By: Mara L.
| Abstract | Purpose |
| Hypothesis | Experiment Design |
| Materials | Procedures |
| Research Report | Results |
| Conclusion | Bibliography |
|
|
|
|
Abstract
The purpose of this experiment was to determine whether irradiation
had an effect on the nutritive value of beef.
My first hypothesis was that irradiated and nonirradiated beef would have the same amount protein and nitrogen. My second hypothesis was that the lipids in irradiated beef would be less than nonirradiated beef.
The manipulated variable in this experiment was the irradiated ground beef.
The responding variables in this experiment were the protein, nitrogen, and lipid content in the beef patties.
To measure the responding variables, the protein and nitrogen was found by using a Licos machine. Protein was measured by percentage and nitrogen was unknown quantity. The lipids of the beef patties was measured by mL through sodium hydroxide.
The constants in this experiment were:
If I were to conduct this experiment again, I would have more trials in the experiment, have more nutrients to test, use more irradiation sources, have more types of meat.
Purpose
The purpose of this experiment is to determine whether irradiation
has an effect on the nutritive value of beef. The nutritional analysis
will be made upon the content of protein in beef, which include nitrogen,
and the content of lipids the beef contains.
I became interested in this project when searching the Internet for science projects that include radiation. I came upon a website that included food irradiation and what the consumer thought about it. I thought that by conducting a science project that included food irradiation would help me understand the advantages and disadvantages of food irradiation, as well as some consumers.
The information gained within this experiment will benefit food scientists who are currently conducting research on the nutritive loss of irradiated meats. It will also benefit consumers who will be able to understand that irradiated meat is safe and more healthier for them than nonirradiated meat.
Hypothesis
My first hypothesis is that the irradiated beef and nonirradiated
beef will have the same amount protein and nitrogen level of nutrients.
I base this hypothesis on a personal interview with Barry Swanson, a professor at WSU who said, “Irradiation is a very high electromagnetic energy that will randomly strike biopolymers in exposed foods. The protein in meta may break down on exposure to irradiation, but the broken parts of the protein will remain in the food.”
My second hypothesis is that the nutritional value of lipids in the irradiated beef will be less than in nonirradiated beef.
I base this hypothesis on “Irradiation may generally act destructively on unsaturated fatty acids,” which can be found in the book called Safety of Irradiated Foods
Experiment Design
The manipulated variable in this experiment is the irradiated ground
beef patties.
The responding variables in this experiment are the protein content and nitrogen content in the beef patties, and the lipid content in the beef patties.
To measure the responding variables, the protein content will be found by percentages through a Licos machine. The nitrogen content of the beef patties will also be found by using the Licos machine, but the quantity label will be unknown. The lipid content of the beef patties will be measured by mL through sodium hydroxide.
The constants in this experiment are:
|
|
Item Description |
|
|
Nonirradiated Ground Beef Patty |
|
|
Schwann's Irradiated Ground Beef Patty |
|
|
Licos Machine |
|
|
Aluminum Containers (Part of the Licos Machine) |
|
|
Electronic Balances |
|
|
40mL Beakers |
|
|
125mL Flourence Flasks |
|
|
Spatula |
|
|
Stirrers |
|
|
Filter |
|
|
Clamp |
|
|
Burrette Stand |
|
|
Pippette |
|
|
Hexane |
|
|
Isobutyle Alcohol |
|
|
Sodium Hydroxide |
|
|
Sulfuric Acid |
Procedures
Part 1: Setting Up the Licos Machine
1. Open up the computer program for the Licos machine.
2. For the first three test group, label them “rad”. This will be the
irradiated beef
patty.
3. For the second three test groups, label them “nonrad”. This will
indicate that this
beef patty does not contain irradiation.
4. Under the protein factor, label 6.25 grams for each test group.
5. Under sample moisture, label 55.00 percent for each test group.
Part 2: Protein and Nitrogen Content
1. Take a small sample of the nonirradiated beef patty
and place it in a 40 mL
beaker.
2. Mix it by itself for about 2 minutes so the proteins
can be balanced out between
the beef.
3. Turn on the electronic balance and the small aluminum
container on top of it.
4. Balance out the electronic balance and take the aluminum
container off.
5. Place about .16 grams of the nonirradiated beef patty
from the beaker onto the
small aluminum container with
a small spatula.
6. Mass the aluminum container with the nonirradiated
beef patty on the electronic
beam.
7. Record the mass of the nonirradiated beef into the
computer program for the
Licos machine under mass.
8. Now, place the little aluminum container into one of
the open slots on the Licos
machine.
9. Repeat steps 3-8 for the proceeding 2 nonirradiated
test groups.
10. Repeat steps 1-2, but instead of using part of the nonirradiated
beef patty, use
part of the irradiated beef patty.
11. Repeat steps 3-8 for the irradiated test trial of the irradiated
beef patty in the
beaker.
12. Once all the test groups (nonirradiated and irradiated beef)
are placed in open
slots on the Licos machine, press
the analyze button on the machine.
13. The Licos machine will then analyze the nutritional content
of proteins and
nitrogens found within the meat
by burning it.
14. Once the Licos machine has analyzed the protein and nitrogen
content of one
test trial, it will record it
on the computer program. To read the protein and
nitrogen content of the sample,
look under Protein percentage and
Nitrogen. Record the information
onto your data.
15. Repeat step 14 for the remaining test trials.
Part 3: Titration of the Lipids
1. Get four 40mL beakers and label them from 1-4. Two
of the four beakers will
contain irradiated beef and the
remaining two will contain nonirradiated beef.
2. Take a 40mL beaker and place it on top of the electronic
balance.
3. Balance out the electronic balance so it read 0 grams
with the beaker on top of it.
4. Place about 5 grams of nonirradiated beef into
the 40mL beaker with a small
spatula.
5. This beaker will be label number 1.
6. Repeat steps 2-5 for the following:
1 more beaker with nonirradiated
beef. This beaker will be labeled number 2.
2 beakers with irradiated
beef. These beakers will be labeled number 3 & 4.
7. Take the four beakers and place them on top of the
counter.
8. Place about 25mL of hexane into each of the four
40mL beakers that contain
beef.
9. Mix the hexane with the beef in each beaker for about
5 minutes each, so the fat
in it can be exposed out of the
beef.
10. Take four 125mL flourence flasks and label them 1-4.
11. Take beaker number 1, which is nonirradiated, and drain the
hexane from the
beef into flourence flask number
1.
12. Dispose the remaining beef and set the beaker aside.
13. Repeat steps number 11-12 by the following:
Beaker number 2 drained in flourence
flask number 2 etc.
14. Take a clean flourence flask and make a solution of the following:
A. Place 25mL of hexane
with 50mL of isobutyl alcohol and two drops, which
equal about 1mL and is the base, of sulfuric acid and mix it together in
the
flourence flask.
B. In the pipette place
some sodium hydroxide in it.
C. Then, place the flourence flask
under the pipette and slowly add some sodium
hydroxide into the mixed solution. Keep the solution constantly stirred.
D. When the solution changes
to a pink/purple color, then your solution will be
ready and the solvent will be about 1.1mL.
E. This solution will be
used as a sample color of how the titration of the lipids
of the beef should be.
15. Take flourence flask number 1 and place 50mL of isobutyl
alcohol into the
solution and two drops of the
base, which is sulfuric acid.
16. Repeat step number 15 for the remaining 3 flourence flasks.
17. Place 125mL of sodium hydroxide into the pipette.
18. Take flourence flask number 1 and place it under the pipette
on the burette
stand.
19. Record the starting point of the sodium hydroxide in the
pipette.
20. While stirring the solution in the flourence flask, release
some sodium hydroxide
into the flourence flask and mix
with the solution.
21. Continue step number 20 until the solution changes into a
pink/purple solution
like your example in step number
14.
22. Once the solution has changed into a pink/purple solution,
record the amount of
sodium hydroxide it took to change
from the start to finish.
23. Set the flourence flask aside.
24. Repeat steps number 19-23 for flourence flask numbers 2-4.
25. To find the amount of sodium hydroxide each sample took,
subtract the starting
point of the sodium hydroxide
from the finish point and that is the amount of
lipids the sample beef had (both
for irradiated and nonirradiate).
FOOD IRRADIATION
Historical Background
The irradiation process has been used in many other countries other
than the U.S. But in the U.S., the irradiation process was used to disinfect
spices and herbs and to sterilize food for astronauts or patients with
immune diseases. In the U.S., irradiation has been approved for use in
foods since 1963 for the control of insects and parasites in wheat. In
1984, the FDA issued a permit in using ionizing radiation for fresh fruits
and vegetables to disinfect the food. In July of 1986, the FDA also approved
for ionizing radiation to be uysed in pork (up to .3 kGy). The FDA also
approved that food being irradiated mest be labeled.
