols by tannase to obtain higher amounts of isoflavone aglycones and metabolites such as equol. The estrogenic potential of the extracts was evaluated in in vitro assays. The results showed that the aglycones increased 36–46 times after reaction with tannase and proved that it is possible to produce equol in soymilk using an enzymatic bioprocess, without gut microbial intervention. Moreover, the soymilk biotransformed by tannase presented higher estrogenic action in the MCF-7 BUS cell line assay, making it a promising nutraceutical with possible effects in the attenuation or treatment of menopause symptoms.