food tests Flashcards
(8 cards)
What solution is used to test for reducing sugars?
Benedict’s solution.
How do you test for reducing sugars?
Add Benedict’s solution to the sample and heat in a water bath for 5 minutes. A positive result is a colour change from blue to brick-red.
What solution is used to test for starch?
Iodine solution.
How do you test for starch?
Add iodine solution to the food. A positive result is a colour change from orange-brown to blue-black.
What solution is used to test for proteins?
Biuret solution (a mix of sodium hydroxide and copper sulfate).
How do you test for proteins?
Add Biuret solution to the sample and mix. A positive result is a colour change from blue to purple/lilac.
What solution is used to test for lipids?
Ethanol (used in the emulsion test).
How do you test for lipids?
Mix the sample with ethanol and shake
