Oligosaccharides:
Carbonhydrates which upon hydrolysis form 2 to 9 molecules of monosaccharides or simple sugars are called Oligosaccharides.
Explaintion:
Therefore, depending upon the number of monosaccharides units they produce on hydrolysis, they are further classified as dissaccharides, trisaccharides etc. Prefixes di,tri, tera, penta etc. Indicate the number of monosaccharide units, they produce on hydrolysis. They are white crystalline solids. They have sweet taste and are insoluble in water.
Example:
C120H22O11 + H2O → 4 C-IIH3C-IIH2OH + 4CIVO2
This is an oxidation-reduction (redox) reaction:
8 C0 + 16 e- → 8 C-II
(reduction)
4 C0 - 16 e- → 4 CIV
(oxidation)
Polysaccharides:
Carbohydrates which upon hydrolysis form 100 to 1000 units of dimple sugars are called polysaccharides. Starch and cellulose are polysaccharides. They are amorphous solids. They are tasteless and insoluble in water. They are non-reducing in nature.