FOOD EXPERIMENT: RED CABBAGE RIDDLE
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The following experiment is designed to supplement activities in already
existing food and nutrition projects. First read the section "Caution-Be
Science Wise" and then help 4-H members work through the experiment.
CAUTION - BE SCIENCE WISE!
Before you begin any science experiment, you should always follow these basic
rules:
1. Be sure to read ALL directions before starting the experiments.
2. In many experiments, a "control" is used. The control is the standard
against which you compare the experimental food.
3. When doing the experiments, keep everything the same as the control except
for the one thing the directions say to change. Use the same size pans,
the same type of bowls and the same mixing speeds. Be sure that just ONE
thing changes each time.
4. Be sure to label each food when conducting these experiments. Use a piece
of masking tape, a marking pencil, a crayon or anything that will help you
remember which food is which. In some experiments, you'll have no trouble
telling the foods apart. In others, the foods may look the same.
5. The experimental food is not meant to be perfect. Since you are purposely
doing something wrong, you can't expect it to be perfect! So it's all
right when something turns out "bad." That's what is SUPPOSED to happen.
6. Not all experiments in food science yield products that can be eaten.
NEVER SAMPLE PRODUCTS IN AN EXPERIMENT UNLESS YOUR LEADER SAYS THEY ARE
SAFE TO EAT.
7. Records are an important part of any scientific project. You should write
down what happens in each experiment. Experiments may not turn out exactly
the same every time. Recording your results will help you and others who
may try to repeat your experiment.
THE RED CABBAGE RIDDLE
INTRODUCTION
Anthocyanins (red) and anthoxanthins (white) are two color pigments found in
vegetables. When a base is added to these pgiments, the anthocyanin turns
blue and the anthoxanthin turns yellow.
Red cabbage is a food that contains both of these pigments. If you add baking
soda (a base) to a red cabbage, you may be in for a surprise. Give it a try!
INGREDIENTS
Outer 3 leaves of red cabbage
1 tablespoon baking soda
Water
EQUIPMENT
Saucepan
Sharp knife
Cutting board
Measuring spoons
Wooden spoon for stirring
PROCEDURE
1. Shred the cabbage with the knife. Put the shredded cabbage into the
saucepan and add just enough water to barely cover the cabbage.
2. Add the baking soda. Stir.
3. Bring the water to a boil. Lower the heat to medium and cook for about 5
minutes, stirring occasionally.
4. Observe any color changes and fill in the blanks below:
* What color did the water turn? __________________________________________
* What color did the red cabbage turn?_____________________________________
5. See if you can answer this question based on what you observed:
* Why do you think the cabbage changed color?
EXPLANATION
Red cabbage contains anthocyanins (red) and anthoxanthins (white). When a
base such as baking soda is added to red cabbage, the anthocyanin pigment will
turn bluer and the anthoxanthin pigment will turn yellow. Since blue and
yellow combine to make green, the red cabbage turns green.
SOURCE: Food Mysteries, Michigan State University
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Updated 8/15/05