School Improvement in Maryland


ENGAGEMENT (1.b)
“Pineapple/Jell-O™ Lab”
 

Rationale:

  • To show that food items contain enzymes.
     

Time:

  • Approximately 30 minutes
     

Objectives:

  • To introduce students to the concept of enzyme and substrate reactions
     

Materials: (for class of 30)

  • Prepared 2-3 cm Jell-O™ Brand gelatin cubes (4-5 cubes per group)
  • Shallow dish or pan
  • Fresh and canned pineapple juice
  • Blender
  • Cheesecloth
     

Overview: (for class of 30)

  • Students will use pineapple juice as an enzyme and Jell-O™ as a substrate to illustrate an enzyme/substrate complex.
  • Students will discover that the processing of food will denature enzymes.
     

Procedure:

  1. Teacher or students prepare Jell-O™ the day before this activity.
  2. Teacher or students prepare fresh pineapple juice by pureeing fresh pineapple in a blender. The puree should be strained through cheesecloth to separate the pulp from the juice. Repeat this procedure for the canned pineapple.
  3. Student groups receive a sample of either fresh or canned pineapple juice and cubes of Jell-O™.
  4. Place Jell-O™ cubes in a shallow dish or pan.
  5. Pour juice sample over the Jell-O™ cubes until the bottom of the dish or pan is covered.
  6. Students should observe the experimental set-up for 30 minutes and record observations at 5 minute intervals.

Background information:

  1. Gelatin is made from a protein called collagen which comes from the joints of animals. Gelatin may be dissolved in hot water. 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 semi-solid mass that is so recognizable as Jell-O™.
     
  2. Pineapple belongs to a group of plants called Bromeliads. Kiwi, papaya, and figs are other types of Bromeliads. The enzyme in pineapple juice that is responsible for the breakdown of collagen is bromelin. The process of canning pineapple denatures the bromelin, rendering it incapable of catalyzing the break down of gelatin.

For additional information and optional activities see the following resources: