Vitamin C Amount Estimation
Vitamin C (ascorbic acid) is a very
important vitamin to the body. Vitamin C
promotes healthy teeth and gums,
helps absorption of iron, aids in maintenance
of normal connective tissue,
promotes wound healing, and helps boost the immune
system. With vitamin C
being such a useful substance to our bodies, finding good
sources of vitamin
C is important. Many people today rely on vitamin supplement
tablets. But
fruit juices, vitamin-supplemented drinks, or vitamin supplemented
foods may
contain just as much vitamin C as a supplement tablet. Which one is
better
though, commercially sold drinks or fresh fruit juices? This was the
research
question: Are commercially sold and popularly consumed juices (in
Japan)
a good substitute fro fresh fruits in terms of dietary vitamin C? What
this
experiment sought to find out was exactly what kind of drink was better
in
terms of dietary vitamin C. The juices were titrated into a set amount of
DCPIP
and measuring how many millilitres it took for the DCPIP to turn from
blue to
clear. The hypothesis was that fresh fruit juices should contain more
vitamin C
since they had not been heat treated and probably had spent less
time on a shelf
or being transported than commercially sod drinks. This is
important since
vitamin C is heat labile. This means that vitamin C is
susceptible to change and
unstable or that the vitamin C can break down
easily if exposed to high
temperatures or is kept for a long time on a shelf.
The experiment and results
showed that vitamin C is more abundant in fresh
fruit juices. This was true for
all the juices tested except for lemon.
Therefore, it is safe to say that fresh
fruit juices tend to contain more
vitamin C than commercially bought juices.
Introduction The body needs a
good balance of foods, which must contain
carbohydrates, proteins, and fats
along with mineral salts, water, fibre, and
vitamins. All of these are
required in different amounts according to different
people. However, there
are recommended daily allowances. For example, the
recommended daily
allowance for vitamin C is 60mg. Vitamins are easily absorbed
into the
bloodstream from the gut. A diet lacking in any particular vitamin will
lead
to a deficiency disease. Such diseases are rickets that is caused by lack
of
vitamin D, and night blindness that is caused by lack of vitamin A.
However,
these can be remedied by using vitamin supplements if the dietary
intake is
inadequate. The aim of the experiment was to see the difference of
vitamin C
content between fresh fruit juices and commercially sold and
popularly consumed
juices (in Japan) a good substitute for fresh fruits in
terms of dietary vitamin
C? This research question was established
because in the modern day and age
people are too busy, especially in winter,
to stock up on fresh fruit and many
people rely on commercially sold drinks
as a source of vitamins. However,
vitamin C, in particular, is known to be
labile and therefore likely to be
absent from a cooked food diet. In
temperate climates, such as Japan or Europe,
people ear fresh fruits in
summer, but eat tinned, preserved, or cooked foods in
the winter. The latter
being more susceptible to heat, possibly breaking down
the amount of vitamin
C in them. This experiment tested for the vitamin C
content in fresh fruit
juices and commercially sold drinks. This experiment was
conducted mostly on
citrus fruits because vitamin C is said to be abundant in
citrus fruits. The
experiment was also performed on non-citrus fruits. The
experiment was
performed on these two types of fruit drinks because vitamin C
contributes to
maintaining a healthy body, especially during the winter, when
citrus fruits
are not in season. AS a result, the amount of vitamin C found in
each type of
juice would be essential in knowing what drinks to choose during
the winter
to provide the most or the optimum amount of vitamin C. Using
this
information, the following hypothesis was formed. Since vitamin C is
labile
(meaning susceptible to change and unstable), the commercially sold
juices,
which have most likely been heat treated and stored in various
conditions for
various periods of time, should have lower vitamin C content
than fresh fruit
juices. The commercially sold juices would have most likely
been exposed to the
conditions leading to the deterioration in the content of
vitamin C. In this
experiment the independent variables were the juices that
were being tested for
their vitamin C content. The volume of each required to
make a standard volume
of DCPIP (dichlorophenolindophenol) change from blue
to clear was measured.1
This was the dependent variable. These juices
were first filtered and then
titrated using a burette. The fixed variable of
the experiment was the amount of
DCPIP in each beaker and the room
temperature. Both of these remained constant
throughout the experiment. The
importance of the room temperature being constant
