EFFECT OF GRINDING AND EXPERIMENTAL CONDITIONS ON THE MEASUREMENT OF HYDRATION PROPERTIES OF DIETARY-FIBERS

The swelling capacity, the water-binding capacity and the water-holdin g capacity were determined on four fibre sources: wheat bran; pea hull s; sugar-beet; and citrus fibre. Each fibre source was previously grou nd to obtain three different mean particle sizes. Grinding decreased s welling capacity and water-binding capacity of wheat bran, sugar-beet and citrus fibre probably by alteration and collapsing of the fibre ma trix. The water-holding capacity of these fibres was little affected a t equilibrium. Both water-binding and water-holding capacities of pea hulls tended to increase after grinding, probably because of an increa se in surface area and pore volume. In the case of sugar beet fibre, t he experimental parameters such as stirring conditions altered the phy sical structure of the fibres which resulted in a large change in wate r-binding capacity. These results underline the influence of the physi cal structure of the fibre on the hydration properties.