JELLO ENZYME LAB
HAVE YOU EVER NOTICE THE WARNING ON A JELLO PACKAGE NOT TO USE FRESH OR FROZEN PINEAPPLE?
TODAY WE ARE GOING TO INVESTIGATE WHY.
Background: The enzymes in some tropical fruits can break down protein. For example meat tenderizers have the enzyme, papain,
which breaks down fiber. We use it to soften up a tough piece of meat. Pineapple belongs to a group of plants called Bromeliads.
Kiwi, papaya, and figs are other types of Bromeliads. Bromeliads produce bromelin, an enzyme which is responsible for the
breakdown of collagen. Gelatin is made from a collagen, a protein which comes from the joints of animals. Gelatin may be dissolved
hot water. As the dissolved gelatin mixture cools, the collagen forms into a matrix that traps the water; as a result, the mixture turns
into the jiggling semi-solid mass that is jello.
Hypothesis:
Using the background information and your knowledge of enzymes, write a hypothesis for this lab.
Materials:
Four petri dishes
Gelatin squares
Fresh pineapple
Frozen pineapple
Canned pineapple
Procedure:
1. Get 4 cubes of gelatin and place in petri dishes.
2. Label the dishes 1 – 4.
3. Do not place anything but gelatin in dish 1.
4. Place a piece of fresh pineapple on dish 2, frozen pineapple in dish 3, and canned pineapple in dish 4. Make an immediate
observation. Be sure that each piece is dry when placed on gelatin.
5. Observe the experiment for 30 minutes, make observations every 5 minutes.
6. After 30, clean up your area by putting the dishes with gelatin and pineapple in the trash.
7. Write a conclusion for this lab. Be sure to include:
- Was your hypothesis correct? Why/why not?
- How could you make this experiment better?
- What other factors could you test in this experiment?
- What did you learn?
Data/Results:
First Obs
5 min
10 min
15 min
20 min
Dish 1
(Gelatin)
Dish 2
(Fresh)
Dish 3
(Frozen)
Dish 4
(Canned)
Discussion Questions:
1. Name 3 constants you used in your experiment.
2. What was your independent variable?
3. What was your dependent variable?
4. Why did dish 1 contain gelatin only?
5. What could account for the different results in the dishes?
6. How could the canning process change bromelin?
7. What could you do to the fresh pineapple that would allow the gelatin to become firm?
25 min
30 min