Composition and foam properties of whole wheat dough liquor as affected by xylanase and glucose oxidase

Xylanase (XYL) and glucose oxidase (GOX) have been applied to improve the crumb structure of whole wheat buns. However, their effects on the constituents dissolved in the dough liquor (DL), which supposedly contributed to gas cell stabilization and crumb structure, have not been elucidated. In this study, we aimed to unravel the effects of these enzymes on the protein and arabinoxylan contents, DL yields, bulk viscosity, as well as foaming properties. DL was first separated through ultracentrifugation from whole wheat dough prior treated by XYL and GOX. The results indicated that XYL and GOX treatment increased the DL yields. Moreover, while XYL increased the water extractable arabinoxylan content, GOX increased the protein level in the DL. The free sulfhydryl groups of soluble proteins declined significantly in the presence of GOX. Moreover, GOX might have catalyzed the formation of large protein aggregates and protein-polysaccharide complexes. Furthermore, while the foaming capacity of DL increased only in the presence of XYL, the foam stability was increased by both XYL and GOX, especially under heat treatment. The present research might help to understand the mechanism of crumb structure improvement of whole wheat buns by XYL/GOX treatment from the view of their effects on the DL.