Effect of Carbonated Water's Color Perception of Its Taste
THE EXPERIMENTER

Researched by Cayley Rishor-Olney
2004-05



PURPOSE

The purpose of this experiment was to determine whether the color of carbonated water affected perception of its taste.

I became interested in this idea because I wanted to do something like a taste test. At first I was thinking about testing soft drinks.  Then I saw a project done by Krista Garcia in 2003 as a 7th grader. I knew it was exactly the kind of experiment I wanted to do. I decided to make some changes to her idea that might make it better.  My project is called “Drink color vs. Taste perception.”

The information gained from this experiment will be useful to caterers, cooks, or anyone who is involved in food or drink preparation.


HYPOTHESIS

My first hypothesis was that color would affect the perceived taste of the flavored water.

I based my first hypothesis on previous research done by Krista Garcia. She stated,”...the color of the flavored carbonated water affected the reported taste.” Her research can be found at http://www.selah.k12.wa.us/SOAR/SciProj2003/KristaG.html

My second hypothesis was that the red food coloring would be most effective in misleading the perceived taste.

My third hypothesis was that lemon-lime flavored water would be most unaffected by misleading colors.


Experimental Design

  • The constants in this study were:
  • The amount of carbonated water tasted (20ml)
  • Brand of flavored, sugar free carbonated water
  • Size, color, and type of tasting cup
  • Grade of subject
  • Temperature of carbonated water (7°C)
  • Location experiment took place
  • Experimenter interacting with subjects
  • Type and amount of food coloring 
  • Procedures used

The manipulated variable was the color of the carbonated water.

The responding variable was the percentage of times subjects accurately identified the taste. 

To measure the responding variable I will count the number of correct responses. 


 MATERIALS


QUANTITY
ITEM DESCRIPTION
1   
Box of gloves (latex free)
4 liters 
Unsweetened Carbonated Water, Lemon Lime flavored
4 liters 
Unsweetened Carbonated Water, Strawberry Flavored
4 liters 
Unsweetened Carbonated Water, Tangerine Flavored
500  
DIXIE cups 
1
Refrigerator that has a temperature of 7°C
1
Garbage can
30
 Response Sheets
1
Box of Pens or Pencils
1
Pack of food coloring (Green, Orange, & Red)
1
One Liter Liquid Measuring Cup (that can measure 20ml)



PROCEDURES

1. Collect permissions slips before experiment is conducted (subjects may not participate without the slips.)
2. Create response sheet for subjects to use during tastings.
3. Prepare carbonated water:
a. Buy 4 liters of each flavor of sugar-free carbonated water at the grocery store (strawberry, tangerine, & lemon-lime) also buy 500 small drinking cups to serve carbonated water and food coloring with the colors of green, red, and orange or yellow.
b. Select one flavor of water to color. Into a one-liter bottle of this flavor add five drops of red food coloring.
c. Shake bottle gently for 12 seconds to spread the color.
d. Refrigerate bottle at 7°C 
e. Repeat steps b-d with another bottle of this same flavor but add the next food color in this list (green, red, or orange.)
f. Repeat step e until all 3 bottles of this flavor are different colors.
g. Repeat steps b-f with three bottles of the next flavor.
h. Repeat step g with each of the last flavor.
4. Move 6 desks in testing classroom so that none of the subjects can communicate or see each other’s paper.
5. Wash desktops.
6. Bring a group of 6 students into testing room and seat them
7. Read subjects the instructions and answer any questions.  Tell them they may quit at any time.
8. Give each subject a response sheet and a pencil.
9. Pourer and server must wash hands before serving liquids or touching cups and put gloves on.
10. Conduct trial using the Sampling Order table.
a. The pourer, who is hidden from the subjects, puts 20 ml. of the correct color and flavor carbonated water for this trial into 6 of the small sample cups.
b. Server (only) gives subjects the carbonated water. 
c. Tell subjects to taste it then mark on the response sheet the flavor they think the water is.  Make sure the response is marked for this trial and color.
d. Repeat steps 10 a-d until all four colors of water have been tasted for this trial.
11. Conduct the remaining three trials repeating step 10.
12. Thank the subjects and send them back to class
13. Collect response sheets and discard used cups.
14. Wash desktops. Wash hands.
15. Repeat steps 6-14 for the rest of the groups that you test.
16. Tally correct responses using Sampling Order sheet as a guide.
17. Average scores


RESULTS

The original purpose of this experiment was to determine whether the color of carbonated water affected perception of its taste.

