Structure-function relationships for corn bran arabinoxylans

Fiber incorporation in foods has, to date, been approached largely in an empirical manner, with emphasis on modifying process conditions and formulation and fiber characteristics to obtain an acceptable product. There is a lack of fundamental studies relating fiber functionality during processing with its structural characteristics. In this study, we have investigated the theological properties; such as solution shear viscosity and extensional viscosity, and some structural features of four corn bran arabinoxylan preparations. The solution shear viscosity of the fibers was influenced by the molecular weight and size of the molecules. The extensional viscosity of doughs containing the fibers was affected by the degree of branching, and differences in extensional viscosity have been explained on the basis of differences in branching as observed using multi-angle laser light scattering. Clear relationships between solution viscosity and molecular weight, and extensional viscosity and degree of branching were established for the fibers. Fundamental studies such as this one will aid in building a strong science-based approach to fiber incorporation in food by improving understanding of how structure of fiber molecules affects their functionality in food systems and how the structure can be modified to improve functionality. (C) 2010 Elsevier Ltd. All rights reserved.