Food TestsGrade8

Test for starch

• Collect the food sample (liquid) in a test tube.

• Add few drops of iodine solution.(yellowish brown)

• If the colour changes from yellowish brown to blue black then thissubstance contains STARCH

Test for fat

• Collect the food sample (liquid) in a test tube.

• Add ethanol and shake well.

• Add water.

• If a cloudy mixture appears then the food sample contains FAT.

Test for protein

• Collect the food sample (liquid) in a test tube.

• Add 5 drops of copper sulphate.

• Add 5 drops of sodium hydroxide.

• If the colour changes from blue to purple then the food sample contains PROTIEN.

Test for sugar (glucose)

• Collect the food sample (liquid) in a test tube.

• Add few drops of Benedict’s solution.

• Place the test tube in a boiling water bath.

• If the colour changes from blue to green to orange to a red deposit, then the sample contains SUGAR (GLUCOSE)

• The colour change depends on the concentration of sugar in the sample.

Turns cloudy white

Emulsion testFats

Turns purpleBiuret testProteins

Turns redBenedicts solution

Sugars

Turns blue-blackIodineStarch

ResultTestSubstance tested

Food tests

These are some of the most common food tests: