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B17
Monosodium Glutamate: The Distinct Flavor
The food industry is a business of mass production and consumption. Plants and animals
that people use for food are grown in bulk on farmlands nationwide, and processed later at large
factories. It is common knowledge that some of the most popular snack foods come along with a
long list of ingredients. The explanation for a variety of chemicals in food is for the enhancement
of color, texture, flavor, and shelf life [Might be better worded as: The variety of chemicals
found in food help enhance the color, texture, flavor and shelf life of the food]. It is important for
a company to extend the longevity of a product’s life in a store, before being bought and
consumed. There are hundreds of food additives such as ascorbic acid, aspartame, and xantham
gum. Another common food additive for the general population is monosodium glutamate
otherwise known as MSG. Yet, most people do not fully understand what MSG really is. It is
often an ingredient targeted as the cause of “Chinese Restaurant Syndrome” [Describe what
Chinese restaurant syndrome is]. This leads to the mystery of what is MSG, and what does it do
to the human body? Is it helpful, is it harmful, and what do we know about it? The best place to
begin would be with MSG’s discovery.
MSG, also known as sodium glutamate, is a sodium salt of the naturally abundant
glutamic acid. It is also a non-essential amino acid meaning that it can be synthesized within the
human body [These two sentences don’t really have anything to do with the discovery of MSG].
The first encounter of MSG started with a University of Tokyo professor named Kikunae Ikeda
in 1908 [Flows better with the previous paragraph if this is your beginning sentence]. He was
interested in the pleasant flavor of the soup, also known as the umami taste. Umami flavor is
described differently than the other 4 tastes: sweet, salty, bitter, and sour. Umami is a “meaty”
but mild flavor. He was able to extract L-glutamic acid from a seaweed soup broth and conclude
that as the umami component. [Citation needed]
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Professor Kikunae Ikeda
In an attempt to study other L-glutamic acid salts, Ikeda tried [tried what?] calcium,
magnesium, potassium, and ammonium. He settled with sodium because it was the most soluble,
easiest to crystalize, and best tasting. [Explain how his discoveries with sodium led him to
produce MSG] Ikeda then went on to patent and start producing MSG. With help from Ikeda,
Ajinomoto, a MSG producing company, was founded by Saburosuke and Chuji Suzuki in 1909.
Today, industrial manufacturers produce MSG as a flavor enhancer because it balances the
overall taste of products. Ajinomoto USA has also formed and to this day they still contribute in
worldwide MSG production. [Citation needed]
Today, MSG is produced from the fermentation of starch, sugar beets, sugar cane, or
molasses. The [MSG production? Fermentation?] process was discovered back in the early 1950s
when E.coli was observed to excrete amino acids and yield of L-glutamic acid could be
improved through the addition of ammonium salts. From that information, it was not long until
Cornynebacterium glutamicum formed strictly (S)-glutamic acid, MSG, from ammonia and
carbohydrates in vegetables [1]. The reaction is as follows:
C12H22O11 (carbohydrate) + 3O2 + 2NH3  2C5H9O4N (glutamic acid) + 2CO2 + 5H2O
The yield of (S)-glutamic acid in the culture is also influenced by its ability to escape the
plant cell membrane. In high levels of biotin, a vitamin for cell growth, the cell membrane
prevents the passage of glutamate. Both beets and molasses are high in biotin, which means they
were not used until biotin inhibiting agents were discovered [1]. The nitrogen source is added to
the culture through ammonium salts, urea, or pure ammonia gas. Ammonia gas is preferred
because of its ability to maintain the pH at physiological levels. The fermentation process is
aerobic, and thus uses oxygen. Keeping control of the temperature and oxygen levels, the
fermentation runs about 35-45 hours. At the end, the fermented broth is centrifuged to remove
any solids, and the supernatant is kept for further purification. The broth has its pH adjusted to
3.2, to reach the isoelectric point of glutamic acid. The isoelectric point is simply the pH where
the amino acid has no electrical charge. Then crystallization is induced with seed crystals to get
the resulting (S)-glutamic acid. Sodium then can be added to keep the salt neutralized. The
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advantage of this method is that the yield is around 60%, and it only produces the desired (S)
enantiomer of glutamic acid. The (R) enantiomer is not desired because it is tasteless. MSG
powder will be white and odorless, and dissociates into glutamate and sodium in water. The
molecular composition of MSG is C5H8NO4Na with a molar mass of 169.111 g/mol. The
solubility in water is 74 g/100mL. As a flavor, MSG also enhances other taste-active compounds
when combined with meat, fish, and vegetables. For example, this effect is seen in MSG reacting
with disodium inosinate and disodium guanylate. The substances are tasteless in the absence of
MSG, but upon its addition MSG will produce a flavor 6-8 times stronger than expected [1]. It
will improve the taste of most food, but excessive amounts will make food unpleasant. MSG has
