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

MARAZZA, J.; 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 characterisation of the produced enzyme b-glucosidase. The enzyme has higher affinity for genistin than for other substrates assayed. Maximum activity occurred at 42 °C and at pH 6.0; keeping 70?80% of activity for 60 days stored at low temperatures. Bifidobacterium longum grew well in soymilk (8.26 log CFU Ml_1 and pH of 3.9 at 24 h) and were produced in 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 b-glucosidase producer increased bioactive isoflavone content and demonstrated that this enzyme plays a key role in the bioavailability of soymilk isoflavones, reducing the bioconversion time compared to other studies.