Changes in structure and solubility of wheat arabinoxylan during the breadmaking process

Abstract

Arabinoxylans (AXs) are the major nonstarch polysaccharides of wheat. AX functionality is essential for many wheat flour-based products, including pan bread. Regarding the quality of pan bread, the primary focus has been on protein content and quality. However, AX may play an important role in the end-product quality of pan bread. To understand the role that AX plays in the quality of pan bread, the chemical and structural changes of AX during bread preparation and dough fermentation were studied. Flour from three wheat varieties (Bolles, Glenn, and Elgin-ND) was used, and samples were taken at seven stages during the breadmaking process. Changes in AX solubility, AX substitution rate, and fine structure of AX were evaluated. The solubility of AX increased significantly (P < 0.05) during mixing and fermentation, but was significantly (P < 0.05) lower in the bread. The degree of xylose substitution also changed significantly (P < 0.05) during mixing and/or fermentation. There were also changes to the substitution pattern that indicated structural changes to AX during the fermentation process. Flour properties, such as xylanase activity and the initial structural and functional properties of AX, could impact changes to AX occurring during the fermentation and baking process. The flour samples used in this study had similar protein contents, but differed in dough properties and AX structure. Overall, there were substantial changes in the AX of wheat flour during bread processing. The changes to AX could have a great impact on dough functionality and the end-product quality of pan bread.