1. Identification of Macromolecules with Indicators
You are What you Eat!

2. Carbohydrates Contain aldehyde/ketone and alcohol groups
Certain mono and disaccharides can be detected due to their aldehyde groups
Some polysaccharides can be detected because of their 3-D structure
Water, soluble, hydrophilic
Can’t be detected by hydroxyl groups
2 tests: Benedict’s and Iodine

3. Color change blue to burnt orange
Benedict’s
Benedict’s reagent + R-C=O  Benedict’s (reduced) + R-C=O
(oxidized) H OH
Sugar gains an oxygen during reaction (oxidized); only reacts on free aldehyde group. Why not ketone?
Color change blue to burnt orange
Safety Note: must heat reaction for 2 minutes

4. Iodine Tests for starches (polysaccharide)
Polymer of glucose in which chains are coiled up in a particular way that they react with the Iodine molecules
Color change: Gold-Brown to a Blue-Black

5. Fats
Hydrophobic molecule consisting of a glycerol molecule joined to 3 fatty acids.
Important functional groups are hydroxyl and carboxyl grps
Long hydrocarbon chains = nonpolar
Tests: Sudan III, Brown Bag or Solubility

6. Sudan III
Depends on the detection of the hydrocarbon groups in the 3 fatty acid tails.
The colored dye, Sudan III (red), and the hydrocarbon groups are both non-polar and stick together in their polar surroundings hydrophobic test (layer or reccish orange on top of water)
This also can be considered a “solubility test” as fats do not mix with the water layer

7. Brown Bag Fats leave a “greasy” mark on the cellulose paper bag
If Sudan III is used in conjunction, the spots show up a salmon-orange color

8. Proteins Polymers of amino acids Carboxyl and amino functional groups
The covalent bond between amino acids is called a “Peptide bond”
Test: Biuret Test

9. Biuret Test Bound amino groups (N-H2) reacts with Biuret
Interaction between copper (II) cations in the Biuret reagent and the N-H in the peptide bonds
Color change= Aqua  Lavendar
Safety Note: Biuret is highly basic! Be careful!

10. Nucleic Acids (DNA and RNA)
Are they in our foods?
How can we test?

11. Why is this lab Important?
What types of information can we get from indicator tests?
How does it relate to society?
To health? To medicine?