Test for Starch

Edexcel AS-level BiologyBiological MoleculesLesson 8 of 25

Starch is detected with iodine solution, which is iodine dissolved in potassium iodide solution.

Method:
1. Add a few drops of iodine solution to the sample (a solution, a suspension, or a solid such as a slice of potato).
2. Observe the colour at room temperature. No heating is needed.

Result: if starch is present the colour changes from orange-brown to blue-black. If there is no starch, it stays orange-brown.

Key terms in this lesson

amylase

An enzyme that hydrolyses the glycosidic bonds in starch, producing maltose.

More in Biological Molecules

• Disaccharides
• Test for Sugars
• Polysaccharides
• Starch
• Glycogen
• Cellulose
• The Nature of Lipids
• Fatty Acids and Glycerol

All 25 lessons in Biological Molecules · All Edexcel AS-level Biology topics