Tastebud Testers

This topic submitted by Bair, Nauts, Obrecht, Smith & Wood ( WOODSJ1@miamioh.edu ) on 12/11/98 .


Lab Report
-The Taste Bud Testers-

I. Introduction:

The purpose of this project is to determine what types of water humans prefer and
if that preference is affected by food consumption. We plan to test four samples of water,
drinking fountain, sink, distilled, and bottled waters before and after eating. We believe
that bottled water will be the preferred water and that preference will not be affected by
food consumption. At the start of our experiment, we planned to test the water quality of
various sources of water to find out how their contents varied. We were hoping this data
would determine which type of water is best for drinking. After researching on this topic
we found that there was not much variation in what we wanted to test. We then decided
to change our focus more towards finding the qualities of drinking water and decided to
include a taste-test in our procedure. We then received feedback from our professor,
Scott Wankel, and his colleague, Hays Cummins, which led us to change our project once
again. We finally settled upon human preference for drinking water by doing taste tests.
Within our experiment we also decided to further extend our research and explore the
possibility of differences in preference based on gender. Although we had been told that
we probably wouldn't find a significant difference in the chemical makeup of the waters we
planned to test, we decided to do it anyways just to see what we would find. Our
experiment will prove whether or not bottled water is worth the price when compared to
tap water. Through research we will learn how the tongue senses taste and how taste is
affected by eating.

II. Relevance:

We have found many books containing helpful information on the subjects of both
drinking water quality and taste. We found the proper way to carry out a taste test. We
also learned that taste is affected by the temperature of water and contaminants in it. The
taste of bottled water can also be affected by it's plastic container. The government
regulates chemical and contaminant levels in drinking water. Water coming from a sink or
drinking fountain is affected by the types of pipes it comes through; PVC pipe is required
by the government in new homes. Mary Lyon Hall has metal water pipes. One of the
reasons we found our lab question interesting is because we tasted a significant difference
between the sink and drinking fountain water in Mary Lyon Hall, our dorm, and we
wanted to know the reason for this difference.
Experiments similar to our own have been done on a much larger scale by bottled
water companies. They have done chemical, contaminant, and other various tests on their
water. They also have performed taste tests involving two or more opposing bottled
water companies. From the research we have done, however, we have not found any
experiment already performed comparing the four types of water we plan on testing.
Since our exact experiment, to our knowledge, has never been done before, we hope our
results will shed some light on the question: Is bottled water worth the price?

Background Information:

*All information in this section is derived from our literary research. (See bibliography).

A) Water

To conduct experiments using drinking water it is important to know the different
components of the water that you are working with. We are using two samples of tap
water and two samples of bottled water for our experiment. There are several varieties of
bottled water but they can be simply classified as still or carbonated bottled water. We
will only be using still varieties of water for our experiment. Within types of bottled water
we will be using spring water and distilled water. Spring water is water that comes from a
source that flows naturally to the surface from an underground aquifer, or it may be
collected underground through a bore hole where a spring emerges. Spring water does
contain minerals in different variations according to brand or source. Distilled water is
water that has been treated by vaporizing, and then condensing the water to free it from
dissolved solids.

B) Human Taste

The human tongue is a complex sensory organ. The structure for taste on the
tongue is the taste bud. Taste buds are randomly arranged in clusters of cells contained in
goblet-shaped structures called papillae that are opened to the mouth cavity by small
pores. A single bud contains 50 to 75 taste receptor cells. The taste receptor cells are
long, slender cells which form and die within 7 to 10 days. Based on research there is not
a known difference between the male and female tongue. The tongue is supplied by two
nerves. The front two-thirds of the tongue is supplied by the lingual nerve and the back of
the tongue is supplied by the glossopharyngeal nerve. Both nerves also complete all
functions for touch, temperature, and pain sensitivity for the tongue. The signals are
transported to the anterior cerebral cortex where the different tastes are interpreted. The
tongue detects four different “tastes” and they are classified as sour, bitter, sweet, and
salty. Different areas of the tongue detect the different tastes. The taste of sour is
stimulated by the hydrogen ions of acids. The higher the concentration of hydrogen ions
the, greater the stimuli. The taste of salt is triggered by the molecules in most water-
soluble salts. Salts of lower molecular weight are predominately salty and those of high
molecular weight tend to be bitter. The bitter taste is caused by alkaloids and inorganic
salts that are high in molecular weight. Sweet is generally associated with the taste caused
by most organic compounds including alcohols, glycols, sugars, and sugar derivatives. It
is thought that the hydroxyl on organic compounds is the cause for the sweet taste but it
has not been proven.

