Effect of Grinding and Experimental Conditions on the Measurement of Hydration Properties of Dietary Fibres

Abstract The swelling capacity, the water-binding capacity and the water-holding capacity were determined on four fibre sources: wheat bran; pea hulls; sugar-beet; and citrus fibre. Each fibre source was previously ground to obtain three different mean particle sizes. Grinding decreased swelling capacity and water-binding capacity of wheat bran, sugar-beet and citrus fibre probably by alteration and collapsing of the fibre matrix. The water-holding capacity of these fibres was little affected at equilibrium. Both water-binding and water-holding capacities of pea hulls tended to increase after grinding, probably because of an increase in surface area and pore volume. In the case of sugar beet fibre, the experimental parameters such as stirring conditions altered the physical structure of the fibres which resulted in a large change in water-binding capacity. These results underline the influence of the physical structure of the fibre on the hydration properties.