Name ____________________ Hr _____
McMush Lab
Simple Sugars
We can test for the presence of simple sugars by using Benedict’s solution. If Benedict’s solution is added to a solution that
contains simple sugars, the solution will turn orange after being heated in a microwave. The solution will turn a bright orange
color if a large amount of sugar is present. If smaller amounts of sugar are present the change will be less noticeable.
Procedure:
1. Pour water into a test tube and label it “1”
2. Pour McMush into a test tube and label it “2”
3. Pour sugar (glucose) solution into a test tube and label it “3”
4. Put 5 drops of Benedict’s solution into all of the test tubes.
5. Gently swirl each test tube.
6.
Record the color of each test tube below:
1. Water: __________
7.
8.
2. McMush: __________
3. Sugar: __________
Place all test tubes in the microwave for 30-45 seconds.
Observe color changes and record your results below.
1. Water: __________
2. McMush: __________
3. Sugar: __________
9. In which of these three test tubes did you detect the presence of simple sugars? Place a “+” next to the test tubes that had sugars
present and a “-” next to the test tubes that did not have sugars present.
1. Water: __________
2. McMush: __________
3. Sugar: __________
10. In which of the three components of our McMush solution (fries, cheeseburger, pop) would you expect to find the highest
amount of sugars? Explain.
11. Use the test tube brush to clean the test tubes before continuing.
Starch
We can test for the presence of starch by using Lugol’s Iodine solution. If Lugol’s Iodine solution is added to a solution that
contains starch, the solution will turn a dark greenish-black color. The solution will turn a dark black color if a large amount of
starch is present. If smaller amounts of starch are present the change will be less noticeable.
Procedure:
1.
2.
3.
4.
Pour water into a test tube and label it “1”
Pour McMush into a test tube and label it “2”
Pour starch solution into a test tube and label it “3”
Record the color of each solution below.
1. Water: __________
2. McMush: __________
3. Starch: __________
5. Put 5 drops of Lugol’s Iodine solution into all of the test tubes.
6. Gently swirl each test tube.
Name ____________________ Hr _____
7.
Observe color changes and record the color of each solution below.
1. Water: __________
8.
2. McMush: __________
3. Starch: __________
In which of these three test tubes did you detect the presence of starch? Place a “+” next to the test tubes that had starch present
and a “-” next to the test tubes that did not have starch present.
1. Water: __________
2. McMush: __________
3. Starch: __________
9. In which of the three components of our McMush solution (fries, cheeseburger, pop) would you expect to find the highest
amount of starch? Explain.
10. Use the test tube brush to clean the test tubes before continuing.
Lipids / Fats:
Lipids are important because they are used to make up part of the cell membrane of the cells in your body. The amount of fat
permitted in ground beef is regulated by law: 30% maximum for regular ground beef and 15% maximum for lean ground beef. The
amount of fat in french fries is not regulated.
The presence of fats in a substance can be detected by using unglazed paper towel. Fats leave an oily, translucent smear when
touched to the paper.
1.
2.
3.
4.
5.
6.
Tear off a small piece of paper towel. On the corners of the paper towel write the numbers 1,2, and 3.
Place one drop of water on the area marked #1.
Place one drop of your McMush on the area marked #2.
Place one drop of oil on the area marked #3.
Set the paper towel aside for approximately 15 minutes and complete the protein section of the lab. After the paper towel
has had time to dry answer the questions below.
Hold the paper towel up to the light and look at the 3 spots.
7. In which of these 3 spots did you detect the presence of fats? Place a “+” next to the locations on your paper towel that had fats
present and a “-” next to the test tubes that did not have proteins present.
1. Water: __________
8.
2. McMush: __________
3. Oil: __________
In which of the three components of our McMush solution (fries, cheeseburger, pop) would you expect to find the highest
amount of fats? Explain.
Proteins
We can test for the presence of proteins by using Biuret’s reagent. If Biuret’s reagent is added to a solution that contains protein,
the solution will turn purple. The solution will turn bright purple if a large amount of protein is present. If smaller amounts of
protein are present the change will be less noticeable.
1.
2.
3.
Pour water into a test tube and label it “1”
Pour McMush into a test tube and label it “2”
Pour egg albumin (protein) solution into a test tube and label it “3”
Name ____________________ Hr _____
4.
Record the color of each solution below.
1. Water: __________
2. McMush: __________
3. Egg Protein: __________
5. Put 5 drops of Biuret’s solution to all of the test tubes.
6. Gently swirl each test tube.
7.
Observe color changes and record the color of each solution below.
1. Water: __________
2. McMush: __________
3. Egg Protein: __________
8. In which of the three test tubes did you detect the presence of proteins? Place a “+” next to the test tubes that had proteins
present and a “-” next to the test tubes that did not have proteins present.
1. Water: __________
2. McMush: __________
3. Egg Protein: __________
9. In which of the three components of our McMush solution (fries, cheeseburger, pop) would you expect to find the highest amount
of proteins? Explain.
10. Use the test tube brush to clean the test tubes before continuing.
11. Look at your paper towel from the lipids/fats test. Record your results.
**Clean – up your station. Spray with bleach solution and have your teacher sign you out of
lab_______
Sit down and answer the questions below.
Summary Questions: Fill in the following table
Reagent
Lugol’s iodine
Benedicts
Biurets
Tests For
Original Color
+ Test Color
1.
In the McMush solution, what foods provided the main sources of protein? __________________________
2.
In the McMush solution, what foods provided the main sources of sugars? __________________________
3.
In the McMush solution, what foods provided the main sources of starches? _________________________
4.
In the McMush solution, what foods provided the main sources of lipids?
5.
Would we expect water to test “+” for any of the nutrients? ________
6.
If you had a “+” water test what should you do? _______________________________________________
__________________________
___________________________________________________________________________________
Name ____________________ Hr _____
7.
What is the purpose of the test tube with water? _____________________________________________
8.
A certain food was sweet. A student tested it and the results came out “-” for Benedicts and “-“ for Lugol’s.
Explain the results.
9.
Water runs off the waxy surface of a leaf. Which test would show “+” for the leaf’s surface?
10. Two foods were tested with Benedict’s. One turned yellow and the other turned dark orange. Explain the results.
11. Mushrooms were tested for all of the macromolecules tested in this lab (Carbohydrates: sugars and starch, Protein,
Lipids). All tests came out negative. What do these results tell us about mushrooms?