Table 5.

 Classification of fibers based on 4 characteristics

Dietary fiber	Functional fiber
Cellulose	Psyllium
Hemicelluloses	Fructooligosaccharides
Pectins	Polydextrose
Lignin
Soluble fibers	Insoluble fibers
β-Glucans	Cellulose
Gums	Lignin
Psyllium	Some hemicelluloses
Pectin	Primary sources: wheat bran, some vegetables, some fruits, legumes
Primary sources: oats, barley, citrus fruits
Fermentable fiber	Nonfermentable fibers
Pectins	Cellulose
β-Glucans	Lignin
Inulin and oligofructose	Primary sources: cereal fibers rich in cellulose, mature root vegetables
Primary sources: oats, barley, fruits, vegetables, grains, legumes
Viscous fibers	Nonviscous fibers
Pectins	Cellulose
β-Glucans	Lignin
Some gums (e.g., guar gum)	Hydrolyzed guar gum
Psyllium