How do the results of the iodine test indicate that hydrolysis of starch occurred

Blue color of iodine-starch complex is disappear upon hysrolysis

Explanation:

Starch:

Starch is a polysaccharide

it is energy reservoir.

starch is made of monomers of glucose in a chain form.

The simplest form of starch is linear polymer amylose.

Iodine Test:

In this test iodine solution added to the solution to check the presence of starch.

Iodine solution = elemental iodine + KI

Result of Iodine Test:

when the iodine solution (I₃⁻) is added to a solution it show two types of result.

if the starch is present this I₃⁻ form a complex with amylose chain of starch and impart a dark blue color.

if starch is not present then the color will be orange or yellow.

Hydrolysis of Starch:

Hydrolysis of starch is carried out by an enzyme, this enzyme break down the starch into simpler sugar molecule.

So,

When the hydrolysis of starch occur the starch convert to glucose. Then the blue color of starch and iodine complex formed during iodine test is disappear that will be the indication of hydrolysis of starch.