Gelatin is a popular dessert.
Enzymes are biological assistants, also known as catalysts. Gelatin is a processed protein found in humans and many animals. Several enzymes break down this protein. This protein is called collagen and is found in many foods, such as textured candy, marshmallows and some cream cheeses. At room temperature, gelatin protein is in the form of a triple helix. Learn about gelatin by conducting different science projects about enzymes at home or in the classroom with adult supervision.
Prepare gelatin
Prepare a fruit gelatin dessert according to package directions.
When the powder gelatin dissolves in boiling water, the protein structure changes. The water breaks helical bonds, so the polypeptide chains detach. Once cold water is added to the solution and it chills for a few hours, the polypeptide chains reform imperfectly into a tight helix structure. Water is trapped inside the chains' pockets and gaps. This is why the dessert jiggles and is so much fun to eat.
Enzymes in Fruit Juices
Gather fresh fruit juices, such as pineapple, papaya, kiwi and apple juices. Label bowls with the names of each juice and one "water." Dissolve gelatin in boiling water and divide mixture among the small bowls. Add a small amount of cold water and juice to the designated bowl. Stir each bowl well with clean utensils and chill overnight.
Observe the bowls that congeal. Some juices, including pineapple, papaya and kiwi, contain an enzyme that digests protein, so they do not congeal.
Temperature and Juice Enzymes
Temperature can destroy the enzyme in pineapple juice that breaks down protein. Label two small bowls "heated juice" and "fresh juice." Heat some pineapple juice in a pot over medium-high heat for five minutes. Remove from heat and cool in refrigerator until cold. Chill the fresh juice in a separate container. Dissolve gelatin in boiling water and divide equally into the two bowls. Add the juices to the designated bowls. Stir well with clean utensils and chill overnight.
Observe the bowl that congeals and the one that doesn't. By heating the pineapple juice, it's protein-digesting enzyme is destroyed, allowing the gelatin desert to congeal.
Salt and Gelatin
Salt changes the freezing point of water. See how salt changes the rate that gelatin congeals. Label three bowls "no salt", "1 tablespoon" and "3 tablespoons." Dissolve gelatin in boiling water and divide into the three bowls. Add 1 tbsp. and 3 tbsp. of salt to the designated bowls. Add cold water to each bowl and chill. Observe the state of the three bowls every four hours for 16 hours. Salt slows the rate that gelatin congeals.
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