Project perception of taste.

Are there vegetables that you have never liked to eat just because they don’t look good at dinner time? Have you ever wondered what the flavor of a piece of candy is based on its color? Do you ove the smell of your favorite meal? The ways we experience taste are why you answered these questions the way you did. In the following experiments we are going to make good food look eally bad (really, really yucky). We will see how we perceive the color of a food and how we expect it to taste. And finally we will find out how much we actually taste and how much of it is smell!

Like in all experiments let’s start by gathering all of our equipment and ingredients first. That way we won’t be searching for, or running out of anything.

Ingredients:

Carrots roughly chopped 1 cup
Fresh Spinach or other greens 1 cup
Fresh Strawberries sliced 1 cup
Your favorite apple chopped 1 cup
Assorted flavored candies 1 cup
(Jelly beans or spice drops work great)
Baking soda 4 Tbsp
Vinegar or Lemon Juice 4 Tbsp


Materials:

2 Stainless Steel pots with tight fitting lids
(other non-reactive pots well too, just not aluminum or copper)
Small bowls or dishes
Measuring spoons
Blindfold
Nose clip (or just your fingers)
Paper to record findings

Now we want to cook our fruits and vegetables. This will require the stove so ask an adult for help. Divide your chopped carrots between the two pans, add some water to barely cover them.

To one pot add 1 Tbsp of vinegar or lemon juice. To the other pot add 1 Tbsp of baking soda (you may want to label your pots so you know which is which). Cover and cook over medium low heat until the carrots are softened, about 10 minutes. Drain and place each in a separate dish. Now we are going to repeat this with the spinach, apples and strawberries one at a time. Rinse the pots in between each vegetable, and don’t mix up which fruit or veggie is cooked with the baking soda and which is cooked with an acid. It might help to write acid and base on separate pieces of paper and put the corresponding dishes on each until you are done cooking the other fruits and veggies!

What happened to my yummy food?!

As you can see some of your samples turned nasty colors, while others did not change or were actually brighter, depending on what you cooked them with, baking soda or vinegar/lemon juice. Which ones look bad, which ones look good? The chemicals in plants that give them color are called pigments. Most pigments are anti-oxidants. Anti-oxidants are really good for our bodies, but our fruits and veggies can loose their good pigments depending on how they are cooked and what they are cooked with. All plants carry a mix of pigments to achieve their color and efficiently conduct photosynthesis. It is the primary pigment in each plant that gives them their dominant color. Green plants are primarily colored by chlorophyll, orange plants and some yellow plants like rutabagas contain carotene. Red and white plants contain flavonoids. The chlorophyll in spinach reacted with the acid and was leached into the water, leaving drab green and brown spinach. The carrots at first looked about the same, but as time passed the carrots cooked with baking soda turned green, revealing the chlorophyll also in the root. The strawberries and apples both turned brownish green in an alkaline cooking solution also. You might have noticed that they and the apples bubbled a whole lot too, that was the acid in the fruit reacting with the baking soda! Which of each sample would you rather eat? The ones that changed to funny colors, or the ones that did not?

Hey, Where’d the taste go?

This next experiment you get to try different flavors of candy. Jelly beans and spice drops work

best because we have an idea of what their flavor should be by the way they are colored. You might want a glass of water to help get the taste of the each candy out before going on to the next. You need to find 2 of each color of candy, at least 5 different colors are perfect. Tie a blindfold over your eyes, no cheating it’s more fun if you’re surprised. With the first candy pinch your nose before you bite in. Hold your nose while you chew. What do you taste? Now before you swallow let go of your nose, what do you taste now? Record your results for each color before proceeding to the next. After you have tried each color once with the blind fold on and your nose pinched, go ahead and try each color another time, this time you can see and smell it. Based on your observations guess which colors tastes like which flavors, record your results. Do they taste the same now that you can see them? Did you guess correctly what each color would taste like?
Here’s why:
Taste only comes in five flavors, salty, sour, sweet, bitter and savory (umami). Most of what we actually taste is odorous, or we can smell it. Our taste buds are in our mouths, but our olfactory glands (smelling glands) are in our nose. Air containing odors is carried from our mouths into our noses. If we plug our nose we can’t smell, all we can taste is the sweetness from the candy and perhaps some bitterness or sourness depending on the candy flavor. When you unplugged your nose there was the flavor that had gone missing. There are many different flavors that the candy can be colored with, but only a few different colors can be used to represent different tastes. For instance raspberry, watermelon, strawberry and cherry are all red. Limes and sour apples are green. Sometimes we might associate one color with one flavor but are surprised by what they actually taste like; especially when we confuse ourselves by only tasting something and then smelling it without our eyes to see what it might be. You might have thought you were tasting lime or raspberry and found out it was sour apple or cherry.

Come by next month so we can explore proteins. Proteins are very complex molecule found in all life. With some easy experiments we will show some of their functions and what we can do with them in the kitchen.