and not too high is because
otherwise the vitamin C content of any and all the
juices may have been
altered, since vitamin C is heat labile. Moreover, if the
temperature varied,
the measured results might have varied also. The DCPIP was
carefully made to
the concentration of 0.1%. In each case 2 millilitres of DCPIP
was taken. The
amount, 2 millilitres of DCPIP, was chosen because it was not too
much or too
little an amount for the reactions to be seen clearly, without
taking too
much time. Vitamin C was first discovered because of its absence,
during the
age of exploration. Sailors on long sea voyages suffered very often
from
bleeding gums, loosened teeth, and aching joints. These were the symptoms
of
the disease now called scurvy. It is called scurvy because of "the
presence
of scurf’s (or scales) on the skin". It was James Lind that showed
that
scurvy could be cured and prevented by eating "greens, fresh vegetables,
and
ripe fruits". However, it was the Polish biochemist, Casimir Funk, which
named
the missing group vitamines. He named this because he believed that
they
contained an amine group. Vitamines means "life amines". It is from the
word
that we get the word, vitamin. When vitamin C was finally isolated in
1925, it
was given the name ascorbic acid because ascorbic means "no
scurvy".2
Vitamin C has many functions in the body. One of the most
important functions is
as an antioxidant. This means that it helps prevent
oxidation of water-soluble
molecules that could otherwise create radicals,
which may generate cellular
injury, disease, and damage skin cells. It can
also be said that it helps
neuralise or counteract damage to cells caused by
free radicals, which can cause
the aging of skin and damage to different
cells around the body. Indeed,
ascorbic acid (vitamin C) is commonly added to
processed food as an antioxidant.
3 In some roles, vitamin C may act as a
coenzyme, helping a particular enzyme to
do its work, especially where
metallic ions play a role. Where there are two
oxidation states of metals
such as Fe2+ (Iron II) and Fe3+ (Iron III), in the
presence of vitamin C the
reduced form (Fe2+) prevails. For iron-deficiency
anemia, vitamin C helps the
absorption of iron (especially the nonheme or
vegetable-source iron) from the
gastrointestinal tract.4 Specifically, ascorbic
acid works as a coenzyme to
convert proline and lysine to hydoxyproline and
hydroxylysine, both important
to the collagen structure. 5 Vitamin C also helps
in the stimulation of
production of collagen. Collagen is the basis of
connective tissue. It is
found in ligaments, skin, cartilage, vertebral discs,
capillary walls, bones,
and teeth. As a result, vitamin C helps heal wound in
the ligaments, blood
vessels, skin, and cartilage. It also helps prevent hernias
as it protects
the inside part of the disc in the vertebral discs where hernias
may occur.
Vitamin C is also used in skin treatments because it softens the skin
and
prevents or delays the aging of skin.6 It also helps form serotonin which
is
an important brain chemical, it stimulates adrenal function, it aids
in
cholesterol metabolism, helps wounds heal, and helps maintain healthy
blood
vessels.7 In diabetes, vitamin C is commonly used to improve the
utilisation of
blood sugar and thereby reduce it, but there is no clear
evidence that regular
vitamin C usage alone can prevent diabetes.8 There are
some preliminary reports
that ascorbic acid may help prevent cataract
formation (probably through its
antioxidant effect) and may be helpful in the
prevention and treatment of
glaucoma, as well as certain cases of male
infertility caused from the clumping
together of sperm, which decreases sperm
function. Ascorbic acid is also said to
act as a detoxifier and may reduce
the side effects of drugs such as cortisone,
aspirin, and insulin; it may
also reduce the toxicity of the heavy metals lead,
mercury, and arsenic,
either by controlling Oxidation State or by facilitating
excretion. There are
other proposed functions for vitamin C, but they remain
controversial. For
example, it is said that it aids in the production of
interferon, which
stimulates the immune system, that it is an antihistamine and
therefore
prevents or lessens the affects of allergies, and it may help prevent
certain
forms of cancer. In short, vitamin C helps prevent scurvy, promotes
healthy
teeth and gums, helps absorption of iron, aids in maintenance of
normal
connective tissue, promotes wound healing, and helps boost the immune
system.
However, vitamin C is also a natural laxative and may help with
constipation
problems. In fact, the main side effect of too much vitamin C
intake is
diarrhea. However, this will not happen if you go over the
recommended daily
allowance (RDA). For this side effect to occur there would
have to be a very
high consumption of vitamin C, very fast because it is a
water soluble
molecule.9 Vitamin C is an important substance in the body.