Consumer Acceptance
Many consumers fear food irradiation as a whole because when
they hear the word "food irradiation" they constantly thibk about nuclear
radiation or nuclear weapons. Some do not understand that irradiated food
cannot become radioactive. Others are afraid if accidents that may occur
in irradiation facilities of ood to the workers or their community. But
as soon as the consumer starts accepting food irradiation, the sooner the
U.S. will be able to produce safer food.
Advantages and Disadvantages
As the society begins to learn about food irradiation, many concerns
have come up. Society wants to know the advantages and disadvantages of
using food irradiation to sterilize food. Advantages of using food
irradiation include:
MEAT
Beef Cattle (beef)
Beef cattle have been bred primarily for the production of meat, and
many breed have been developed for certain conditions. The major
breeds of beef cattle in North America are Angus, Hereford, Polled
Hereford, Charolais, Shorthorn, Santa Gertrudis, Brahman, Brangus, and
Red Angus.
NUTRIENTS
Amino Acids
Amino acids are compounds that contain amino (ËNH2) and carboxyl
(ËCOOH) groups. Of these acids, twenty of them can be found
in proteins. These twenty acids can be constructed into one general
formula. The formula shows that the amino and carboxyl acid are both
attached to a single carbon atom. A variable (R) is attached to the
single carbon atom. In the R variable, all twenty amino acids can
be found, but differ from one another. In the simplest of the acids, the
R variable consists of a single hydrogen atom.
Proteins
Chains of rich chemicals are compounds of a protein which are called
amino acids. Proteins are essentially made by amino acids. When a
living cell makes proteins, the carboxyl acid of one amino acid links to
another amino group of a peptide bond. The carboxyl group of a second
amino acid is linked to a third amino group and so on, until the chain
is produced. The chainlike molecule, which can consist fifty to several
subunits, is called a polypeptide. A protein may be formed from a
polypeptide chain, or from several polypeptides. Each protein is formed
by a precise set of instructions within the nucleic acid. The assembly
of proteins take place in the cytoplasm of a cell. It is the body’s most
plentiful nutrient other than water and fat. Humans have an estimated
thirty thousand different proteins. About two percent of those proteins
are adequately described. Proteins serve primarily to build and maintain
cells, but when it is broken down, it can provide energy.
Most plants and microorganisms are able to use inorganic compounds to make the amino acids needed for their body intake. But animals cannot and must obtain the amino acids needed through the food they eat everyday. These amino acids are called Essential amino acids. For humans this may include lysine, tryptophan, valine, histidine, leucine, isoleucine, phenylalanine, threonine, methionine, and arginine. But these acids can be found in protein-rich foods from animal sources, as well as some plant sources.
The human body cannot make certain types of amino acids, therefore protein must be taken by the foods eaten. Protein helps to grow and replace certain body tissues in the human body. Besides proteins helping the body function in growth and maintenence, proteins are also responsible for muscle contraction. The digestive enzymes are proteins, the antibodies of the immune system are proteins, and proteins also carry vital substances throughout the body. Proteins also carry all the hereditary characteristics in the form of genes. For proper nutrition, our body should obtain a twenty percent diet of proteins.
Extraction of Nutrients
There are many methods of extraction of nutrients. They can be from
the most complex, which include the Djehal techniques, to the most simplest,
which is by using a Licos machine. No matter how hard the situation may
be, their is always a way of analyzing nutrients. The Djehal technique
is primarily used, but is extremely long. Before the Licos machine came
about, the Djehal technique was used a lot. The process takes several days
and long hours. But when the Licos machine came about, the long days and
hours changed to sweet minutes and seconds. No method is wrong or right
though.
Results
The original purpose of this experiment was to determine whether irradiation
has an effect on the nutritive value of beef. The nutritional analysis
will be made upon the content of protein in beef, which include nitrogen,
and the content of lipids the beef contains. The results of this experiment
indicate that irradiated beef has an average percentage higher in protein
than nonirradiated beef. For the nitrogen, the irradiated beef seemed to
have a bit more than the nonirradiated beef as well. The results also indicate
that the lipids were greater in the nonirradiated beef than the irradiated
beef.
Protein/Nitrogen Results for Irradiated Beef
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Protein/Nitrogen Results for Nonirradiated Beef
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Lipid Results for Irradiated Beef
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Lipid Results for Nonirradiated Beef
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Conclusion
My first hypothesis is that the irradiated beef and nonirradiated
beef will have the same amount protein and nitrogen level of nutrients.
