The 1st purpose of this experiment was to determine which fruit had
a greater rate of dehydration.
The 2nd purpose of this experiment was to determine the percentage of
weight loss for each fruit.
I became interested in this idea when my mother had sliced a variety
of fruits and left them on the counter. The next day I went to eat them
and they were dried entirely.
The information gained from this experiment would benefit fruit producers
and fruit growers because they would know which fruits dehydrate the fastest
and they might be able to prevent it.
My 1st hypothesis was that the apple would have the greatest rate of
My 2nd hypothesis was that the apple would have the greatest percentage
of weight loss.
I base my 1st and 2nd hypothesis on Fredrick J. Francis, a food industry
scientist, who stated, "The apple has a rather large amount of moisture."
Therefore, I think that the apple will dehydrate the fastest along with
losing the most weight due to having a large amount of moisture.
The constants in this study were:
The manipulated variable was the kind of fruit that was being dehydrated.
Air temperature in testing environment
Approximate mass of the fruit in test tray
Thickness of the slices
Amount of heat
Amount of light
Heat level in dehydrator
Fan speed in dehydrator
The 1st responding variable was the rate of dehydration and the 2nd
responding variable was the percentage of weight loss.
To measure the 1st responding variable I determined the amount of time
each tray of fruit took until the mass no longer decreased.
To measure the 2nd responding variable I subtracted the original mass
of the fruit from the ending mass of the fruit, and then I would divide
the difference by the original beginning mass of each fruit.
||Clean dehydration trayís
||Fresh flavored fruits
||Clipboard with paper
1. Label 2 test trayís A and B
2. Measure the mass of both trayís A and B
3. Slice each fruit (0.5 millimeters thick)
4. Arrange on each fruit tray a single layer of fruit
5. Record initial mass of each tray of fruit, (including tray)
a. Set temperature
b. Start timer
c. Check every 60 minutes and record mass
d. Rotate the fruit tray in a clockwise manner, each 60 minutes
e. Repeat step C until mass no longer decreases more than 1.0% of the
original fruit mass
f. Record time
7. (Optional) Repeat steps 2-5 with same fruit for following trials
8. Repeat 2-6 for next type of fruit
The 1st original purpose of this experiment was to determine which fruit
had a greatest rate of dehydration.
The 2nd original purpose of this experiment was to determine the percentage
of weight loss for each fruit.
The results of the experiment indicated that the banana had the fastest
dehydration rate of the tested fruits. The fruit with the slowest dehydration
rate was the grapefruit. The banana took 6 hours, followed by the apple
at 7 hours, orange at 10.6 hours and the grapefruit at 11.3 hours.
However, the apple had the greatest percentage of weight loss, and the
banana had the lowest. The apple had 88% of its mass evaporated, the orange
had 86%, grapefruit with 85%, and the banana at 69% of its moisture evaporated.
View my table and graph.
My 1st original hypothesis was that the apple, due to lots of moisture,
would dehydrate fastest.
The results indicate that the 1st hypothesis should be rejected because
the banana dehydrated faster than any other fruit.
My 2nd original hypothesis was that the apple would have the greatest
The results indicate that the 2nd hypothesis should be accepted because
the apple did lose a large percentage of weight.
Because of the results of this experiment, I wonder if I dehydrated
more fruits would the banana still perform as it did and if I had used
the a different method of dehydrating would the outcome change.
If I were to conduct this project again I would dehydrate more types
of fruit, and I would also conduct more trials for each type of fruit.
Dehydration is an important method of preserving food. Dehydrated fruit
will store for long periods of time, where as fresh fruits will eventually
spoil within 1 to 2 weeks. It provides fresh tastes after being stored
for weeks and also gives a good source of vitamins, proteins, and other
Dehydration is when there in too much water and salt loss. When the water
level falls below a certain area the salts will increase and will continue
to do so until the water level reaches or surpasses its original level.
When this happens it stimulates the drinking molecules and causes the need
for water, known as thirst. When thirst happens it usually is treated with
many different beverages rather than water, but however a portion is obtained
by the foods and water from the body cells. Thirst is controlled by hypothalamus,
part of the brain.
Dehydration occurs to many mammals as well as food products. In mammals
dehydration causes dryness of throat, mouth, nose, and many mucous membranes.
These drynessís usually occur in dry climates or during winter heating
season. Dehydration most likely will occur in both men and women because
there is no measurable difference between genders. Mammals lose water daily
through urine, sweat, tears, and saliva. When we lose sweat it reduces
the volume of blood, which will eventually increase the sodium level. Sweat
also contains minerals such as sodium, potassium, and chloride. When these
minerals mix they will decrease your overall blood volume. This also makes
the heart contract more often in order to maintain a safe stroke beat.
The heat produced from the heart increases your core temperature and mechanism,
which is triggered to encourage evaporation. Eventually when it is all
evaporated this condition becomes anhydrous. The fruit process of dehydration
is similar to that of the mammals because it follows the same happenings.
Hydration is a chemical compound made of a definite amount of water and
other substances. The evaporation of sweat during exercise enables us to
maintain a safe core body temperature. As a mammal becomes more fit they
will sweat more. This means that they will sweat sooner, for longer periods,
and will sweat over a greater area of body. Sweat losses reduce the blood
volume, which in turn, reduces the sodium concentration of blood. These
physiologic changes stimulate the brain to trigger thirst. Both men and
women exhibit a wide range of sweat responses and sweat rates.
