Unit 7 Lab Report #1: The Reactions of Gelatin With Pineapple Enzymes in Different Heat Conditions

  Andy Liu
  Honors Biology - A
  Mr. Quick

  ABSTRACT
   For the lab, we tested the combination of strawberry-flavored jell-O with canned and fresh vegetables to see how will the change in enzymes affect their reactions with the protein. Since the canned pineapples have been heated, it will affect the enzyme activities by turning off its active sites. Because of the closed active sites, the substrates will not be able to enter enzymes for reaction. Therefore, the Jell-O would not react with inactive enzymes in canned pineapples, and eventually becomes solid. 

 INTRODUCTION
  The role of enzymes in the digestive system is to accelerate the reactions of substrates and lower the active energy barrier. To achieve that, the enzymes allow the substrate into its active sites. The active sites of the enzymes will act as a template for substrate orientation, stabilize the transition state of the substrates, provide a favorable micro-environment, and directly participate in the catalytic reaction. In the specific situation between pineapples and Jell-Os, the proteases in bromelain, which is a chemical in the pineapple, will break the collagen bonds in Jell-O, and stop the Jell-O from forming a solid state. (Source) However, do different conditions of pineapples affect the resulting form of the Jell-O?

 HYPOTHESIS
  We hypothesized that the Jell-O with canned pineapples and the Jell-O without pineapples will change their states to solid, while the Jell-O with fresh pineapples remains liquid. 

The box cover of Jell-O with instructions

 MATERIALS
1. 3 empty petri dishes
2. A water beaker
3. Strawberry-flavored Jell-O powder (6.6 grams)
4. Canned and fresh pineapples, and each type has 6 pieces in the same size (26 grams for each type)
5. A boiling plate
6. 78.8 ml of water
7. Tapes and markers
8. A stirring stick

 PROCEDURE
 We began the lab by making strawberry-flavored Jell-O:
   At first, we heated 39.4 ml water by using the boiling plate, and we put 6.6 grams Jell-O powder in the beaker. Then we poured the boiling water into the beaker, and we stirred the water with the powder until the powder is completely dissolved. Later, we added another 39.4 ml cold water to the jello, and stirred the jello mix again until the water is fully mixed. 
  After we finished making the Jell-O mix, we put the mix in 3 petri dishes, and each dish should have the same amount of Jell-O. To finish the process, we put 26 grams of fresh pineapples, the independent variable, in one dish, and 26 grams of canned pineapples in another one. We put our names on the petri dishes with tapes and markers, and we kept them in the room for two days until we return to check the result. 

Results of our lab

RESULT
  As a result, the Jell-O dish without pineapples and the Jell-O with canned pineapples have both changed to a solid state. However, the Jell-O dish with fresh pineapples is still in liquid state.

CONCLUSION
  The result of our lab proved our hypothesis correct. The Jell-O with fresh pineapples didn't become solid because the collagen bond in Jell-O or other gelatins will be broken by going the reaction process with digestive enzymes in pineapples. Since the room temperature is comfortable for the pineapple enzymes, the collagen can easily enter the active site and react with them. However, we could have achieved more in this lab by using different fruits or different temperature, and a possible error in the lab would be the limited time to wait for the jell-O to form before we check the result. 

WORKS CITED
  Helmenstine, Anne Marie, Ph.D. "Pineapple and Jell-O." About.com Chemistry. N.p., n.d. Web. 17 Feb.   2014.