Pineapple and Jell-O; Good luck with that!

Background:

Gelatin is obtained from selected pieces of calf and cattle skins, demineralized cattle bones (ossein), and pork skin. Contrary to popular belief, hoof, horns, hair, feathers, or any keratin material is not a source of gelatin. There are two forms of gelatin: Type A, derived from acid processed materials, primarily pork skin; and Type B, derived from alkaline or lime processed materials, primarily cattle or calf hides and ossein.

Gelatin is made from a protein called collagen, which comes from the joints of animals. Gelatin dissolves in hot water and congeals (jells) at cooler temperatures. As the dissolved gelatin mixture cools, the collagen forms into a matrix that traps the water. As a result, the mixture turns into the jigging, wiggling, pseudo-solid that we all know and love (yeah right) as Jell-O.

The pineapple belongs to a group of plants called Bromeliads, kiwi, papaya, and figs are other types of Bromeliads, There is an enzyme in fresh pineapple that is responsible for the breakdown of collagen. It is called bromelin.

Note: When making Jell-O, the directions read: “Fresh or frozen pineapple must be cooked before adding.”

Procedure:

  1. Fill the two sample cups ½ to ¾ full with freshly made Jell-O.
  2. Put approximately 6 pieces of fresh pineapple in 1 cup.
  3. Put approximately 6 pieces of canned pineapple in the other cup.
  4. Label cups accordingly.
  5. Put both cups in the refrigerator for approximately 4 hours.
  6. Observe and note differences.

Pre-lab questions:

  1. Define enzyme:
  1. What enzyme is found in pineapple?
  1. The substrate that this enzyme acts upon can be found in Jell-O. What is it?
  1. Where is the substrate found?
  1. What kind of macromolecule is the substrate? hint: Your book, section 2.4, gives you a list of the 4 macromolecules and the paragraphs above are very helpful!
  1. What is the monomer of this macromolecule (use your book, 2.4)?
  1. What do you think will happen with the Jell-O and the canned pineapple? How about the fresh pineapple?

Post-lab questions:

1. Describe each cup:

  1. Canned pineapple
  1. Fresh pineapple
  1. Why are they different? Explain your answer using enzymes and denature.
  1. Draw a picture of the reaction taking place. Be sure to indicate and label the five standard components: enzyme, substrate, reactants, enzyme-substrate complex, and products. *This can be a diagram. You do not have to draw the actual molecules.

4. Why do the instructions on the Jell-O box include: “Fresh or frozen pineapple must be cooked before adding.”?

  1. Fresh pineapple can be used as a meat tenderizer (people like to put it on ham). Why is this? Explain.