Structural modifications to water-soluble wheat bran arabinoxylan through milling and extrusion

Feruloylated arabinoxylan (AX) is one of the most predominant dietary fiber in cereal grains. In recent decades, soluble AX has gained interest, as a result of its well-established health benefits. Apart from enzymatic degradation during cereal storage, food processing causes AX degradation. These reactions lead to structural modifications and influence both the AX functionalities and its health promoting effects. The aim of this study was to investigate the structural modifications and related property changes of health promoting water-extractable (WE) wheat bran AX through grain milling and extrusion. Multi-detector HPSEC revealed a correlation between Mw, conformational changes and the related viscosity behaviour depending on the processing type. Processing caused molecular degradation of insoluble high Mw AX, which increased the solubility significantly. Moreover, extrusion leaded to a more heterogenic AX fine structure. The detailed characterization of processed dietary fiber may help to facilitate the optimized incorporation of AX in health-promoting foods.