Processing Affects the Physicochemical Properties of Fiber from Wheat and Flax in Ready-to-Eat (RTE) Flaked Cereal

Abstract

Fiber from wheat and flax is mostly insoluble, making addition in high amounts to a food difficult without adversely affecting product attributes. One approach to increasing the level of these fibers in food is to hydrolyze fiber to more soluble forms through processing. This study was designed to evaluate the impact of a steam pressure cooking process on physicochemical properties of ready-to-eat (RTE) cereal with 17.7% added unhydrolyzed flax fiber (a combination of arabinoxylans, rhamnogalacturonans, and pectins) or 15.4% added hydrolyzed wheat fiber (a purified arabinoxylan extract). Peak molecular weights of unhydrolyzed and hydrolyzed fibers were ∼2.9 × 106 and ∼800 g/mol, respectively, with a ∼400-fold higher viscosity for unhydrolyzed fiber. Molecular weight of the unhydrolyzed fiber ingredient was reduced to approximately the molecular weight of the hydrolyzed fiber as a result of the low-shear steam pressure cooking process used, and consistent with molecular weight results, there was only a two...