Enzyme Pineapple Lab
BACKGROUND: The enzymes in some tropical fruits can break down protein. For
example meat tenderizers have the enzyme, papain that breaks down some of the fiber.
We use it to soften up a tough piece of meat. The papain comes from the papaya fruit.
Pineapple has a digestive enzyme called bromelin.
MATERIALS:
Four test tubes
Frozen pineapple
Test tube rack
Fresh pineapple
Hot gelatin
Canned pineapple
Ice water bath
PROCEDURE:
1. Label the test tubes 1-4
2. Fill each test tube no more that half full with liquid gelatin
3. Place fresh pineapple into tube 1
4. Place canned pineapple into tube 2
5. Place frozen pineapple into tube 3
6. Note that tube 4 only contains gelatin
7. Mix the contents of the tubes by rolling them upright between the palms of your
hands
8. Place all four test tubes into the ice water bath
9. Every few minutes check to see if the gelatin is setting in the tubes. When test
tube 4 has gelled firmly you can remove all the tubes and compare the
consistencies
10. Record your observations
DISCUSSION QUESTIONS:
1. Why did test tube #4 contain only gelatin?
2. What could account for the different results in the tubes?
3. How could the canning process change bromelin?
4. What could you do to fresh pineapple, when making gelatin with pineapple that would allow the gelatin
to gel?
5. Design an experiment to find a temperature at which a meat tenderizer works the best?
GRAPH THE FOLLOWING ENZYME CURVES:
Rate of reaction (minutes)
0
1
2
3
4
5
6
pH of Pepsin
0 and 5
1.1 and 4.9
1.3 and 4.7
1.5 and 4.5
2 and 4
3
pH of Trypsin
4 and 9
4.2 and 8.8
4.5 and 8.5
4.8 and 8.2
5 and 8
5.8 and 7.2
6.7
Your graph shows the rate of enzyme activity in relation to pH for two enzymes. Both enzymes break
down molecules in food taken into the human body, but the enzymes act in a series. Pepsin breaks down
large molecules while trypsin acts on the fragments produced by pepsin, breaking them down even smaller.
Answer the following question regarding the graph:
1. The liquid in the stomach has a pH of about 2. Which of the two enzymes would
be active in the stomach?
2. The liquid in the small intestine has a pH of about 8. Which of the two enzymes
would be active in the small intestine?
3. Consider the data on the relationship between pH and enzyme activity. Do
enzymes typically function only at a specific pH, or can they function at a range
of pH values?
4. Can pepsin and trypsin function in the same environment? Explain.