Starch forms a helical structure that traps certain molecules and gives a blue colour. Which of the following tests is used to confirm the presence of starch?
Correct answer: A. Iodine test
- A. Iodine test
- B. Benedict's test
- C. Biuret test
- D. Sudan III test
Explanation
Among the listed tests, only the iodine test detects starch by producing a blue-black colour. This occurs because iodine molecules fit into the helical structure of amylose, forming a coloured complex. The other tests-Benedict's for sugars, Biuret for proteins, and Sudan III for lipids-are specific to different types of biomolecules and do not detect starch.
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