Biological Molecules (Excluding Enzymes)

Question 1

What is the test for reducing sugars?

Reducing sugars = all monosaccharides + disaccharides (Except Sucrose)

Answer 1

• Add benedicts solution to the food sample
• Heat in a boiling bath for 2 minutes
• If positive, it will turn brick red

Question 2

What is the test for protein?

Answer 2

• Add biurets solution to the food sample
• If positive, it will turn purple (from blue)

Question 3

What is the test for starch?

Answer 3

• Add iodine to the food sample
• If positive, it will turn to blue-black

Question 4

What is the test for lipids?

Answer 4

• Add ethanol to the food sampleto dissolve the lipids
• Add water
• If positive, a white and cloudy emulsion will form