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Girl eating a strawberry.

The Power of Enzymes

About the Experiment

Enzymes are proteins that speed up specific chemical reactions in our bodies. They spur digestion, energy production, and cell function. Starch is a complex storage carbohydrate found in many foods (grains, potatoes, fruits) and is an integral part of our diet. Amylase is an enzyme that breaks down the starch into the simple sugar glucose.

Humans produce amylase in our saliva to jump start deconstruction of the starch molecules we eat, even before the food reaches our stomachs. In this experiment, we demonstrate the break down of starch to glucose using the amylase enzyme found in ginger root. This is a showcase for the power of enzymes.

Details

Ages: 5-15 | Time: 10 Minutes | Difficulty: Easy

 

What you Will Need

  • stamp set (less intricate designs work best, and
    use hard rubber stamps, not foam)

  • plain white printer copier paper

  • ginger root

  • knife and scissors

  • cutting board

  • iodine solution (10% Povidone-Iodine or Betadine)

  • spray bottle

  • safety glasses

  • paper towels

Let’s Do This!

  • Safety Note: Have an adult help with this experiment, including cutting ginger root and applying the iodine solution.

  • Make a 1% solution of iodine (dilute 10% over-the-counter solution 10x) by adding 1ml to 9ml of tap water in the spray bottle (any
    volume used is fine, just make a 1% solution that fits in the spray bottle).

  • Cut a standard 8.5x11” paper into quarters.

  • Select which stamps you want to use.

  • Ask an adult to cut slices of fresh ginger root. Rub the ginger juice on the stamp. This will be the invisible “ink”.

Bottle and paper.
Stamps - butterfly, flowers, and a heart.
Sliced ginger root and a stamp.

  • While still damp, stamp a design onto each paper quarter. Each stamp impression should have a fresh coat of the ginger juice “ink”.

  • Wait 10-15 seconds. Over a spot that can get messy have the adult “mist” the paper with the 1% iodine solution. Be sure not to spray too heavy a coating.

  • The stamp print will remain white (whitish) while the rest of the paper should develop a deep purple color, revealing the art created by the student.

Paper and spray bottle.
Flower stamp print lightest.
Flower stamp medium.
Flower stamp dark.
Man and child examining their science project.

Observations

  • The copier paper used for this experiment uses a starch coating to help the paper slip through the copier.

  • Ginger root is a good source of amylase and is relatively transparent, so it makes a good invisible ink.

  • Iodine (brown/yellow in solution) forms a complex with starch and turns purple. This has been a starch indicator dye for many years. Glucose does not complex with iodine, thus does not form a color.

  • The artwork formed is a negative print of the stamp and demonstrates that actions happening in our own bodies are sometimes invisible to the eye until we reveal them with scientific methods and measurement.

  • Where do you think enzymes are located in your body, besides your saliva?

  • How do enzymes affect your gut health (microbiome)?

  • Why is ginger root a good food substance for this experiment?

To learn more about ARS’s research on human health click here.

Download the printable "The Power of Enzymes" project PDF:
https://www.ars.usda.gov/ARSUserFiles/oc/AgLab/projects/PowerofEnzymes/The-Power-of-Enzymes.pdf 
 

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