(diagram)


C) Human Reaction to Water

Humans can detect the chemical differences in water by taste. Taste of water is at
its greatest intensity when at room temperature (22 degrees Celsius). Humans can taste a
difference in pH as well as the presence of chlorine, sulfide, magnesium, calcium, sodium,
potassium, iron, and zinc in water. Based on these relations between the human taste bud
and certain chemicals we can determine the scientific reasons for the difference in taste of
our water samples.

III. Material and Methods:

Materials:

-Distilled Water
-Naya Bottled Spring Water
-Drinking Fountain Water (Mary Lyon Hall)
-Sink Water (Mary Lyon Hall)
-Test Kits:
Iron
Magnesium
pH
Calcium
-Dixie Cups
-Survey Slips
-Pens
-Tables
-Survey Boxes

Methods:

We began by receiving permission to use Alexander Dining Hall as our testing site.
In order to obtain the materials we would need to do our experiment, we had to first go to
the Secretary and get a Limited Purchase Order. This purchase order would enable us to
go to the local Wal-Mart and purchase the water and the Dixie cups needed for our
experiment. We bought enough materials to test one hundred people, our Natural
Systems Section and even a few extras!
For our experiment, we will set up two tables in the Dining Hall; one for before
our participants eat, and the other for after their meal. On each table, we will set out a
sample of distilled water, bottled water, drinking fountain water, and sink water all at
room temperature. Each sample will be prepared in the same "Funky Fish" Dixie cup
design, as not to influence our participants with different designs. Each person will taste
the different types of water, which will be labeled a, b, c, and d, and from that, rate them
from the best tasting to the worst tasting and record it on the data sheet provided.

(data sheet)

After eating, our participants will go to the next table and repeat the procedure and record
their results on the provided sheet. This time we will mix up the order of the water
samples so they will not have any preconceived notions. We have planned to carry out
this experiment in a two hour dinner period. After the testing has been completed, we will
analyze our data and collaborate all of our results onto our data sheet.
We also plan to do four tests to find out what kinds of chemicals and sediments the
different types of water contain. The tests we plan to do are Iron, pH, Calcium, and
Magnesium. These test are being performed to give us a chemical science perspective to
go along with the biological perspective of the taste test to make this experiment
interdisciplinary. Our results will be recorded on our chemical data sheet.
When it is our turn to present our lab to the class we will conduct a two part
experiment. The first part will be to conduct the taste test in the same fashion we
performed in the cafeteria. Each student in the class will decide the type of water that they
prefer. We will group students with the same preference into groups. These groups will
then conduct the chemical tests for their preferred type of water. Hopefully the class can
then determine for themselves why the water they choose tastes best. We know that the
data collected by the class will be accurate because the results are based on personal
preference. The data from the chemical tests that they perform will be used for personal
reflection of the class. We will also use the class's data as a comparison device but not as
our actual data for the final lab results. We designed a special data sheet to be used by the
class to record and interpret their results. Then using Microsoft Excel we will create
graphs that display our results in a manner that is easy to understand.

(data sheet)

Our experiment will be unbiased for several reasons. The first reason is that our
participants have no immediate interest in our experiment, meaning that they would have
no reason to falsify their water ratings. Our participants come from diverse backgrounds
and are accustomed to drinking water from different sources which have varying quality
levels. We believe that this fact of diversity gives us random sampling along with the fact
that we do not choose who comes to dinner the evening we perform our test. Since we
are testing such a large number of people, this random sampling will assure statistically
sound data.

IV. Results:
To easily understand our results we decided to use pie and bar graphs (please see
graphs on the following page). The first two charts compare preferences before and after
eating. Both times tap water was preferred the most. Before eating, fountain came in
second with distilled being last. After eating, distilled came in second with fountain being
last. Spring came in third place both before and after eating. Our third chart compares
the results of the first two graphs side by side for easy understanding. The fourth chart
shows how many people changed their preference from what they preferred before eating
to what they preferred afterwards and who didn't change their preference. We found that
a majority of the people tested changed which water they preferred after eating. The
fourth and fifth charts show the preferences of females and males. Females preferred tap
water the most with spring, distilled, and fountain being equally liked. Males preferred tap
and distilled water equally with spring and fountain water both in second place being
equally preferred. The sixth chart compared the results of the fourth and fifth charts side
by side for easy understanding. The last chart showed the preference between the four
types of water combining the before and after preferences, and male and female
preferences.

