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 |
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 |
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 |