Using Jell-o and Fruit to Demonstrate Enzymatic Activity
Materials
- 1 package of gelatin – any brand or flavor (If you cannot use a cow or pig-based gelatin for any reason, try using a vegan gelatin based on agar-agar or carrageenan.)
- 3 Styrofoam or plastic cups
- Small amount of fresh pineapple, kiwi, papaya, mango, or figs (must be fresh)
- Canned pineapple, fruit cocktail, or boiled (for at least 5 minutes) pineapple, kiwi, papaya, mango or figs
Procedure
- Prepare for the lab by filling out the table in the Background section (following the Procedure section).
- Prepare the gelatin as directed on the package.
- After preparing the gelatin, pour equal amounts into your three cups.
- Label cup 1 as control. Do not add anything to the cup.
- Label cup 2 fresh fruit and add several chunks of the fresh fruit.
- Label cup 3 canned fruit, and add several chunks of canned pineapple, several spoonfuls of fruit cocktail, or several pieces of boiled fruit.
- Complete your Hypothesis on the next page.
- Place the cups in the refrigerator and leave until the gelatin in the control cup has set.
- Remove cups from the refrigerator.
- Get a piece of paper and write your name and UAG student ID on it. Place the paper next to the cups. Then take a picture of the cups with the paper clearly showing.
- Complete the Data Table on the next page, insert or paste your picture in the Evidence section, and answer the questions.
Background
To prepare for the lab, fill out the following table. The questions you are to answer are in the left column. Do a search either in your reading materials or on the internet to answer the questions. In the column Source, write down or provide a link to the source that provided the answer. In the Quote column, copy and paste what the source says that answers the question. In the Your Paraphrase column, write the answer to the question in your own words. You will probably only need only one or two sentences for each answer.
| Question | Source | Quote | Your Paraphrase |
| What is the main ingredient in gelatin? | |||
| What is a protease, and what does it do? | |||
| What fruits contain protease? | |||
| What happens to an enzyme when it is heated to a very high temperature? |
Hypothesis
Do you think that the gelatin in all the cups will be set? Why or why not?
Data Table
| Materials | Specific Material Used |
| Gelatin used (animal, vegetarian – agar, carrageenan, etc.) | (Type in here what gelatin you used: animal or vegetarian. If vegetarian, what was the gelatin using? Agar, carrageenan, etc.) |
| Fresh fruit | (Type in here what fresh fruit you used.) |
| Canned/boiled fruit | (Type in here what kind of canned fruit or boiled fruit that you used.) |
| Cup | Condition of Gelatin After Refrigeration |
| 1 – Control | |
| 2 – Fresh fruit | |
| 3 – Canned fruit |
Evidence
Insert the picture you took of your cups after refrigeration. Make sure the picture includes a piece of paper with your name and UAG student number clearly legible.
Conclusions (Write in complete sentences.)
- Was your hypotheses correct? Explain.
- Which cup(s) did not gel? Explain why.
- Does the way that the fruit is prepared make a difference in the gelatin? Explain. Be thorough.
FAQs on Using Jell-o and Fruit to Demonstrate Enzymatic Activity
What is the Science Behind This Experiment?
Gelatin desserts are made from collagen, a protein found in animal tissues. Certain fruits, like pineapple, kiwi, and papaya, contain enzymes called proteases. These enzymes break down the bonds in proteins, like the collagen in Jell-o proteases in these fruits break down the collagen molecules into smaller pieces. This prevents the collagen from forming the cross-links necessary to create a gel, so your Jell-o stays liquid.
Which Fruits Work Best for This Experiment?
Pineapple, kiwi, and papaya are known for their high protease activity, making them ideal for this experiment. These fruits contain enzymes like bromelain (pineapple), actinidin (kiwi), and papain (papaya), which effectively break down collagen.
Can I Still Use These Fruits in Jell-o?
Yes! You can use these fruits in Jell-o if you heat-treat them first. Heating the fruit deactivates the enzymes, so they won’t break down the collagen. Canned pineapple, for example, has been heated during the canning process and won’t affect Jell-o’s gelling properties.
What are Some Other Variables I Can Test?
You can explore various factors that influence enzyme activity:
- Temperature: Compare the effects of fresh, frozen, and heated fruit on Jell-o.
- pH: Investigate how different pH levels (acidic, neutral, basic) affect enzyme activity.
- Enzyme Concentration: Test different concentrations of fruit juice to see how it impacts the breakdown of gelatin.
This experiment is a fun and engaging way to learn about enzymes, their specificity, and how environmental factors can influence their activity.
