the WHCs among these FRFs (2.37–3.20 ml/g) were comparable but lower than the WHC of cellulose (3.81 ml/g). The comparable WHCs could be explained by the similarities in the FRFs compositions (Table 3), number and nature of the water-binding sites, and structure. As compared to cellulose, the lower WHCs of the FRFs might be partly attributed to their higher densities as well as the fewer water-binding components, due to the presence of impurities and lignin. Table 4 reveals that the FRFs and cellulose have comparable OHCs (2.07–3.72 g/g), which were relatively greater than those of some orange byproduct fibres (0.9–1.3 g/g). In general, the physicochemical properties, such as bulk density, OHC and WHC among different fibres were correlated with their particular chemical and physical structures as well as the preparation methods. In Table 4, the cation-exchange capacities of the FRFs (35.3–50.3 meq/kg) were significantly greater than that of the cellulose (22.7 meq/
kg). As the cation-exchange capacity is related to the uronic acid content of a fibre, the stronger ion binding capacity of the
FRFs relative to cellulose might be attributed to the presence of uronic acids (3.04–3.61 g/100 g FRF) (Table 3). As described by Furda (1990), fibres of higher cation-exchange capacity could entrap, destabilize and disintegrate the lipid emulsion, consequently decreasing the diffusion and absorption of lipids and cholesterol in the small intestine.