My second hypothesis is that the nutritional value of lipids in the irradiated beef will be less than in nonirradiated beef.
The results indicate that my first hypothesis should be rejected. The irradiated beef had more proteins than the nonirradiated beef. Also, the irradiated beef had more nitrogen content than the nonirradiated beef as well. The second hypothesis of this experiment should be accepted. The irradiated beef had less lipids than nonirradiated beef.
The usefulness of my findings will help consumers understand that irradiated beef is much safer than nonirradiated beef. This experiment will also help food scientists acknowledge the nutritional analysis of this experiment in the amount of nutrient loss between the protein level and lipid level of nonirradiated and irradiated beef.
New question raised during this experiment were if the beef were irradiated a few days before the experimentation, would that change the nutritional value of proteins and lipids within the beef? Another question would be if I were to find the nutritional value of other meats, or maybe even other types of food, would that affect the nutritional value of the substance? Finally, a third question would be if I were to test more nutrients other than protein or lipids, would that affect those nutritional values in the food?
If I were to conduct this experiment again, I would have more trials in the experiment. I would also start the experiment sooner and have more nutrients to test. Along with that, I would use more than one irradiation source and irradiate some of the meat myself. I would have more nonirradiated samples, and finally I would have more than one type of meat. I would also like to have some fruits to test their vitamins and minerals.
Possible scientific errors that could have occurred during the experimentation include that the beef did not come from the same cow, therefore one could have had more proteins or lipid content than the other. Another possible scientific error was that the Licos machine could have read the nitrogen and protein levels wrong. A third possible scientific error was that when titrating the beef to find the lipids, it was not set for the proper amount of time.
Bibliography
“Amino Acids.” Encarta 98 Encyclopedia. CD-ROM. N.p.: Microsoft
Corporation, 1997. N. pag.
“Beef Cattle.” Encarta 98 Encyclopedia. CD-ROM. N.p.: Microsoft
Corporation, 1997. N. pag.
Bettelheim, Frederick A., William H. Brown, and Jerry March. Introduction
to General, Organic, and Biochemistry. Ed. John Vondeling and Frank
Messina. 6th. Ed. Philadelphia: Emily Barrosse,
2001.
Coon, Julius M., Josephson, Edward S., and Wierbicki Eugen. Are
We Irrational About Irradiation?. 2-9.
Diehl, J.F. Safety of Irradiated Food. Ed. Marcel Dekker, Inc.
New York: Basel, 1990.
“Dishing Up Gamma Rays,” Newsweek.January 1992. 52-56.
Eisle, Dr. Tom. Telephone Interview. 6 Dec. 2001.
“Food and Nutrition.” Compton's Encyclopedia. Chicago: Division
of Encyclopedia Britannica, Inc., 1988. 275-279.
Food Irradiation: Solution or Threat? 19 June 1999. IOCU-GPCU.
3 Dec. 2001 <http://www.consumerinternational.org/campaigns/irradiation/irrad3.html>.
Hedrick, Harold B. “Meat.” Compton's Encyclopedia. Chicago:
Division of Encyclopedia Britannica, Inc., 1988. 246-247.
Murphy, Mark. “Re: Can You Help A Student Out?” Email to the author.
17 Dec. 2001.
Newsome, Dr. Rosetta L. “IonizingEnerggy in Food Processing and Pest
Control.” Cast. July 1986. 100-101.
“Nutrients.” Encarta 98 Encyclopedia. CD-ROM. N.p.: Microsoft
Corporation, 1997. N. pag.
“Nutrition.” The New Encylopedia Britannica. Ed: Philip Goetz.
Chicago: Encyclopedia Britannica, Inc., 1988. 992-993.
Olson, Dennis G. Irradiation of Food. January 1998.
“Proteins.” Encarta 98 Encyclopeia. CD-ROM. N.p.: Microsoft
Incorporation, 1997. N. pag.
Starr, Cecie , and Ralph Taggart. Biology: The Unity and Diversity
of Life. Ed. Karen Stough and Jamee Rae. 9th. Ed.
United States: Jack C. Carey, 2001.
Stiles, Dennis L. “FW: A Student Who Needs Help!” Email to the author.
10 Jan. 2002.
Swanson, Dr. Barry. “Science Project Request.” Email to the author.
2 Feb. 2002.
Zurer, Pamela S. “Food Irradiation: A Technology at a Turning Point.”
C&EN
Washington. May 5, 1986. 46-56.