This is why it is
vital that we take in the right amount of vitamin C by
eating or drinking the
substances that supply us with it. Materials · Fresh
grapefruit · Fresh lemon
· Fresh orange · Fresh pomegranate · Fresh apple ·
Fresh mikan (tangerine)
· Bottle of C100 Vitamin Lemon drink · Can of
Nichirei Acerola drink · Bottle
of Sawayaka apple juice · Carton of Zakuro
(pomegranate) Water drink · Carton
of grapefruit juice · Carton of Dole
orange juice · Tin of Sanyo mikan ·
Carton of Ringo No Oishii Mizu
(Delicious Apple Water) · Knife · Cutting board
· Blender · Lemon squeezer
Filter · Distilled water · Burette · DCPIP
(0.1%) solution · Funnel · White
marble tile · Paper napkins · 14 beakers ·
6M hydrochloric acid ·
Electronic scales · Spatula · Pipette Procedures An
amount of 0.5g of DCPIP
(dichlorophenolindophenol) powder was measured on an
electronic scale. Next,
500ml of distilled water were then mixed together to
form 500ml of 0.1% DCPIP
solution, which was stored in a dark bottle. The
solution was a dark blue
colour. DCPIP is used for the testing of vitamin C.
When tested for
vitamin C, a colour change will take place either from blue to
clear, or from
blue to pink to clear. Once the full colour change is observed,
the amount of
solution taken to change it can be recorded. The burette was
cleaned
thoroughly using hydrochloric acid. The acid was poured in gently so as
not
to spill while the burette was slowly rotated over a sink. Once this
was
finished, water was run down the sink so the acid would be diluted and be
less
harmful to the pipe system. Distilled water was then poured down the
burette to
make sure the acid was fully rinsed out. The grapefruit had the
juice extracted
from it using a regular lemon squeezer. The squeezer was then
cleaned using
distilled water. The juice was hen filtered using a tea
strainer and then a
filter paper. The juice was collected in a beaker. This
procedure was repeated
with an orange, lemon, and a mikan (tangerine). The
pomegranate was cut in half
and the juice was extracted by squeezing each
half using the hand. This juice
was also filtered in the same fashion as all
the juices. The apple was diced and
put into a blender where it was blended
until it looked like a puree. This was
then filtered and placed into a beaker
like the previous juices. All the juices,
including the commercially sold
ju8ices, were filtered to prevent blockage of
the burette. Next, 16 beakers
were each filled with 2ml of 0.1% DCPIP solution.
The burette was filled
with the fresh grapefruit juice just past the zero line
using a funnel to
pour it into the burette so the juice would go directly into
the burette. The
grapefruit juice was then drained until it came exactly to the
zero line.
Looking at eye level to see if the bottom part of the curvature was
exactly
at zero checked this. The grapefruit juice was slowly dripped into the
beaker
of DCPIP until a clear observation in the colour change was observed.
The
beaker was swirled gently to ensure mixing. It was properly observed, as
a white
tile had been placed under the beaker of DCPIP. This made the colour
change more
clearly visible. The amount of juice taken for a full colour
change to take
place in the beaker containing DCPIP was recorded. The burette
was then cleaned
by pouring distilled water through it twice. The lemon juice
was then poured
into the burette and the mount of lemon juice taken to
observe a clear colour
change in the beaker containing DCPIP was recorded.
The burette was cleaned once
again and the process was repeated with each
fresh fruit juice and commercially
sold drink. Data Chart showing The Amount
of Fruit Juice Needed in ml’s to
Turn DCPIP From Blue To Clear Types of
Juices Amount of commercially sold juices
in ml needed to turn 2ml’s of DCPIP
clear Amount of fresh juices in ml’s
needed to turn 2 ml’s of DCPIP clear
Grapefruit 50+ ml 2.2 ml Lemon 0.13 ml
2.0 ml Orange 2.9 ml 2.3 ml
Pomegranate 50+ ml 11.3 ml Apple 1.4 ml 23.1 ml
Mikan (tangerine) 6.5 ml
2.9 ml The above chart shows how many ml’s of each
juice, both commercially
sold and fresh, it took to turn 2ml’s of DCPIP clear.
