Name: ______Date: ______Hour: ____

PINEAPPLE FLAVORED JELL-O?

Background:

Gelatin is obtained from selected pieces of calf and cattle skins, demineralized cattle bones (ossein), and porkskin. Contrary to popular belief, hoofs, 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 porkskin; 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 jiggling, wriggling pseudo-solid that we all know and love as Jell-O™.

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

Objective:As a result of these lab exercises, you will be able to…

Investigate enzyme activity.

Materials:Sample cups (2 per group)

Jell-O™ liquid (sugar free jello)

Fresh pineapple (1 piece per group)

Canned pineapple (1 piece per group)

Procedure:

Day 1:

  1. Fill two sample cups ½ to ¾ full with hot Jell-O™ liquid (obtain from teacher).
  2. Put a piece of fresh pineapple in one cup and a piece of canned pineapple in the other cup.
  3. Label each container with the group name, hour, and either “fresh” or “canned.”
  4. Draw a picture of your two sample cups in the section below (#1 below).

Day 2:

  1. Observe the sample cups containing the canned pineapple and fresh pineapple.
  2. Draw a picture of the two sample cups in the section below (#9 below).

Observations/Data/Follow-Up Questions:

  1. Day 1: Draw a picture of each of the sample cups. Be sure to indicate which drawing shows the canned sample and which shows the fresh sample of pineapple.

Follow-Up Reading:

The pineapple belongs to a group of plants called Bromeliads. Kiwi, papaya, and figs are other types of Bromeliads. The enzyme in fresh pineapple that is responsible for the breakdown of collagen is bromelin. The process of canning pineapple denatures the bromelin in such a way that it can no longer catalyze the breakdown of gelatin.

  1. What macromolecule is present in Jell-O™?
  1. In terms of an enzymatic reaction, what is collagen?
  1. In terms of an enzymatic reaction, what is bromelin?
  1. Draw a picture of the reaction that is taking place. Be sure to include and label the five standard components: enzyme, substrate, reactants, enzyme-substrate complex, and products.
  1. Why do you need to add canned pineapple or why does fresh or frozen pineapple need to be cooked before adding to Jell-O™?
  1. Fresh pineapple is used as a meat tenderizer. Why is this? Explain.
  1. Day 2: Draw a picture of each of the sample cups and describe the results. Be sure to indicate which drawing shows the canned sample and which shows the fresh sample of pineapple.

Knife

Pineapple

Canned Pineapple

Dixie Cups