Classification of carbohydrates

 

MONOSACCHARIDES

Number of Carbon Atoms	Aldose Form	Keto Form
3	Glyceraldehyde	Dihydroxyacetone
4	Erythrose	Erythrulose
5	Ribose	Ribulose
5	Arabinose	Xylulose
6	Glucose	Fructose
6	Mannose	Fructose
6	Galactose	Tagatose
7	Sedoheptulose	Erythrose

Disaccharides

Disaccharide	Type	Components	Type and Position of Bond	Chemical Properties	Found Where in Nature
Sucrose	Non-reducing	Glucose + Fructose	α,β-1,2-glycosidic bond	Hydrolyzed by sucrase enzyme	Sugar cane, sugar beets
Lactose	Reducing	Glucose + Galactose	β-1,4-glycosidic bond	Hydrolyzed by lactase enzyme	Milk and dairy products
Maltose	Reducing	Glucose + Glucose	α-1,4-glycosidic bond	Hydrolyzed by maltase enzyme	Germinating grains, malt
Cellobiose	Reducing	Glucose + Glucose	β-1,4-glycosidic bond	Hydrolyzed by cellulase enzyme	Cell walls of plants
Trehalose	Non-reducing	Glucose + Glucose	α,α-1,1-glycosidic bond	Resistant to hydrolysis	Insects, fungi, bacteria
Isomaltose	Reducing	Glucose + Glucose	α-1,6-glycosidic bond	Hydrolyzed by isomaltase enzyme	Honey, caramelization products

Oligosaccharides 

Oligosaccharide	Classification	Components	Type and Position of Bonds	Chemical Properties
Raffinose	Trisaccharide	Galactose + Glucose + Fructose	α-1,6-glycosidic bond (Gal-Glc), β-2,1-glycosidic bond (Glc-Fru)	Hydrolyzed by α-galactosidase enzyme
Stachyose	Tetrasaccharide	Galactose + Galactose + Glucose + Fructose	α-1,6-glycosidic bond (Gal-Gal), α-1,6-glycosidic bond (Gal-Glc), β-2,1-glycosidic bond (Glc-Fru)	Hydrolyzed by α-galactosidase enzyme
Maltotriose	Trisaccharide	Glucose + Glucose + Glucose	α-1,4-glycosidic bonds	Hydrolyzed by α-amylase enzyme
Maltotetraose	Tetrasaccharide	Glucose + Glucose + Glucose + Glucose	α-1,4-glycosidic bonds	Hydrolyzed by α-amylase enzyme
Xylobiose	Disaccharide	Xylose + Xylose	β-1,4-glycosidic bond	Hydrolyzed by β-xylosidase enzyme
Lactulose	Disaccharide	Galactose + Fructose	β-1,4-glycosidic bond	Not readily hydrolyzed by human enzymes

Polysaccharides

Polysaccharide	Classification	Components	Type and Position of Bonds	Chemical Properties
Starch	Homopolysaccharide	Amylose (α-D-glucose) + Amylopectin (α-D-glucose)	α-1,4-glycosidic bonds (Amylose), α-1,4 and α-1,6-glycosidic bonds (Amylopectin)	Hydrolyzed by amylase enzymes
Cellulose	Homopolysaccharide	β-D-glucose	β-1,4-glycosidic bonds	Not hydrolyzed by human enzymes
Glycogen	Homopolysaccharide	α-D-glucose	α-1,4 and α-1,6-glycosidic bonds	Hydrolyzed by glycogen phosphorylase and α-amylase
Chitin	Homopolysaccharide	β-D-N-acetylglucosamine	β-1,4-glycosidic bonds	Partially hydrolyzed by chitinase enzymes
Agarose	Heteropolysaccharide	Agarobiose (β-D-galactose + α-L-galactose) + Agarose (β-D-galactose)	β-1,3-glycosidic bonds (Agarobiose), β-1,4-glycosidic bonds (Agarose)	Not readily hydrolyzed by human enzymes
Pectin	Heteropolysaccharide	D-galacturonic acid + Rhamnose + Arabinose + Galactose	α-1,4-glycosidic bonds (Homogalacturonan), α-1,4 and α-1,2-glycosidic bonds (Rhamnogalacturonan)	Partially hydrolyzed by pectinase enzymes