All fruits used to
make the fresh fruit juices in the experiment were purchased
fresh so heat
and length of time wouldn’t have affected the vitamin C content
too much. All
the commercially sold juices were bought on the basis of
popularity among
teenager’s in Japan. They were bought to represent the likely
amount of
vitamin C intake that Japanese teenager’s would have during the
winter when
cooked vegetables would lose a lot of their vitamin C content. The
fewer
amounts of millilitres of juice it took to turn DCPIP from blue to clear,
the
larger the amount of vitamin C there was in the drink. In
procuring
commercial fruit juices, it soon became apparent that all was not
what it
seemed. Some were heavily supplemented with vitamin C (e.g. the
commercially
sold lemon drink "C1000 Lemon" and other, while labeled as fruit
juices,
contained only 10% juice!) When the commercially sold lemon drink was
first
measured, the colour changed with a mere 0.1ml of lemon drink, or just
four
drops. So the experiment was repeated with a one in ten dilution of the
lemon
drink, this time giving a reading of 1.3ml. Tinned mikan (tangerine)
juice was
used and juice prepared for other fruits, i.e. the tin juice was
discarded and
the mikan sections squeezed and filtered. The carton of
grapefruit juice was
labeled as containing 20% real fruit juice. This may be
why the amount of ml of
juice it took to turn the DCPIP from blue to clear
was not established. Over
50ml's of this grapefruit juice was titrated
into the beaker containing DCPIP
with little colour change observed. This was
shown as more than 50ml on the bar
chart, but in each case 75ml was run in
without colour change observed. After
the DCPIP was too dilute to read the
colour. The more than 50ml readings should
be interpreted as effectively zero
vitamin C content. The juice prepared with a
fresh grapefruit showed that
there was nearly as much vitamin C content as in
the fresh lemon juice.
Therefore, real grapefruit is high in vitamin C content.
The lemon drink
tested was supposed to provide the daily intake of vitamin C. It
only
contained 10% real fruit juice. This means that vitamin C that was
not
naturally produced was inserted into the drink. This is obvious because
when
compared to the commercially sol lemon juice, the amount of fresh lemon
juice
needed to turn DCPIP from blue to clear was almost five times the mount
of the
commercially sold lemon juice. The commercially sold orange juice
contained 100%
real fruit juice. It is easy to tell that this juice was
either heat treated or
old, as it is 100% as real as the fresh orange juice
made, but it took 0.6 more
ml to turn the DCPIP from blue to clear. The
vitamin C content in the
commercially sold orange juice was probably broken
down a bit by being heat
treated and being in storage and on a shelf for too
long. It is because vitamin
C is heat labile that the vitamin C broke
down under these conditions. The
carton of pomegranate 'water' contained 10%
real juice. More than 50ml of the
pomegranate 'water' were used to measure
the change of DCPIP from blue to clear.
On the bar chart it is shown as
greater than 50ml though. However, this change
was not observed even with
that amount of the drink being used, therefore the
effective vitamin C
content was zero. In the case of fresh pomegranate juice the
change in colour
was hard to observe/measure as the colour of the pomegranate
juice and the
pink stage of DCPIP was similar in colour. The difference in
colour between
the pomegranate juice with the DCPIP pink stage and the
pomegranate juice by
itself was observed better using a white tile beneath the
beaker containing
the DCPIP and a beaker of fresh pomegranate juice was place on
an other white
tile right beside it to make a clearer comparison. The apple
drink (acerola)
contained 10% real fruit juice. The acerola apple is different
from the
common eating apple used in the fresh fruit juice comparison. It is
more
closely related to the crab apple. It was found, after some more
research,
that acerola apples have a very high vitamin C content, more so
than the common
eating apple. Although extra vitamin C may have been
introduced into the drink
[the package label was not helpful], the vitamin C
content was still very high.
It contained twenty times the mount of the
fresh apple juice tested. Another
popular Japanese apple drink called Ringo
No Oishii Mizu (delicious apple water)
was tested for vitamin C content. It
contained 20% real fruit juice made of
apples similar to those used for the
fresh fruit juice tested. With this apple
drink it took 26.9ml before DCPIP
turned clear. The mikan juice extracted from
tinned mikan contained 100% real
fruit juice. Tinned goods are heat treated, and
are normally cooked as part
of the canning process. Thins tend to have longer
shelf and storage lives
too, that would probably account for the decomposition
of vitamin C that gave
the relatively low reading in comparison to the fresh
mikan juice. However,
given the famed lability of vitamin C, the readings for
canned mikan were
surprisingly high and confound the accepted wisdom that
"canned fruit
contains no vitamin C". The graph shows the different
amount of each juice in
millilitres needed to turn DCPIP from blue to clear.
i.e. a lower reading
means more vitamin C. Showing it in graph from makes it
easier to see the
differences between the commercially sold drink in comparison
the fresh fruit
juice. The Amount of Each Drink in Millilitres Needed to Fulfill
the Required
Daily Allowance (RDA) of Vitamin C Commercially Sold Drinks Drink
Amount
of Juice in ml's Needed to Turn 2ml's of DCPIP from blue to clear Amount
of
Juice in ml's Needed to Fulfill the RDA of Vitamin C Lemon (C1000)
0.13ml
8.4ml Orange 2.9ml 187.34ml Apple (acerola) 1.4ml 90.44ml Mikan
6.5ml 419.9ml
Apple ( Oishii Mizu) 26.9ml 1737.74ml The above chart shows
the amount of each
commercially sold drink needed, in millilitres, to fulfill
the required daily
allowance (RDA) of vitamin C, which is 60mg of vitamin C.
This was figured out
because the lemon drink contained 1000mg of vitamin C
and was a bottle of 140ml.
The following equation was then used to figure
out how many millilitres of the
lemon drink would provide a person with the
RDA for vitamin C. The amount of
mg's of vitamin C in drink = The required
daily allowance The amount of ml's of
drink x 1000 = 60 140 x In this
equation x was 8.4. Then 8.4 was divided by 0.13
(the amount of lemon C1000
in ml's needed to turn DCPIP from blue to clear). The
number gotten by doing
this was 64.6. This number was then multiplied by the
amount of juice, in
ml's, needed to turn DCPIP from blue to clear to get the
amount of juice in
ml's needed to fulfill the RDA of vitamin C. This also
applies to the next
chart. For the lemon, orange, and apple (acerola) drink, the
amounts needed
to fulfill the RDA are relatively small. These are amount that
could be
easily consumed without much effort and disgust. For the mikan and
apple
drinks, the amounts needed to fulfill the RDA are sizeable in comparison
to
the lemon, orange, and acerola drinks. Pomegranate and grapefruit juice
were
not included in this chart since the amount of juice needed to turn
DCPIP clear
was more than the 75ml's measured. The amount of apple juice
needed to fulfill
the RDA is impractical for somebody. Drinking almost two
litres of the apple
juice in one day would be highly unlikely. Fresh Fruit
Juices Drink Amount of
Juice in ml's Needed to Turn 2ml's of DCPIP from
blue to clear Amount of Juice
in ml's Needed to Fulfill the RDA of Vitamin C
Lemon 2.0ml 129.2ml Orange 2.3ml
148.58ml Apple 23.1ml 1492.26ml
Grapefruit 2.2ml 142.12ml Pomegranate 11.3ml
729.98ml For the lemon,
orange, mikan, and grapefruit, the amounts needed to
fulfill the RDA are
relatively small. For the apple and pomegranate and apple
juices, the amounts
needed to fulfill the RDA are quite large. It would be
impractical to drink
that much apple juice just to get the RDA of vitamin C. The
juice also tasted
bad. It would be fairly hard or expensive to get enough
pomegranate juice to
fulfill the RDA of vitamin C. However, it is also
impractical to have about
130 millilitres of fresh lemon juice as it is very
sour and not that tasty.
Evaluation From the two types of drinks (commercially
sold drinks and fresh
fruit juices), fresh fruit juices tended to contain more
vitamin C than the
commercially sold juices of the same fruit. The commercially
sold juices that
had a larger vitamin c content than its equivalent fresh fruit
juice were the
lemon juice and the first apple juice tested. The lemon juice
contained a lot
more vitamin C because it was a vitamin C supplement drink for
those in the
winter with colds that don't want to drink the hot cough drinks.
However,
no other commercially sold lemon drink, that wasn't a vitamin C
supplement
drink, was found. The first apple drink tested for vitamin C had
extra
vitamin C added and the type of apple used in the drink had a higher
amount
of vitamin C than the normal apple, which was used for the fresh fruit
juice.
