ABSTRACT
Dietary fiber (DF) is a mixture of plant carbohydrate polymers: oligosaccharides and polysaccharides (e.g., cellulose, hemicelluloses, β-glucan, pectic substances, gums, resistant starch, inulin, and fructo-oligosaccharides), oligofructose, and the soy bean oligosaccharides raffinose and stachyose. These polymers may be accompanied by lignin and other noncarbohydrate components, for example, polyphenols, waxes, saponins, cutin, phytates, and resistant proteins. Chitosan is an example of a fiber of animal origin, derived from chitin and contained in the exoskeletons of invertebrates, such as the carapaces of crustaceans and insects and also in minor species, such as fungal mycelia. Chitosan is the second most abundant polysaccharide in nature after cellulose. Another definition of dietary fiber indicates focuses on it as a mixture of nondigestible carbohydrates and lignin not absorbed in the human intestine.