(graphs)

V. Discussion:
We were surprised by many different aspects of our results. We predicted that
spring water would be the most preferred water by anyone, regardless of gender; however,
we were incorrect. Overall tap water was the most preferred water type for males and
females. Our dislike for the tap water in Mary Lyon Hall is what had initially inspired our
experiment and we are confused as to why it came out as the most preferred water type.
We have several ideas as to why the tap water sample ended up being everyone's favorite.
The numerous minerals and chemicals in the water may have been appealing to our test
subjects. Many of our test subjects were upper-classmen and have been living on this
campus for at least a year already. Due to this factor many people may be accustomed to
the taste of Oxford water.
During the testing process we ran out of the room temperature tap water sample.
To continue the test we had to use fresh samples. These samples were significantly colder
than the other samples and some of the test subjects commented on how the sample that
was colder was their favorite. We ran out of the samples late in our experiment so there
was not a significant number of results affected by this error. Even if we had eliminated
the statistics which involved the colder samples, tap water would still prevail as the most
favorite sample.
A small portion of the test subjects complained about the taste of the "Funky Fish"
Dixie Cups while sampling the water. This should not have affected our results because
all the samples were contained in identical "Funky Fish" Dixie Cups . Another interesting
and confusing result was related to the high number of males preferring distilled water
over the other samples. After extensive research we have concluded that there should be
no significant difference between taste preferences between males and females.
Now that we have reached the conclusion of our experiment, we realized some
things could have been done differently. There are two different views one can take for
making improvements in this experiment. If you were to scale down the experiment to
test less people it would be easier to set up a blind taste test. In this type of testing,
participants would sit down in a booth so as to be relaxed and not to be influenced by
other people. It would also be easier to control what the test subjects ate between testings
to ensure a controlled environment. On a larger scale, if the experiment had a larger
budget and more time, it would be possible to test many more people at different locations
and different times of day. The more data that was collected the larger the chance of us
finding data that would be a good representation of the population's preference. To make
our results more accurate we should have prepared an overabundance of water at room
temperature. As we stated in the above paragraph many of our test subjects complained
about the taste of the paper testing cups. Perhaps if we had used plastic cups they would
not have affected the taste of the water samples.
There are many factors that could have contributed to the results we received from
our taste test. Testing subjects could have eaten food before testing the "before eating"
sample of water. Subjects who hadn't eaten since the previous meal could be very hungry
and not consider the test samples as carefully as someone who was moderately hungry and
not rushing to get food. It is possible that some of our subjects were chewing gum before
or even during the sampling process which could have affected our results. Since we
couldn't control what types of food or how much people ate between testing, the after
eating results may have been affected. Everyone has preconceived notions as to what type
of water tastes good. If we could have had subjects define what type of area they grew up
in and where they currently lived, we could have looked at the results in groups of who
daily consumes city versus well and spring water. By doing this it is possible that we
could have found connections that would have given us more and data that could even
explain some of the results we currently have. An example of this could be that a majority
of the males we tested grew up in the same type of environment which could explain their
preference of distilled water. We noticed that males tended to come into Alexander
Dining Hall in large groups. Since they all try to test the water at once and all probably
just want to eat, we have reason to believe that they may have influenced each others'
decisions.

VI. Conclusion:

Our original hypothesis was proved wrong. The answer to our question,"Is spring
water worth its price?" was no. According to our results spring water is not worth buying
purely for taste. Many people buy spring water because they think it is purer than what
comes out of their tap. Typical spring water advertisements encourage a common
misconception that spring water is pure water. Even though spring water contains less
chemicals than tap water it is not necessarily the best water to consume. As our results
show, it is possible that certain chemicals enhance the taste of water. In the end there is
no one water that is chemically the best and whose taste is preferred for drinking.

Bibliography

American Association for the Advancement of Science. Biology of the Mouth. King
Printing Company, Maryland 1968.

Keough, Carol. Water Fit to Drink. Rhodale Press, Inc., Pennsylvania, 1980.

Millichap, J.G. Is Our Water Safe to Drink? PNB Publishers, Chicago, 1995.

"Sensory Reception." Encyclopedia Britannica. vol. 27, 1997 ed.

Sidel, Joel and Stone, Herbert. Sensory Evaluation Practices. Academic Press.
Redwood, CA, 1985.

Stewart, John C. Drinking Water Hazards; How to Know if There are Toxic Chemicals
in Your Water and What to Do if There Are. Envirographics. Hiram, OH, 1990.

Zoeteman, B.C.J. Sensory Assessment of Water Quality. Pregamon Press. Oxford, UK,
1980.

Zuane, John. Handbook of Drinking Water Quality. International Thompson Publishing
Company, U.S.A., 1997.


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