Food Tests

Question 1

How is the starch test performed?

Answer 1

Place starch powder in the depession on a spotting tile.
Add a few drops of iodine solution
Poitive result: Blue/black
Negative result: Brown

Question 2

How is the glucose test performed?

Answer 2

Add equal amounts of test solution and Benedicts solution into a test tube, and combine.
Heat the mixture in a water bath.
If a brick-red precipitate is formed, glucose is present in the test solution.

Question 3

How is the biuret (protein) test performed?

Answer 3

Add a food sample of choice into a test tube.
Add 2ml of sodium hydroxide and 5-6 drops of copper sulfate to it.
Shake gently to mix, and allow to stand for 4-5 minutes.
If a bluish-violet colour appears, protin is present.