Title: Solidification of Jello
Aim: To investigate how heating affects the enzyme bromelain in pineapple and its influence on the
solidification of jello.
Problem Statement: When pineapple is added to jello, it sometimes prevents solidification. The
objective is to determine whether heating pineapple, using the same fruit source, impacts jello’s ability
to solidify.
Hypothesis: Heating pineapple deactivates the enzyme bromelain, which otherwise breaks down gelatin
proteins and prevents jello from solidifying. Therefore, jello with heat-treated pineapple will solidify,
while jello with untreated pineapple will not.
Apparatus and Materials:
2 sets of clear glass bowls or containers
Measuring cups
Stirring spoon
Refrigerator
Thermometer
Timer or clock
Stove or microwave for heating
Reagents:
1 box of powdered gelatin
Fresh pineapple (pre-cut or whole)
Water (for dissolving gelatin)
Sugar (optional, depending on recipe)
Method:
1. Prepare two sets of jello mixtures using the same batch of fresh pineapple:
Set 1 (Untreated Pineapple Jello):
1-Cut pineapple into small pieces.
2-Heat water to the required temperature for dissolving gelatin.
3-Mix gelatin powder into the hot water and stir until fully dissolved.
4-Add the raw, untreated pineapple pieces to the gelatin mixture and stir.
Set 2 (Heat-Treated Pineapple Jello):
1-Cut an equal portion of pineapple into small pieces.
2-Heat these pieces by boiling them in water for 5–10 minutes to denature the bromelain enzyme.
3-Drain and cool the pineapple.
4-Prepare gelatin as before by dissolving in hot water.
5-Add the heat-treated pineapple pieces to the gelatin mixture and stir..
6- Pour both mixtures into separate containers.
7- Let the mixtures cool for 10 minutes at room temperature.
8-Transfer the containers to the refrigerator and allow them to set for at least 4–6 hours or overnight.
9-After refrigeration, observe and record the state of each jello sample.
Variables:
Manipulated - Treatment of pineapple (heat-treated vs. untreated)
Responding -Degree of jello solidification
Control-Type and amount of pineapple, volume of gelatin, water temperature, refrigeration time and
temperature, and container type
Treatment of Results:
Observe and document whether each jello sample has set.
Compare texture, consistency, and firmness.
Record whether the jello is liquid, partially set, or fully solid.
Observations: TABLE SHOWING THE OBSERVATIONS FOR EACH TREATMENT FOR EACH TEST:
Treatment of Pineapple Observations
Heated
Untreated
Expected Results:
The jello with untreated pineapple will remain liquid or only partially set due to active
bromelain.
The jello with heat-treated pineapple will solidify completely, as heat will denature the
bromelain enzyme, allowing gelatin proteins to form a gel.
Precautions:
1-Ensure the gelatin is completely dissolved in water at the correct temperature (around 50–60°C).
2-Properly heat the pineapple to denature bromelain without burning it.
3-Avoid cross-contamination between the treated and untreated pineapple.
4-Ensure equal amounts of pineapple are used in both sets.
Assumptions:
1-It is assumed that the pineapple used contains active bromelain before heating.
2-It is assumed that the heating process is sufficient to deactivate the enzyme.
Limitations:
1-The bromelain concentration may vary naturally in different parts of the pineapple.
2-The experiment uses only one heat treatment method and one gelatin recipe.
3-It does not account for external factors like humidity or minor temperature differences in the
refrigerator.
Reflection: This experiment reinforces how enzyme activity can influence physical properties in food
science. Bromelain, found in fresh pineapple, breaks down gelatin's protein strands and prevents gel
formation. By applying heat, we are able to deactivate the enzyme, showing a clear difference in
outcome using the same fruit. This knowledge has broader applications in culinary arts and
biochemistry, especially in understanding enzyme denaturation and food preparation processes.
