Page 113 - Pharmd general phytochemistry I-Final2024_LEUCTERS

Disaccharides

A- Reducing Disaccharides
Lactose (Milk sugar)

Occurrence:
 Lactose is a byproduct obtained of whey, which is the portion of milk that is left after

the fat and casein have been removed for the production of butter and cheese.
 Upon the evaporation of whey, lactose crystallizes out.

4-O(B-D-galactopyranosyl) D- glucopyranose
 Lactose is hydrolyzed readily by acid solutions or emulsin to give one molecule of

each of D-glucose and B-D-galactose.
 It is soluble in water and reduces Fehling's solution.
Uses:

1- Diluent in tablets and powders.
2- Nutrient in infants formulas, being more easily digested than sucrose.

Maltose (Malt sugar)

Maltose

4-O-(α-D-glucopyranosyl)-α-D-glucopyranose
Occurrence:
 Maltose is rarely found as such in nature (malt extract).
 It occurs only as a constituent of polysaccharides particularly of starch and dextrins

from which it is liberated as an end product of the action of amylase.

111