demonstrations:testing_for_starch_in_food
Testing for Starch in Food
Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★★☆ Some safety precautions required to perform safely
Categories: Food Science and Nutrition
Alternative titles: Iodine Starch Test
Summary
This activity uses iodine as an indicator to test different foods for starch. When iodine comes in contact with starch, it produces a dark blue or purple-black color, while foods without starch remain brownish-yellow.
Procedure
- Place small samples of different foods on a paper plate or paper towel.
- Predict which foods you think will contain starch.
- Add one drop of iodine to each food sample.
- Observe color changes: blue/purple/black indicates starch is present, brown/yellow means little or no starch.
- If color is hard to see, mix the sample with a little water first, then add iodine.
Links
Test for starch | Food chemistry | Chemistry - KClassScienceChannel:
📄 Testing for Starch in Food - Sciencecityed: https://www.instructables.com/Testing-for-Starch-in-Food/?fbclid=IwAR1basA2mt87JkCJtDxQtL61cn3BPGPa5nw1q88A9me375DsQ2mlGrZ48Z4
Variations
- Test a wider range of foods such as rice, pasta, bananas, and beans.
- Compare raw vs. cooked samples of the same food.
- Try testing processed foods like cereals or chips.
Safety Precautions
- Wear gloves and protect clothing—iodine stains.
- Do not ingest iodine or tested samples.
- Dispose of food and iodine safely after testing.
Questions to Consider
- Why do some foods contain starch while others do not? (Plants store energy as starch, while foods like fruit store sugars.)
- Why does iodine change color in the presence of starch? (It reacts with amylose, a component of starch, forming a blue-black complex.)
- How does cooking affect starch detection in foods?