Gelatin Salad
Submitter:
Tavis Sisson
Objective:
To investigate the effect of temperature on the action of an enzyme
Students are given a pre-lab that consist of leading questions designed to get the students to explore
concepts important to enzymatic reactions such as activation energy, anabolic/catabolic reactions,
endergonic/exergonic reactions, substrate, and active site.
** All gelatin and additives are cooled to room temperature before mixing.
The lab activity starts with the students making gelatin. The students are given commercial boxes of
gelatin and follow the instructions on the box to make the gelatin. One box provides enough gelatin for
two groups.
Each lab group prepares a sample of each additive. The additives are fresh pineapple chunks, canned
pineapple chunks, boiled pineapple chunks, McCormick’sTM meat tenderizer, and cooked McCormick’sTM
meat tenderizer. Equal amounts of gelatin are added to each of the additives, swirled, and stored in a
refrigerator overnight.
The normally thick texture of gelatin comes from the protein strands joining upon cooling. The students
observe changes to this texture based on the additive used in the sample. Bromelain is an enzyme found in
pineapple that catalyses protein. McCormick’sTM contains an enzyme called papain from papayas that has
similar enzymatic action. The students observe the consistency of the gelatin along with location of the
fruit in sample tube the following day.
From their observations in the lab students should deduce that high temperatures denature enzymes and
prevent their function. They are then asked to answer post lab questions such as:
Why do the instructions for meat tenderizer use tell you to put it on the meat prior to cooking?
What could be done when making fruit filled gelatin to keep the fruit suspended in the gelatin?