title: Formation Mechanism for Potent Antioxidative o-Dihydroxyisoflavones in Soybeans Fermented with Aspergillus saitoi.
abstract: The formation mechanism for the potent antioxidative o-dihydroxyisoflavones, 8-hydroxydaidzein (8-OHD) and 8-hydroxygenistein (8-OHG), was studied by incubating whole soybeans in a solid culture and a soybean extract in a liquid culture with Aspergillus saitoi. Analyses of changes in the isoflavone analogue content, β-glucosidase activity, and isoflavone hydroxylation ability indicated that 8-OHD and 8-OHG were formed from daidzein and genistein, respectively, by microbial hydroxylation, being respectively liberated from daidzin and genistin by β-glucosidase from A. saitoi during incubation. No selective hydroxylation reaction at the 8-position of daidzein and genistein were apparent during the vegetative stage, but were induced at the stage of sporulation.
authors.affiliation: a Department of Food and Nutrition, Sugiyama Jogakuen University.
authors.forename: H
authors.initials: H
authors.lastname: Esaki
authors.affiliation: a Department of Food and Nutrition, Sugiyama Jogakuen University.
authors.forename: R
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: a Department of Food and Nutrition, Sugiyama Jogakuen University.
authors.forename: H
authors.initials: H
authors.lastname: Onozaki
authors.affiliation: a Department of Food and Nutrition, Sugiyama Jogakuen University.
authors.forename: S
authors.initials: S
authors.lastname: Kawakishi
authors.affiliation: b Department of Applied Biological Sciences, Nagoya University.
authors.forename: T
authors.initials: T
authors.lastname: Osawa
keywords: 8-hydroxydaidzein; 8-hydroxygenistein; Aspergillus saitoi; antioxidant; sporulation