Biology Topic Practice

Iodine Test for Starch

Iodine solution is a quick and effective way to identify the presence of starch in food.

What is the positive result for starch?

What is Iodine Test for Starch?

"The iodine test is a chemical procedure used to detect the presence of starch in a substance."

Question 1

What colour change shows starch is present when iodine solution is added?

Question 2

Which result would show protein is present?

Question 3

A food sample gives a brick-red precipitate with Benedict’s solution after heating. What does this show?

Question 4

Which observation is a positive result for the emulsion test for lipids?

Testing for Starch

Add a few drops of iodine solution to the sample.

If starch is present, it turns from orange/brown to blue-black.

Commonly used on potato, bread, or leaf samples.

Exam Tip

Iodine can be used to track the progress of starch digestion by amylase.

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