Testing starch in foods

By : Via Noviani

The Presence Of Starch

Starch : An odorless tasteless white substance occuring widely in plant tissue and obtained chiefly from cereals and potatoes. It is polysaccharide that functions as a carbohydrate store and is an important constituent of the human diet.

Equipments :                                                        Materials :
                                                         
- Evaporating dish                                               - Iodine solution  I₂
- Test tube                                                         - Grape Juice
- Test tube rack                                                  - Banana
- Fume hood                                                      - Potato
- Filter funnel
- Knife
- Pestle/mortar
- Glass rod
- Pipette
- Tongs
- Bunsen burner
- Breaker


Steps :
1. Divide the banana into two ,add 3 drops of Iodine solution
2. Divide the potato into two ,add 3 drops of Iodine solution
3. Put the grape juice into test tube ,add 3 drops of Iodine solution
4. Do all those things inside the fume hood
5. You can see the result

In order to perform this project, we must use Iodine solution as a reagent for starch. One drop of this solution on any sample can detect starch by changing the color of the tested area to dark blue.We will be using the following samples :

SAMPLE	NORMAL COLOR	ADDED BY IODINE SOLUTION
Banana	Cream	Black
Potato	Cream	Black
Grape Juice	Purple	No changes

( This is an assignment for my Biology A Level  )

Starch Indicator : A blue-black color indicates the presence of starch. The darker the color ,the greater starch it's contain.