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

  1. Place small samples of different foods on a paper plate or paper towel.
  2. Predict which foods you think will contain starch.
  3. Add one drop of iodine to each food sample.
  4. Observe color changes: blue/purple/black indicates starch is present, brown/yellow means little or no starch.
  5. If color is hard to see, mix the sample with a little water first, then add iodine.

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?