Table 1.
The structures, sources, and physicochemical characteristics of common SDFs and their effects on the gut microbiota.
| Type | Structure | Source | Viscosity | Fermentability | Changes Related to the Gut Microbiota |
|---|---|---|---|---|---|
| FOS | Sucrose combines with 1 to 3 fructoses linked by a β-glycosidic bond | Vegetables, fruits, produced by enzyme-catalyzed synthesis | No | Yes | Increased α-diversity, Increased Bifidobacteria and Lactobacilli [41] |
| GOS | Galactose or glucose combines with 1 to 7 galactoses linked by a β-glycosidic bond | Milk, produced by enzyme-catalyzed synthesis | No | Yes | Increased β-diversity, Increased Lactobacillaceae and Lachnospiraceae, Decreased Ruminococcaceae [42] |
| Inulin | D-fructose linked by a β-glycosidic bond with glucose at the end | Vegetables, fruits, grains | DP < 9: No DP ≥ 9: Yes |
Yes | Increased β-diversity, Increased Prevotellaceae [43] Increased α-diversity, Increased Bifidobacteria, Decreased Desulfovibrio [44] |
| β-glucan | High polymer composed of D-glucose linked by a β-glycosidic bond | Grains | Yes | Yes | Increased Bifidobacteria and Lactobacilli, Decreased Enterobacteriaceae [45] |
| Pectins | Polysaccharides with complex structures containing D-galacturonic acid, rhamnose, arabinose, and galactose | Vegetables, fruits, beans | Yes | Yes | Increased Bifidobacteria, Lactobacilli, and Faecalibaculum spp. [46] Increased β-diversity, Inhibited Citrobacter rodentium [47] |
| Gums | Polysaccharides with complex structures containing mannose, galactose, glucose, and D-galacturonic acid | Leguminous plants, nuts, seaweeds | Yes | Yes | Increased Bifidobacteria and Lactobacilli [48] Inhibited Clostridium histolyticum [49] |
| Psyllium | Mixture of polysaccharides consisting of arabinose, xylose, galactose, rhamnose, and D-galacturonic acid | Plantago ovate | Yes | No | No |
| Methylcellulose | Long-chain substituted cellulose, in which about 30% of the hydroxyl groups exist in the form of methoxyl | Synthesized | Yes | No | No |
| RS-4 | Chemically modified starch, such as acetyl starch, hydroxypropyl starch, heat-modified starch, and phosphorylated starch | Synthesized | Yes | Yes | Increased Bacteroides, Bifidobacteria, Lactobacilli, Coprococcus, and Allobaculum [50,51,52] |
FOS: fructo-oligosaccharides, GOS: galacto-oligosaccharides, DP: degree of polymerization, RS-4: type IV resistant starch.