Food Tests
Test
|
Tests for
|
Positive Result
|
Method
|
Iodine
|
Starch
|
Turns Blue-Black
|
Add a drop of iodine to food solution
|
Biuret
(CuSO4 + NaOH)
|
Protein
|
Turns Purple-Lavender
|
Add a few drops of copper sulphate (CuSO4) and sodium hydroxide (NaOH) to food solution
|
Benedict’s Solution
|
Sugar
|
With heat turns Brick-Red precipitate
|
Add a few drops of Benedict’s to food solution and heat gently of a bunsen
|
Ethanol Emulsion
|
Fats
|
White Emulsion
|
Add 2ml of ethanol to food solution and shake/mix, then add 2ml of water to solution and shake/mix
|
DCPIP
|
Vitamin C
|
Turns Colourless
|
Add a few drops of DCPIP to food solution and shake/mix then wait (NB: will turn pinky due to the presence of acid - false positive)
|
