Outline the classification of carbohydrates giving example for each.(OR) How are carbohydrates classified?

Explanation

Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketones. The carbohydrates may be summarised as below.

(i) Sugar : They are sweet crystalline substance and soluble in water.
(a) Monosaccharides : They are polyhydroxy aldehydes (or) polyhydroxy ketones.
Aldoses - Carbohydrates containing aldehyde group. Eg: Glucose
Ketoses - Carbohydrates containing ketone group. Eg: Fructose.
(b) Oligosaccharides : They are sugars that yield two to ten monosaccharide molecules on hydrolysis.
Disaccharides : They are sugars which on hydrolysis give two molecules of same or different monosaccharides. Eg: Sucrose, maltose.
`underset("Sucrose")(C_(12)H_(22))O_(11)+H_(2)Orarrunderset("Glucose")(C_(6)H_(12)O_(6))+underset("Fructose")(C_(6)H_(12)O_(6))`
Trisaccharidcs: They are sugars which gives there molecucules of monosaccharides on hydrolysis Eg: Raffinose.
`underset("Raffinose")(C_(18)H_(32)O_(16))+2H_(2)Orarrunderset("Galactose")(C_(6)H_(12)O_(6))+underset("Glucose")(C_(6)H_(12)O_(6))+underset("Fructose")(C_(6)H_(12)O_(6))`
(ii) Non-sugars (or) Polysaccharides:
They are non-sugars which involve a large number of monosaccharide units linked to each other by oxide bridges. These bridges are called glycosidic linkages. Eg: starch, cellulose.
`underset("Starch")(C_6H_10O_5)+nH_(2)Ooverset(H^(+))rarrunderset("Glucose")(nC_(6)H_(12)O_(6))`