Sweat contains minerals such as sodium, potassium, and chloride, in
addition to small amounts of other electrolytes. The fluid lost in dehydration
decreases the overall blood volume. This requires the heart to contract
more frequently and forcefully. There is no correlation between a personís
age and how much they sweat. There is, however a correlation between fitness
level and sweating responses, and the acclimation to heat. As work occurs,
often via muscle contractions are generated. As the heat increases the
core body temperature the sweat mechanism is triggered to encourage evaporation
and to help cool the body down.
When fruit is presented to heat the water molecules will gradually lose
water and eventually dry up. Most fruits contain approximately 75% water
and will spoil fairly quickly. In order to prevent spoilage the use of
Osmotic dehydration is required. Osmotic dehydration can remove up to 50%
of the fruits water level, most likely preventing quick spoilage. Osmotic
dehydration has been around for more than 20 years being conducted by single
unit operators, engineering aspects, industrial applicators, and technology
economy runners. The main reason that the Osmotic dehydrator was put to
use was to improve the food quality, and increase the economies potential.
The orange is the most popular citrus fruit. It is known in the scientific
world to be the Hesperidium. A Hesperidium is a citrus fruit that has a
thick leathery rind with segmented pulp. The orange is valued for its delicious
juice and its high content of vitamin C. Sixty-five million tons of orange
is harvested throughout the world each year. Oranges grown in the United
States are processed into frozen concentrated beverages. The orange provides
quick energy, which is given off from the edible seed structure inside.
The apple is the most popular pome fruit known to this day. Its firm, fleshy,
structure is received straight from a flower. The Ancient Greeks first
grew the apple in 300 B.C. Later the Ancient Romans brought with them to
England apple seeds. They planted these seeds and unfortunately the Indians
stole the apple trees, straight out of the ground. John Chapman (1774-1845)
distributed seeds within the Indian village and was later called Johnny
Banana is a nourishing fruit that grows in tropics and is popular throughout
the world. People in the United States of America eat about 11 million
bananas annually. The banana is rich in carbohydrates and also contains
phosphorus potassium, and vitamin A and vitamin D. The banana is known
for it sweet flavor and smooth yellowish skin. The Dwarf Cavendish, Williams,
and Grand Nain are other popular varieties of the banana. Other countries
take interests in the skin of the Red Jamaican because it is so thin that
it is only accessible in the tropical areas. Bananas grow in hot damp climates
and then thrive in rich, sandy loam soil that provides drainage abilities.
The banana was first raised in Asia but is now raised in the tropics
of Eastern and Western hemispheres. In 1860 the people in the Tropics ate
bananas fairly often. Later the Merchants in Europe and the United States
realized that exporting bananas could be a good profit, so they built a
way of transportation. In 1890 the first firms were expanded and later
had been replaced by international corporations. They controlled over $400
million world banana trades. Then in 1974, to balance the power between
the two corporations they formed a banana growing country, which formed
a Union of Banana Exporting. Finally in 1984 they together established
an International Network for improvement of plantation.
The Grape Fruit is a large round citrus fruit that everybody in the West
Indies all enjoys. In the West Indies they also drink the somewhat bitter
tartness within the grape fruit. The Grape fruit received its name from
some of the clusters that they produce. The United States produce
45% of the worlds Grape fruit. We harvest 4.25 billion pounds of fruit
yearly. The Grape fruit is said to originate in the West Indies and then
in the early 1700ís scientists believed it had developed as a natural hybrid
of the shaddock, or pummelo, a citrus fruit of the Southeastern, Asia.
It was first planted in Florida in about 1820. By the 1900ís fruit was
being produced and shipped throughout the United States.
Fruit is an important part of a healthy diet. Keeping fruit fresh and properly
hydrated makes it more appetizing and nutritious. Dehydrating fruit is
a good method of preserving it when refrigeration is not available or adequate.
Barden, John A. "Apple" World Book Encyclopedia. 2002: CD ROM
Beck, Laurence H. "Dehydration" World Book Encyclopedia. 2002: CD ROM
DíAlessandro, Donna and Huth, Lindsay "Dehydration" What is Dehydration.
Janick, Jules "Fruit" World Book Encyclopedia. 2002: CD ROM
Lombardo, Peter V. "Publication of apple slices" Osmotic Dehydration
Marc Le Maguer, John Shi. "Osmotic treatment of foods" Osmotic Dehydration
"Osmotic." Dehydration of fruit. November 25, 2002 http://www.barc.ernet.in/webpages/technology/osmotic.html
Quinn, Elizabeth "Hydration and Dehydration" Sports Medicine Quiz. 2002
Rock, Peter A. "Hydration" World Book Encyclopedia. 2001: CD ROM
Wardowski, Wilfred F. "Orange" Microsoft Encarta Encyclopedia. 2002: CD
I would like to thank the following people:
My mother, for picking me up after late science classes and helping me
with phrases of the experiment.
My brother, for helping me pick out the fruit.
My Advanced Science teacher, for hosting after school science classes allowing
me to complete my project and for loaning me the technology to make this
My immediate science teacher, for allowing me to use the classroom computers
during class time.
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