Bioactive action of beta-glucosidase enzyme of Bifidobacterium longum upon isoflavone glucosides present in soymilk

MARAZZA, J.A.; NAZARENO, M.A.; SAVOY DE GIORI, G.; GARRO, M.S.

INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2013 vol. 48 p. 2480 - 2489

0950-5423

Bioconversion of isoflavone-glucosides and antioxidant activity by probiotic strain (Bifidobacterium longum) during soymilk fermentation was investigated, as well as partial characterization of the produced enzyme beta-glucosidase. The enzyme has higher affinity for genistin than for other substrates assayed. Maximum activity occurred at 42ºC and at pH 6.0; keeping 70-80% of activity for 60 days stored at low temperatures. B. longum grew well in soymilk (8.26 log CFU ml- 1 and pH of 3.9 at 24 h) and were produced good quantities of organic acids. High hydrolysis degree of isoflavone-glucosides (81.2%) was observed at 24 h. Enhancements in bioactivity were assessed in fermented soymilk by monitoring the radical scavenging activity, antioxidant activity and DNA protective action. The use of probiotic Bifidobacterium strain as beta-glucosidase producer increased bioactive isoflavone content and demonstrated that this enzyme plays a key role in the bioavailability of soymilk isoflavones, reducing the bioconvertion time compared to other studies.