The results of the experiment were that strawberry flavored water was correctly identified most (2.0 of 3.0 possible), and lemon-lime was the least often identified (1.6 of 3.0 possible).  The waters colored red were identified correctly least often (1.7 of 3.0 possible) and orange colored water was identified correctly most (1.9 of 3.0).

See my data and graphs.

CONCLUSION

My first hypothesis was that color would affect the perceived taste of the flavored water.

The results indicate that my first hypothesis should be accepted, but the difference is extremely small. 

My second hypothesis was that the red food coloring would be most effective in misleading the perceived taste.

The results indicate that my second hypothesis should be accepted, because red colored water had the fewest correct taste identifications (so it was most misleading.)

My third hypothesis was that lemon-lime flavored water would be most unaffected by misleading colors.

The results indicate that my third hypothesis should be rejected because the strawberry flavor was identified correctly the most frequently.

Because of the results of this experiment I wonder how accurately people could identify the flavors with no coloring at all.  It is possible that these flavors are not easy to identify no matter what.  I am also interested in doing this test using adults compared to kindergarteners.  Really young kids might be more affected by the colors.

If I were to conduct this project again I would use all unsweetened carbonated water.  I would include many more subjects in my study.


RESEARCH REPORT

Introduction
It is likely that people learn and become familiar with specific combinations of colors and tastes.  The color/taste combinations become part of a person's memory, and people begin to expect certain colors to be associated with certain tastes.

Taste
Taste is an important sense by which human beings and animals detect many chemicals in the environment. In the body, specialized skin cells that detect tastes are grouped into clusters called taste buds. They are found primarily on the tongue, contained within small mounds called papillae. Taste buds also are present on the palate (back of the tongue on roof of the mouth) and other parts of the throat and mouth. The word taste refers to the quality of substance that is detected by taste buds. Taste is a component of flavor, smell, touch, and temperature sensation.


 There are five primary taste sensations: salty, sour, sweet, bitter, and umami. The taste of "salt" comes from sodium ions.  Sour taste is caused by acids.  Sweet taste (like from sucrose, or sugar,)is kind of the same as our odor receptor cells. Humans have at least 24 genes that "encode" bitter receptors. Umami receptors respond to the salts of glutamic acid like monosodium glutamate- a flavor enhancer used in many processed and especially Chinese foods.   It is associated with amino acids or the building blocks of protein.  Bacon hits our umami receptors because it is a rich source of amino acids.
 
A single taste bud contains 50-100 taste cells representing all five taste sensations. It used to be believed that there were separate taste areas on the tongue.  That has been proven to be untrue.

“Taste is important to our health for the following reasons.  Sweet foods are generally not poisonous, and provide needed calories. Sour fruits generally have needed vitamin C. We need a certain amount of sodium to remain healthy. “Umami is a signal for the presence of protein, which we need to survive. Finally poisonous substances, such as many alkaloids, are generally bitter” (D.R. Bauer et al, Cornell University).

 Taste is also influenced by smell. Holding your nose while eating something will probably make it difficult to identify the taste.


Color
 Many people don't realize how important color is to taste perception. Color affects our psychological impression of food. "If you don't believe it, try eating a familiar food in the dark."

 The colors used in foods and beverages came from both natural and synthetic sources. Think about orange juice and the natural color of the orange.  Think about yellow lemons.   People become familiar with specific combinations of colors and tastes.  People start to expect certain tastes to be associated with specific colors.

