Food Test for Starch

Starch is a carbohydrate, specifically a polymer of glucose. Carbohydrates provide the body with energy. Starch is found in food like potatoes, cassava, maize, and wheat.

Learning Objectives

To carry out test for starch in a given food sample.

Materials

Iodine solution*, water, empty plastic bottle, droppers*, heat source, test tubes*, and a food sample containing starch such as maize our.

Hazards and Safety

Iodine solution is harmful to swallow.

Preparation Procedure

1. Prepare a food sample solution by either saving the water that remains from boiling pasta or potatoes, or by mixing 2 teaspoons of maize our into about a litre of water, then heat up to dissolve and reduce the white appearance of the liquid, which may give students the answer without having to perform the experiment.

Activity Procedure

1. Place 2 mL of sample solution into a test tube.

2. Add 3 drops of iodine solution to the test tube and record what hap-pens.

Results and Conclusions

When iodine is added, the food sample will change to a blue-black colour. This indicates that the food sample contains starch.

Clean Up Procedure

1. Unused iodine solution should be stored in a labeled reagent bottle.

2. No special disposal is required for waste from this activity.