Not all commercially sold drinks had a lower vitamin c content than
their
equivalent fresh fruit juice. This was especially not expected for the
first
apple juice tested. Therefore, the hypothesis: since vitamin C is
labile
(susceptible to change and unstable), the commercially sold juices,
which have
most likely been heat treated and stored in various conditions for
various
periods of time, should have lower vitamin c content than fresh fruit
juices,
was not fully supported. This was due to the fact that assumptions
were made on
the vitamin C content of apples. It was thought that all apples
would have
toughly the same vitamin C content, as a result the expected
measurements were
not as expected. However, this was somewhat remedied by
testing a different
popular apple drink. The results from this test proved to
be like those expected
that were stated in the hypothesis. If the experiment
were to be repeated, the
most likely change would be to get a wider variation
of commercially sold drinks
of the same fruit and, if possible, fresher
fruit. Testing for the vitamin C
content in, for example, three different
commercially sold apple drinks may have
given a more accurate picture of the
vitamin C content in commercially sold
apple drinks. The amount of vitamin C
broken down in the canning or packaging
process, along with the shelf life,
may have also become more apparent. To get
more accurate results, the
experiment should have been done several times. With
all t he results
collected an average should have been calculated to give a more
concise
amount of vitamin C in the drinks tested, but time was limited. Another
thing
that would be good to do if the experiment were repeated would be to test
how
much pure vitamin C (ascorbic acid) it takes to turn DCPIP from blue
to
clear. This was not achieved because there was no ascorbic acid
powder
available. Had it been available, it would have been used as a
control. As a
result, the amount of each juice in millilitres to meet the
recommended daily
allowance of vitamin C was figured out which served a
purpose almost as good as
the control method. In some cases it is conceivable
that the volume of fruit or
commercially sold drinks needed to meet the RDA
would not be practicable. In
short, it took from 50 - 500 millilitres less of
fresh fruit juice than
commercially sold drink to fulfill the RDA of vitamin
C. This is for all fruits
except the lemon and acerola commercially sold
drinks as they had vitamin C
added. The results that were accumulated through
this experiment were nearly all
backed up by the hypothesis, with the
exception of the lemon drink comparison
for reasons stated earlier on in the
paper. The conclusion was made, in answer
to the research question: are
commercially sold and popularly consumed juices
(in Japan) a good substitute
for fresh fruits in terms of dietary vitamin C?
That commercially sold
and popularly consumed juices (in Japan) are not a good
substitute for fresh
fruits (in the form of juices for the purpose of this
experiment). This is
because the vitamin C content for all, except the lemon
juice and the first
apple (acerola) juice tested, was higher in the fresh fruits
than it was in
the commercially sold drinks. So, it would benefit the majority
of teenagers
who buy the commercially sold drinks (thinking they contain more
vitamin C
among other vitamins and minerals) to drink fresh fruit juices if they
want
the proper amount of vitamin C.
Bibliography
Endnotes 1) "Vitamin
C Content of a Lemon " The Chemicals of Life p.47
2) Bates, Chris
"Vitamin C, The Chameleon of the Vitamins" Biological
Science Review
November, 1991, p.11 3) Pitt, George "The Dark Side of
Vitamins"
Biological Science Review May, 1994, p.38 4) Bates, Chris
"Vitamin C, The
Chameleon of the Vitamins" Biological Science Review
November, 1991, p.12
5) http://www.cforyourself.com 6) http://www.cforyourself.com
& Bates,
Chris "Vitamin C, The Chameleon of the Vitamins"
Biological Science
Review November, 1991, p.12 7) http://www.cforyourself.com 8)
"Vitamin C
Content of a Lemon" The Chemicals of Life p.47 9)
http://www.cforyourself.com
Endnotes 1) "Vitamin C Content of a Lemon "
The Chemicals of Life p.47
2) Bates, Chris "Vitamin C, The Chameleon of
the Vitamins" Biological
Science Review November, 1991, p.11 3) Pitt,
George "The Dark Side of
Vitamins" Biological Science Review May, 1994,
p.38 4) Bates, Chris
"Vitamin C, The Chameleon of the Vitamins" Biological
Science Review
November, 1991, p.12 5) http://www.cforyourself.com 6)
http://www.cforyourself.com
& Bates, Chris "Vitamin C, The Chameleon of
the Vitamins"
Biological Science Review November, 1991, p.12 7)
http://www.cforyourself.com 8)
"Vitamin C Content of a Lemon" The Chemicals
of Life p.47 9)
http://www.cforyourself.com