Carbohydrates, proteins, fats, vitamins, and other nutrients provide your body with energy and provide the raw
materials necessary to carry on life activities. These compounds are present in the plants and animals you use as food. In
this lab, you will test for specific compounds and then determine if these are in a fast food value meal in sufficient
quantities.

Materials:
Benedict’s solution: tests for sugar (carbohydrates)
Biuret solution: tests for protein
Lugol’s iodine solution: tests for starch (complex carbohydrates)
Sudan III solution: tests for lipids
Pre-Lab Questions
1. What are Biomolecules?
2. List the four biomolecules and provide examples of foods that contain them.
3. What is a chemical indicator?
4. For this lab, which are the chemical indicators you will be using and what is their function?
5. Which types of biomolecules do you predict that you will find in a potato, orange juice, almonds, eggs, salmon
and milk? Explain your prediction.
Food Substance Prediction Explanation
Potato
Orange Juice
Nuts
Eggs
Salmon
Milk
6. How are monomers and polymers different?
7. What are the monomers for each of these macromolecules?
a) Carbohydrates: b) Nucleic Acids:
c) Proteins: d) Lipids (fats):
8. Circle any of the following compounds that would be classified as carbohydrates.
a) Amino acids b) Fructose c) Maltose d) Glucose
e) Starch f) Hemoglobin g) Lactose
9. What’s the purpose of the Food Lab?
10. Read the instructions below. What will you do in Part I? Why?
11. What will you do in Part II? Why?
Part I: Testing of Known Substances: Go online for this part!
You will learn how to test for each of these organic molecules by clicking on the
boxes shown on the left. Complete each of the tests for carbohydrates, proteins
and fats. Write your results in the data table below.
Part II: Test Different Foods: Go online for this part!
When you have finished Part I, you will click on the foods button – shown on the left, to test for the
presence of organic compounds that are found in various common foods. Write your results in the data
table given below.
2
Lab Results
Part I: Testing of Carbohydrates, Proteins, and Fats (Lipids):
a) What substance was used for control? Why?
Food Substance Reagent test How was the test performed? Describe the Color Change
Protein Biuret solution
Simple Sugar Benedict’s solution
Starch Lugol’s Iodine
Lipid Sudan IV
Part II: Testing of Food:
Food Substance Reagent test Color Change Positive Results (Y/N)
Protein Biuret solution
Potatoes
Orange Juice
Nuts
Eggs
Salmon
Milk
Simple Sugar Benedict’s solution
Potatoes
Orange Juice
Nuts
Eggs
Salmon
Milk
Starch Lugol’s Iodine
Potatoes
Orange Juice
Nuts
Eggs
Salmon
Milk
Lipid Sudan IV
Potatoes
Orange Juice
Nuts
Eggs
Salmon
Milk
Answer these questions briefly but completely! Work on your own! DO NOT DISCUSS THESE QUESTIONS!
1. What are the macromolecules from which we get energy?
2. Summarize what you did today, describe what you did. Try to provide enough detail that someone who was not
in class would understand what you did, e.g., why did we need to run the first set of tests before we analyzed
the food?
3. What did you find? (Describe your results for each individual test and what it says about various foods). Which
foods are healthy? Explain what we did and didn’t learn from these tests.