
Fresh Pineapple and Jello: Bromelain at Work
Easy
Why does Jello refuse to set when you add fresh pineapple? Fresh pineapple contains an enzyme called bromelain (a protein-breaking chemical). Bromelain breaks apart the gelatin protein that gives Jello its firm texture.
You make two batches of Jello. One batch gets pieces of fresh pineapple. The other gets canned pineapple. After refrigerating both batches you check which one sets into a solid gel.
The canned pineapple batch sets normally. The fresh pineapple batch stays liquid because bromelain digests the gelatin. Canning heats the pineapple enough to destroy the enzyme.
Hypothesis
The hypothesis is that the bromelain enzyme in fresh pineapple will degrade the gelatin protein in Jello, making it impossible to gel.
Method & Materials
You will make two batches of Jello, one with canned pineapple and one with fresh pineapple, and observe the results.
You will need fresh pineapple, canned pineapple, Jello, a bowl, boiling and cold water, a spoon, paper cups, and a knife.
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See what’s includedResults
The results of this experiment showed that the Jello made with canned pineapple gelled, while the Jello made with fresh pineapple did not. This is because the bromelain enzyme in the fresh pineapple degraded the gelatin protein, digesting it into a bowl of amino acids.
Why do this project?
This science project is interesting and unique because it shows how the enzyme bromelain can have a dramatic effect on the properties of Jello.
Also Consider
Experiment variations to consider include testing other fruits that contain protein-degrading enzymes, and determining the temperature at which the enzyme denatures.
Full project details
Additional information and source material for this project are available below.Related video
These videos explain the science behind this project and demonstrate key concepts used in the experiment.
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