Table 1.
The classification of dietary fibers according to the composition, properties and main sources [13,14,15,16].
| Poly-/Oligo-Saccharides Class | Sources | Main Units | References |
|---|---|---|---|
| Non-Starch Polysaccharides, MU ≥ 10 | |||
| Cellulose * | Cereals, pulses—outer layers, root and leafy vegetables, legumes, pears and apples | Glucose monomers | [17] |
| Hemicellulose ** | Cereal bran and whole grains (starchy endosperm and aleurone layer), vegetable and fruit cell walls | D-xylose, D-mannose, D-galactose and L-arabinose | [14] |
| Mannans and heteromannans | Date, green coffee bean seeds and aloe vera Grain legumes (endosperm) Iris seeds and lily bulbs Norway spruce wood pulp |
Mannans *, galactomannans #, glucomannans # and galactoglucomannans | [16] |
| Pectins # | Apple and citrus peel (and other fruits), cabbage, whole grains, beetroot and grain legumes | Arabinose, rhamnose, galactose sugars and galacturonic acids | [14] |
| Gums | Xanthan gum * Alginates ** Agar-agar ** Carrageenan ** |
Pentose and hexoze monomers | [18] |
| Mucilages # | Aloe vera, Cactus, Okra, Hibiscus | Main glycoproteins | [16] |
| Inulin # and fructans | Jerusalem artichoke, Chicory root, onion and cereal grains | fructofuranosyl residues | [15] |
| Non-Digestible (resistant) oligosaccharides, MU = 3–9 | |||
| α-galactosides ** | Chickpea, bean, lentil, etc. | Raffinose, stachyose, verbascose | [15] |
| β-fructo-oligosaccharides ** | Polymers resulted from polysaccharides hydrolysis (inulin and lactose hydrolysis produce FOS and, respectively, GOS). | β-Fructo- (FOS), α-galacto- (GOS), β-galacto- (TOS), xylo- (XOS), arabino-xylo- (AXOS) oligosaccharides |
[15] |
| Resistant dextrins ** | cereal-based vegetable milk, baked goods, dairy products and granola bars | Poly-D-glucose | [15] |
| Polydextrose ** | Cakes, candies, mixes and frozen desserts and beverages | Poly-D-glucose | [15] |
| Resistant Starches * (RS), MU ≥ 10 | |||
| RS type 1 | Grains and legumes (whole or partially milled) | physically inaccessible starch | [15] |
| RS type 2 | High-amylose starches, green bananas | granular starches | [15] |
| RS type 3 | Cooled starches in cooked starchy foods and enzyme-debranched starches | gelatinized and retrograded starches | [19] |
| RS type 4 | chemically modified (mainly cross-linked starches) | [15] | |
| Associated Substances Non-carbohydrates | |||
| Lignin * | Fruits, particularly strawberries and peaches | Coumaryl, coniferyl and sinapyl alcohols (aromatic alcohols) | [17] |
| Waxes * | Wax is present in rice bran, seed and seed hulls of sunflower | Long alkyl chains | [20] |
| Chitins * | Fungus’ cell walls, lobster, crab and shrimp exoskeletons and insects | N-acetylglucosamine | [15] |
| Phytates/Phytic acid # | Plant seeds, mainly in legumes, peanuts, cereals and oilseeds and generally found in almost all plant-based foods | - | [21] |
* Insoluble, ** Slightly soluble, # Soluble; and MU = monomeric units.