Pineapple Lab
The Effect of Pineapple Juice on the Gelling Time of Gelatin
Abstract:
Fresh pineapple is known for not being able to gel and this experiment is aimed to figure out why. Bromelain is an enzyme the breaks the chains in proteins making them inactive and pineapple are known for having it. In this experiment we tested other factors that pineapple contain to pin point what the culprit was. It was discovered the Bromelain was actually the reason that fresh pineapple won’t gel but if you boil the pineapple or pasteurize it, it denatures the enzyme, allowing it to gel.
Introduction:
Why does canned pineapple make excellent jell-o but fresh pineapple falls short? A few hypotheses are that the fresh pineapple is too acidic, that Bromelain, an enzyme found in pineapple might break down the protein bonds of collagen, or there is a high concentration of fructose in the fresh pineapple. Our prediction was that if any one of these three were correct then the fresh pineapple would not gel. Below is an experiment that we did with fresh pineapple juice and canned pineapple juice; we tested each of them to see which gelled first. We then tested each of our hypotheses above to see which property had a negative reaction to collagen.
Method:
To test our hypothesis first we crushed fresh pineapple using a mortar with a pestle until we had about five ml of juice. We used the pipette to transfer the five ml of pineapple juice into a test tube. After thoroughly cleaning the mortar, we then crushed canned pineapple in the mortar until we had five ml of pineapple juice. We transferred the five ml canned pineapple with a pipette into a second test tube.
After labeling the test tubes canned and fresh we transferred ten ml of liquid gelatin with a pipette into each of the test tubes. We quickly covered the test tubes, mixed the compounds and placed them in an ice bath at approximately 2.42.
To test which factor (Bromelain, Ascorbic Acid, or Fructose) was the
Abstract:
Fresh pineapple is known for not being able to gel and this experiment is aimed to figure out why. Bromelain is an enzyme the breaks the chains in proteins making them inactive and pineapple are known for having it. In this experiment we tested other factors that pineapple contain to pin point what the culprit was. It was discovered the Bromelain was actually the reason that fresh pineapple won’t gel but if you boil the pineapple or pasteurize it, it denatures the enzyme, allowing it to gel.
Introduction:
Why does canned pineapple make excellent jell-o but fresh pineapple falls short? A few hypotheses are that the fresh pineapple is too acidic, that Bromelain, an enzyme found in pineapple might break down the protein bonds of collagen, or there is a high concentration of fructose in the fresh pineapple. Our prediction was that if any one of these three were correct then the fresh pineapple would not gel. Below is an experiment that we did with fresh pineapple juice and canned pineapple juice; we tested each of them to see which gelled first. We then tested each of our hypotheses above to see which property had a negative reaction to collagen.
Method:
To test our hypothesis first we crushed fresh pineapple using a mortar with a pestle until we had about five ml of juice. We used the pipette to transfer the five ml of pineapple juice into a test tube. After thoroughly cleaning the mortar, we then crushed canned pineapple in the mortar until we had five ml of pineapple juice. We transferred the five ml canned pineapple with a pipette into a second test tube.
After labeling the test tubes canned and fresh we transferred ten ml of liquid gelatin with a pipette into each of the test tubes. We quickly covered the test tubes, mixed the compounds and placed them in an ice bath at approximately 2.42.
To test which factor (Bromelain, Ascorbic Acid, or Fructose) was the
Cited: Biology 150, Biological Principles Laboratory Manual, Spring 2012