The Reaction of Collagen to Fruits’ Enzymes

Abstract:

In this lab, we observed the how collagen reacts to fruits’ enzymes, specifically bromelain. In order to see this reaction we places 39.4 grams of boiled water and 39.4 grams of cold water and added 6.6 grams of Jell-O gelatin we stirred it for 5 minutes then placed equal amounts of the gelatin into four petri dishes. Than we placed 7.9 grams of fresh cut pineapple into one of the dishes, 7.9 grams of fresh cut kiwi into one of the dishes, and 7.9 grams of fresh cut mango. We did not place fruit into one of the dishes so that it can be the control. Then we covered the dishes and put them into the refrigerator for three days. After three days, we checked the dishes, those containing pineapple and kiwi did not set and were still liquid. The mango and the control were the only two petri dishes to set properly.

 

Question:

Do the enzymes in the different fresh fruits have the same reaction to collagen?

 

Background:

Pineapple as well as many other fruits contains the chemical bromelain which contains two proteases that are enzymes capable of digesting proteins. Jell-O and other gelatins get their structure from protein called collagen. So when pineapple or similar fruits are added the enzyme, bromelain, breaks down the proteins and does not allow the gelatin to set. This does not apply when we use canned pineapple because when heat above 158°F the enzyme becomes inactive. When an enzyme is heated past a certain degree the shape of the substrate changes and it prevents it from digesting proteins because the proteins no longer fit in the substrate. The same applies to pH levels.

 

Hypothesis:

If fruits containing bromelain are placed into gelatin then they will not set unlike the control where we did not add any fruits. And fruits not containing bromelain will set properly like the control.

 

Materials:

·         Hot water

·         Cold water

·         Jell-O gelatin

·         4 petri dishes

·         Labels

·         Pineapple

·         Stirring rod

·         Kiwi

·         Mango

·         Graduated cylinder

·         Refrigerator

 

Procedure:

1.      Boil water

2.      Measure 39.4 grams of the water then add 6.6 grams of gelatin

3.      Stir for 5 minutes until the gelatin is dissolved

4.      Add 39.4 grams of cold water

5.      Place 19.7 grams of the solution into each of the 4 petri dishes

6.      Add 7.9 grams of fresh cut pineapple to a petri dish and label the cover

7.      Add 7.9 grams of fresh cut kiwi to a petri dish and label the cover

8.      Add 7.9 grams of fresh cut mango to a petri dish and label the cover

9.      Do not add fruit to the fourth petri dish, so that it can be the control

10.  Place the labeled covers on each dish and put them into the refrigerator

11.  Check your results in 3 days and record the data

Results:

 

                         

The upper dish is the mango dish                                                  The dish above is the pineapple dish

The lower dish is the kiwi dish

 

The above picture is the control dish

Conclusions:

My hypothesis that fruits containing bromelain would not set in gelatin is correct. Also, my other hypothesis that fruits not containing bromelain would set same as the control which was just plain gelatin. The only two petri dishes that set properly were the ones containing mango and nothing at all. This shows that mangos do not contain bromealin. The petri dishes containing pineapple and kiwi did not set which shows that they do contain bromelain. The two constants of this lab were equal amounts of gelatin and water in each dish and refrigerating them for the same amount of time at the same temperature. Two possible errors are jot placing cold water into the gelatin; this would not allow the gelatin to set, and checking on the results too early and not allowing them enough time to set.

Citations:

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