title: Optimizing dough proofing conditions to enhance isoflavone aglycones in soy bread.
abstract: Native beta-glucosidase activity in soy bread can convert isoflavone glucosides to aglycones during proofing, and this study determined the time-temperature dependence of this process. Samples were taken every hour for 4 h during proofing at 22, 32, and 48 degrees C to determine beta-glucosidase activity and isoflavone profiles of the dough. After 1-2 h, the beta-glucosidase activity increased 43-84% achieving a plateau value at 22 degrees C but declining when proofed beyond 2 h at 32 degrees C and 48 degrees C. Large increases in aglycones and corresponding decreases in the simple glucosides were observed during proofing. The level of malonyl-glucosides decreased 3-15%, and acetyl-glucosides were fairly constant. The two higher temperatures drove more rapid conversion: 70-73% of simple glucosides in 2-4 h. The extent of conversion in the early proofing periods corresponded to beta-glucosidase activity. The optimum time-temperature protocol was 2 h at 48 degrees C resulting in a rapid, high conversion.
authors.affiliation: Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Court, Columbus, Ohio 43210, USA.
authors.forename: Ken M
authors.initials: KM
authors.lastname: Riedl
authors.forename: Yu Chu
authors.initials: YC
authors.lastname: Zhang
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Schwartz
authors.forename: Yael
authors.initials: Y
authors.lastname: Vodovotz
mesh_terms: D001939:Bread; D005511:Food Handling / Q000379:methods*; D005960:Glucosides / Q000032:analysis; D007529:Isoflavones / Q000032:analysis*; D045730:Soy Foods / Q000032:analysis*; D013696:Temperature; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D005960:Glucosides; D007529:Isoflavones; D001617:beta-Glucosidase