 Food and drink companies are very interested in whether color affects taste perceptions.   Companies work very hard to make their drinks the most desirable so they can sell more. If the company determines that changing the color of a drink can sell more product, you will probably see them change the color.

 In a study by DuBose et al., it was reported that subjects identified the correct flavor more often when the drink had the expected color.  For example, an orange-colored drink that was actually cherry flavored was often thought to taste like an orange drink; a green colored cherry drink was identified by many as lime.

 In another study by Oram, N., it was reported that younger subjects relied more on the color of the drink than adults did.  In other words, the younger subjects made more color-associated errors in identifying the correct flavor.

Flavor
Combining the sensations brought about by food or drink results in "flavor".  Smell, taste, feel in the mouth, and sight all impact the flavor of food and drink.  Chefs at fancy restaurants are aware of this, and try to create a "flavor", not only with the food and drink, but also with atmosphere.  This is all done to alter people's perceptions of their product.  An environment that is comfortable, has attractive smells; and a product that is presented in a beautiful "package" is probably going to be more desirable.


Tongue
Tongue is the chief organ of taste. It also helps in chewing and swallowing, and helps to make words come out of your mouth right. The tongue is a muscle in the mouth.


Taste Buds
The average human has about 10,000 taste buds; however, they're not all on the tongue. Some are under the tongue; some are on the inside of the cheeks; some are on the roof of the mouth. Some can even be found on the lips; these are especially sensitive to salt.  Skin on top surface contains 10,000 tiny chemical sensing bodies called taste buds. The tongues spongy looking surface accur in four shapes: filiform (pointed), foliate (leaf shaped), fungiform (mushroom shaped), and circumvalete (ring shaped). Each poliate, fungiform, and circumvalete papilla holds 1-200 taste buds. Filiform papillae are the most numerous type. They contain no taste buds. Inside of a taste bud are a dozen taste cells, and there can be up to 10,000 taste cells on a tongue.
 
BIBLIOGRAPHY


Burich, Raymond L. “Tongue” World Book Online Reference Center. 2004. World Book, Inc. 17 Nov.2004 http://www.woldbookonline.com/wb/Article?id=ar561000&st=tongue

D.R. Bauer, et al, Cornell manipulating flavor perception in functional products
http://www.naturalproductsinsider.com/articles/241fbff1.html

Garcia, Krista. “Drink Color Vs. Taste Perception” Selah Home Page Nov.17.2004.
http://www.selah.k12.wa.us/SOAR/SciProj2003/KristaG.htlm

Halpern, P. Bruce. “Smell” World Book Online Reference Center. 2004. World Book Inc. 17 Nov. http://www.worldbookonline.com/wb/Article?id=ar515080&st=Smell

Johnson, Alan Kim “Senses” World Book Online Reference Center. 2004. World Book, Inc. 17 Nov. 2004  http://www.worldbookonline.com/wb/Article?id=ar501400&st=Senses

“Smell” Microsoft Encarta Reference library 2005 November 10, 2004

Smith, David V. “Taste” World Book Online Reference Center.2004.World Book, Inc. 17 Nov. 2004. http://www.worldbookonline.com/wb/Article?id=ar548120&st=Taste

“The Taste Process.” Allayurveda.com. January 5, 2005    http://www.allayurveda.com/dietp_tprocess.htm
 


ACKNOWLEDGEMENTS

I would like to thank the following people for helping make my project possible:
  •  My mom for helping me get my research report done and for pushing me to do my science project perfectly as possibly.
  •  Mr. Newkirk for helping me with my science project.
  • Mrs. Helms for printing out sub titles for my board.
  • Sierra for helping me with my project when I did my experimenting.
  • Natalie for helping me when I was stuck.
  •  Mr.Ollivier for helping me pick a science project, for letting me take his students for my testing as my subjects, and for taking us to the computer lab to work on our projects.
  • Mrs.Snodgrass for letting me use 2 classes of her students as my subjects.

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