Transcript Food Tests - Chemistry Resources for IB, AP, Alevel, GCSE

Food Tests
Grade8
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 this
substance 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.
Food tests
These are some of the most common food tests:
Substance tested
Test
Result
Starch
Iodine
Turns blue-black
Sugars
Proteins
Benedicts solutio Turns red
n
Biuret test
Turns purple
Fats
Emulsion test
Turns cloudy whit
e