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The insoluble fiber, consisting primarily of cellulose, retains water and gas in the intestinal lumen, increasing the mass faecal and producing effects attributable to a volumetric and mechanical (stimulates the speed of transit): it interferes so negligible on the viscosity of luminary content and is poorly fermentability

The most important characteristic of fibre is the ability to "tie the 'water' means the soluble fiber, being made up of polysaccharides low molecular weight and polar constituents, has a high capacity for hydration; form into the mass suitable gelled (ie a solution viscose)..

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