Karina Martin
Mr. Quick
A Block
2/16/14
The Effects of Enzyme Bromelain on Collagen (protein) Bonds
ABSTRACT:
The objective of this lab was to observe how fresh pineapple and canned pineapple react when mixed with jello. In other words, my partner and I wanted to see the effects of pineapple enzymes on jello. We designed an experiment where we made three plates of jello, two of which contained either fresh pineapple or canned pineapple. After leaving the three plates of jello alone for a couple of days, we observed that the jello containing fresh pineapple was still in a liquid state. The jello containing canned pineapple, however, became set (jello state), as did the jello mix containing nothing extra (obviously).
INTRODUCTION:
Jello packets usually has a note or warning saying not to add fresh or frozen fruit because the gelatin will not set. This is because many fruits, including pineapple, contain a chemical called bromelain, which can affect the hardening or setting of the jello. Bromelain contains two enzymes that have the capability of breaking down proteins called proteases. Many gelatin, like jello, get their shape/structure from links formed between chains of collagen. Bromelain cuts these chains of collagen and keeps the gelatin from jelling properly (becoming set). Fresh pineapple does this as a defense mechanism. Canned pineapple, on the other hand, is heated during the canning process. This means that the enzymes in bromelain in the pineapple are inactivated once they have been heated to about 158° F (70° Celsius). Therefore, the jello mixed with canned pineapple (or any other canned fruit) will become set.
HYPOTHESIS:
If we fill three plates with jello mix, with fresh pineapple in one and canned pineapple in another, then the only jello not to become set/gel will be the one containing fresh pineapple due to the fact that fresh pineapple has not been heated while canned pineapple has.
MATERIALS:
- 26 grams of fresh and canned pineapple chunks
- 6.6 grams of jello powder
- 3 plates (petri dishes)
- a beaker
- 39.4 grams of hot water
- 39.4 grams of cold water
- tape and marker (for labels)
PROCEDURE:
- Pour 6.6 grams of jello powder into a beaker
- Add 39.4 ml of hot water to jello powder
- Stir the water and powder until dissolved
- Add 39.4 ml of cold water to jello mix
- Stir the jello again
- Pour jello mix into beaker
- Pour equal amount of jello mix from beaker into 3 plates
- Add 26 grams of fresh pineapple chunks into one plate
- Add 26 grams of canned pineapple chunks into another plate
- Leave one plate with only jello
- Wait for results and check next class.
RESULTS:
| PLATES | SET | LIQUID |
| JELLO w/ FRESH PINEAPPLE | NO | YES |
| JELLO w/ CANNED PINEAPPLE | YES | NO |
| JELLO (alone) | YES | NO |
CONCLUSION:
In conclusion, the jello containing fresh pineapple did not become set, while the jello containing canned pineapple did, proving our hypothesis. Therefore, when pineapple still containing bromelain mixes with jello (which contains collagen), the jello will not set properly due to the breaking of collagen bonds. However, when heated pineapple mixes with jello, the jello does set properly due to the reformation of the collagen bonds' shapes and active site. The bromelain is inactivated and the jello can become set. Throughout this experiment, my partner and I kept the plate with only jello constant. Measuring the fruit, water, or jello incorrectly are possible errors that could have occurred along the way. My partner and I also could have done more trials to get more accurate results. We also could have tested other fruits or had the plates of jello and fruit in different temperatures and/or environments.
CITATIONS:
"Pineapple and Jell-O." About.com Chemistry. N.p., n.d. Web. 17 Feb. 2014.
"UCSB Science Line Sqtest." UCSB Science Line Sqtest. N.p., n.d. Web. 17 Feb. 2014.
"Why Can't You Put Pineapple Chunks in Jello?" General Chemistry Online: FAQ: Chemistry of
Everyday Life:. N.p., n.d. Web. 17 Feb. 2014.
No comments:
Post a Comment