also been used to help reduce the intake of sodium chloride. It is capable of improving flavors
even if the salt chloride content has been reduced up to 30% of a standard amount. [might want
to put the production of MSG section of the essay at the end of the paper to make it more
interesting]
MSG from manufacturers Ajinomoto
The most controversial subject about MSG has been whether or not it is safe as a food
additive. The “Chinese Restaurant Syndrome” was created when many people described several
unpleasant symptoms after consuming take out Chinese food. These symptoms include
numbness, chest pain, headache, nausea, and drowsiness. Yet, the amount of MSG necessary to
lethally kill a person is around 15-18 g/kg. This is a large amount and would not be consumed
accidentally by any normal human. In 1959, the U.S. FDA labeled MSG as “Generally
Recognized as Safe” (GRAS). However, there is a small group of people that appear to have an
MSG allergy when exposed to 3 g in the absence of food. The studies on MSG have not
indicated any threat from MSG, but testimonies still report the adverse effects of it. [citations
needed]
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As mentioned, MSG brought forth the term “Chinese Restaurant Syndrome”. This was
studied by Dr. Russell Blaylock, who determined that MSG is an excitotoxin. An excitotoxin is a
chemical that causes a brain cell to become overstimulated. As a result, an influx of calcium ions
will go into the post synaptic cell. The high levels of Ca2+ will activate many cellular degradation
processes eventually leading to the cell death [3]. This gives MSG the potential to increase
permanent damage to the brain and nervous system. Neurological diseases such as Alzheimer’s,
Parkinson’s, and Lou Gehrig’s also have a higher reported chance [4]. The FDA has stated that
the function of glutamate receptors have been linked with neurological diseases in laboratory
animals [4]. Glutamate receptors are located in neuronal cells, with most of them residing in the
brain. Glutamate is used as a neurotransmitter responsible for the excitation of neurons. These
processes are important for neural communication, memory formation, and learning [5].
Glutamate receptors are also found in heart tissue and in the heart’s electrical conduction system
[2]. Yet, the FDA dismisses the fact that consuming MSG will contribute to any neurological
problems through lack of evidence. There is also the theory of experiencing lower health with a
high level of MSG in the diet. People affected by MSG have also been linked to obesity, eye
damage, headaches, fatigue, and depression.
The reason that these food companies do not remove MSG from their products is for the
sake of their sales. They need to keep MSG so products are not compromised and to avoid
getting caught when they try relabeling MSG. They will hide it by using obscure ingredients that
contain MSG instead. [Another view?] is that MSG is not the culprit, but rather the high fat
content of food that it is in. People also argue that all substances are poisons depending on the
amount that a person ingests. This proves that table salt is no more dangerous than MSG at small
levels; however, it is very toxic at high levels. Finally, people also question whether there is a
difference between natural L-glutamic acid and processed L-glutamate. They are technically the
same, except that L-glutamic acid produced commercially is subject to impurities such as Dglutamic acid, and pyroglutamic acid. These impurities might also be part of the reason that
MSG is harmful to people. [citation needed]
Therefore, the history of MSG is a continuous debate of whether food companies rely on
it too much for flavor. There is the side arguing that MSG has been the [cause of] many medical
conditions. Then, there is the other side that concludes no finite evidence of MSG [has been]
linked to headaches, numbness, chest pain, nausea, and heart problems. However, the FDA has
confirmed that some people are allergic to it. It has also yet to be determined why natural
glutamate in cheese produces no side effects, whereas commercially produced MSG does. The
truth appears to be conclusive that MSG is generally harmless, but should be consumed in
moderation. That is easier said than done, because when at the store it is surprising how many
items contain MSG or some variant within them.
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[Overall good paper. You might want to rearrange the paragraphs a bit to make the information
flow from one idea to the next]
Works Cited
[1]Ault, Addison. "The Monosodium Glutamate Story: The Commercial Production of MSG and
Other Amino Acids." Journal of Chemical Education 81.3 (2004): 347-55. Print.
[2]Blaylock, Russell L. "Sudden Cardiac Death and Food Excitotoxin Additives by Russell L.
Blaylock, MD." Sudden Cardiac Death and Food Excitotoxin Additives by Russell L. Blaylock,
MD. N.p., n.d. Web. 13 Feb. 2014.
[3]Dubinsky JM (February 1993). "Intracellular calcium levels during the period of delayed
excitotoxicity". J. Neurosci. 13 (2): 623–31
[4]Misner, Bill. "MONOSODIUM GLUTAMATE (MSG), GLUTAMIC ACID (Glutamate),
GLUTAMINE REVIEW." (n.d.): n. pag. | Hammer Nutrition. Web. 12 Feb. 2014.
[5]Olney, JW. "Excitotoxins in Foods." Neurotoxicology (1994): 535-44. Review Of: Excitotoxins:
The Taste That Kills | American Nutrition Association. Web. 13 Feb. 2014.