Lab - Jell-O & Enzymes



Name ______________________________________ Period __________ Date ___________

Pre-Lab: Jell-O & Enzymes

BACKGROUND:

If you have ever made Jell-O by cooking the powder that comes in a box, you may have noticed the warning on the instructions that tell you not to add fresh or frozen pineapple to the gelatin. Have you ever wondered why?

In this lab, you will be investigating what is really happening when you add pineapple to gelatin. You know enough about enzymes now to figure this out.

First, you need to know a little background about gelatin… and it may be more than you ever wanted to know. Do you know what Jell-O is really made out of? Are you ready?

That sweet colorful treat is actually made out of hides, bones, and inedible connective tissue from animals butchered for meat. Yup!

All gelatin (including those made for photographic and laboratory use, as well as for desserts) is made out of discarded animal parts – the tough parts: bone and skin. And all these tough parts are made of proteins. In fact, the extracted gelatin is a protein. So why do you think gelatin gets thick and jelly-like when you cook it? (We’ll come back to that later.)

Gelatin can be extracted from any kind of animal, but cows are most common. If your Mom or Dad have ever made a batch of chicken soup from scratch, you’ve probably seen how it gets stiff and Jell-O like after it sits in the fridge… that’s because boiling the chicken in water extracts the gelatin from the carcass (bones & cartilage), just like a miniature version of the commercial gelatin factories!

Commercial gelatin making starts by grinding up bones. The crushed bones are then soaked in a strong base (high pH) to soften them, and then passed through progressively stronger acid (low pH) solutions, until the end result isn’t recognizable as bones at all! Then the whole mess is boiled for hours to extract the gelatin… and this part really makes a stink! Finally, the gelatin layer is skimmed off the boiling pot, and dried into a powder. With added sugar, flavorings, and artificial color, it’s ready to become a jiggly dessert!

And now that you know what Jell-O is made from, why don’t you put some on the table tonight? Your guests will be delighted when you share your new knowledge with them in the middle of a luscious spoonful of dessert!

Made from bone… made from protein… so it must be tough stuff! So why can’t you put fresh pineapple in it?

Let’s learn a bit about pineapple. The pineapple plant is a monocot, or grass-like plant, that belongs to the bromeliad family. It is thought to have originated in Brazil. In the 1950s, pineapple became the United State’s second most important fruit and Hawaii led the world in both quantity and quality of pineapples. However, times have changed and now all canned pineapple comes from overseas, largely from the Philippines.

As with some other tropical fruits, the pineapple fruit contains an enzyme that breaks down, or digests, protein. This protease (protein-digesting) enzyme is pineapple is called bromelain, which is extracted and sold in such products as Schilling’s Meat Tenderizer. Papaya, another tropical fruit, also contains an enzyme, called papain, which digests protein. It can be found in Accent Meat Tenderizer.

PRE-LAB QUESTIONS: (You may need to refer to your class notes to answer these questions)

1. Chemically speaking, what is gelatin made of (is it a carbohydrate, a protein, or a lipid)?

Gelatin is made out of hides, bones, and inedible connective tissue from animals. Gelatin is a protein.

2. What are enzymes and what do they do?

Enzymes are proteins and they speed up the process.

3. What enzyme is found in pineapple?

Bromelain is the enzyme found in a pineapple.

4. How do meat tenderizers work?

Meat tenderizers work by digesting proteins.

5. What does it mean for a protein to be denatured and how can they become denatured?

When they become denatured if the temperature and pH then the active site with change shape and the enzyme won’t work.

PROCEDURE:

In this lab, you will test the effect of pineapple juice (both fresh and canned) on gelatin. The goal is to understand what is actually going on in the pineapple-gelatin mix at the chemical level as well as understanding what affects the function of enzymes.

1. You will be given four test tubes. Label the four test tubes as follows: control, fresh pineapple juice, heated fresh pineapple juice and canned pineapple.

2. Put 5 mL of each juice in all test tubes except the one you labeled the control.

3. Have Mr. Stallard pour a15 mL of Jell-O gelatin, prepared according to the instructions on the package, into each test tube.

4. Place your Jell-O in the ice for at least thirty minutes.

5. Write your predictions in the table below and answer pre-lab questions.

DATA TABLE:

|Fruit Added to Jell-O |Predicted Effect on Gelatin |Observed Effect on Gelatin |

|Control (water) | |Jell-O |

| | | |

| |I think that the water will turn into Jell-O. | |

|Fresh Pineapple Juice | |Didn’t Jell |

| | | |

| |I think it will turn into Jell-O because of the | |

| |natural sugars in it. | |

|Canned Pineapple | |No Jell |

| | | |

| |Canned pineapple might turn into Jell-O but I | |

| |don’t think it will. | |

| |I don’t think that the heated fresh pineapple will|Jelled |

| |turn into Jell-O. | |

|Heat Fresh Pineapple Juice | | |

Conclusion – On a separate sheet of paper, in complete sentences; explain what you learned from this lab and how it relates to enzymes. DO NOT tell me what you did…that is in the lab procedures and I already know what you did. I want to know what you learned and how it relates to enzymes.

Today during the Jell-O and Enzymes lab I learned that gelatin found in Jell-O is made out of hides, bones, and inedible connective tissue from animals. All of the tough parts of the discarded animal is protein used by the body. I learned that you can get gelatin from multiple animals but cows are the most common. Gelatin is extracted from the bones and cartilage in your body which causes the stiffening in Jell-O. Commercial gelatin grinds up the bones, then the bones are soaked in pH to soften them, it’s then boiled for hours, which extracts the gelatin that’s then powdered and added with sugar, flavors, and color to create Jell-O. I find this very disgusting because my mom use to make me eat Jell-O when I was younger, which let me to not liking it now and after finding out and learning all this information to how it’s made I will definitely not eat it again. Pineapple contains an enzyme called bromelain which is a protein-digesting enzyme which I think causes the gelatin to not jell when mixed with Jell-O.

Water: The water easily jelled because there was nothing added or naturally in water to stop the gelatin from processing. Water doesn’t have a protein in it that needs breaking down so therefore to me that’s why water will always turn into Jell-O easily.

Fresh Pineapple Juice: I learned that due to the bromelain found in pineapples this stopped the gelatin to not work properly. Gelatin has protein which helps create the Jell-O but pineapples have bromelain which is a protein-digesting enzyme. Meaning that the bromelain is digesting all the protein in the gelatin causing the chemical reaction to not work.

Canned pineapple: I think that the canned pineapple didn’t jell because it’s processed, which to me means that most of the nutrients in the fresh pineapple and all the natural enzymes and everything in it is no longer as effective as it would be if it was fresh.

Heated Fresh Pineapple Juice: I really don’t know how the heated fresh pineapple juice jelled. I have an idea that it jelled because it’s still fresh, which means it has all the nutrients and enzymes in it. I think that it might have jelled because since it’s heated it might have burned out the bromelain from the pineapple allowing the gelatin to work.

After learning everything about enzymes, gelatin, and bromelain that the pineapple contains, it all relates to enzymes because enzymes are proteins that speed up the chemical reaction. Gelatin speeds up the process of creating Jell-O because of the protein in it.

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