Page 94 - PG 504-theoretical notes-phyto-1-2024-2025..
P. 94
Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)
Main differences between Amylose and Amylopectin:
No. Item. Amylose. Amylopectin.
1 Solubility in H 2O More soluble Less soluble.
2 Reaction with I 2 Deep blue complex Blue-violet or purple
3 % in starch. About 25% About 75%
4 Structure Linear chain Branched chain.
5 -Amylase Only maltose Dextrin 60%+
“exoamylase” maltose 40%
6 -Amylase Mixture of Branched and unbranched
“endoamylase” Maltose + glucose oligosaccharide having -
1,6 linkage
7 Mineral acids Glucose. Glucose.
8 Viscosity of sol. in H 2O Less viscous More viscous.
Acid Hydrolysis of starch
Hydrolysis of starch by mineral acids ultimately produces glucose in nearly
quantitative yields. The course of the reaction is followed by iodine reactions
which changes successively from bluish black to purple to red to no reaction.
Properties:
▪ White powder or masses, with starchy taste.
▪ Insoluble in cold water.
▪ By boiling with water, a colloidal sol is formed, which, if concentrated, sets
on cooling into gel.
75
