Sodium hydrogen carbonate and Vitamine C Vitamine A

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					              Sodium hydrogen carbonate and Vitamine C
               Zeevenhooven, L., Cuvelier, F. & Bosman, M.
     Gymnasium Felisenum Velsen-Zuid, Vrije Universiteit Amsterdam, The

Vegetables contain Vitamin C. Vitamin C is important for people’s health. Vitamin C is
stored in plant cells which are verry stiff, when heated, the cells will become permeable and
weak so the vitamin C can leak out of the grociourie. Sodiumhydrogencarbonate affects the
amount of vitamin C that has leached out of the plant cell. The hypotheses is that this process
is dependent on the concentration sodium hydrogen carbonate. To test this hypothesis 5
portions of brocoli were heated and than boiled for 5 minutes in different concentrations
sodiumhydrogencarbonate. The regained solutions we titrated with DCPIP, with a little math
we could calculate how much vitamin C leached out. It seemed that the higher the
concentration sodiumhydrogencarbonate was the more vitamin C leached out.

Down in the dutch golden century, when             ring system with an Mg2+ ion in its centre.
people got sick at a ship after a long time        When cooking with normal water there
at sea, it was because of a lack of vitamin        occurs an substitution of the Mg2+ by two
C. Vitamine C is in first place important          H+ ions. This gives a compound called
for a good body resistance. Besides that it        phenophytin, which is olive green/brown
takes care of healthy bones, teeth and a           and causes for the colour of overcooked
good blood circulation.                            vegetables. In acidic conditions the
                                                   substitution of Mg2+ by two H+ ions goes
                                                   by smoothly. Sodium Hydrogen keeps the
                                                   conditions alkaline and that will minimize
                                                   the replacement of the Mg2+ ion and result
                                                   in less conversion of chlorophyll to
                                                   phenophytin, along with a more enticing
Figure 1: molecular structure of vitamin C         appearance to the vegetables. Sodium
                                                   hydrogencarbonate,     NaHCO3,      is    a
Furthermore vitamin C is an antioxidant            melecule of a strong base (sodium
and it protects the body in coorporation           hydroxide) and a weak acid (carbonic
with vitamin E against the free radicals.          acid).
Free radicals play a part in the processes
that make you older. Vitamin C also
stimulates the adoption of irons. Vitamin C
is sensitive for temperature and
sodiumhydrogencarbonate. When heated
very long the ammount of vitamin C will            Figure 2: molecular structure of carbonic acid
be decreased. When heated at a constant
temperature with a different concentration         The ammount of leaked out vitamine C can
of sodium hydrogen carbonate more                  be calculated after the residu is being
vitamine C will be lost. The colour of             titrated with DCPIP. This is because the
green vegetables is largely due to                 reaction that occurs is a redox reaction.
chlorophyll. Chlorophyll has a porphyrin           DCPIP is a strong oxidator. When it reacts
as an oxidator the following reaction takes           Experimental procedure and approach
place.                                                Broccoli was used to make five portions of
                                                      20 g with approximately the same grade of
                                                      partition. This portions were cooked in
                                                      solutions of NaHCO3 with different
                                                      concentrations and in a stock solution with
                                                      only distilled and deionised water. 0,1; 0,2;
 DCPIP                                                0,3; 0,4 ; mol/L solution was made by
 Oxidised form                  Reduced form          weighing out the right amount by
Figure 3: reaction of DCPIP as an oxidator            considering that the solution shall be
                                                      diluted by 200 ml distilled water. Five
Pectin is a structural polysaccharide, which
                                                      conical flasks were filled with the different
is present in primary cell walls of plants.
                                                      solution plus the broccoli. Each conical
Pectin causes that the cell walls of a plant
                                                      flask was cooked for 5 minutes. The five
become softer during the ripening process.
                                                      ‘cooking’ waters were then filtered into
The same process takes places during
                                                      beakers. Of each water there was taken
cooking, pectins become soluble and are
                                                      three times 10 ml by using a pipette and
extracted into the cooking water making
                                                      hydrochloric acid was added to the fifteen
the vegetable go mushy. So the wall
                                                      solutions untill the pH was beneath four.
structure of the cells changes and this gives
                                                      Otherwise the titrations with DCPIP don’t
the opportunity to salts and vitamin C to
                                                      work. We use DCPIP because it reacts
escape. The pectin molecule contains –
                                                      with vitmine C. It functions as an indicator
COOH        groups      that   react     with
                                                      from wich we can calculate later on how
                                                      much vitamin C has leached out. By using
NaHCO3(aq)         +      R-COOH(s)        
                                                      a burette with DCPIP for the titrations
NaCO3(aq)+ H2O(l) + R-CO-(aq)
Equation     1:     pectin        reacts       with   three results came out for the different
sodiumhydrogencarbonate                               concentrations NaHCO3. The averages
                                                      were used to calculate the ammount of
Were doing this research because we find              mole of vitamin C. This results were
it interesting to know more about the food            plotted versus the concentration of the
we eat and how healthy the food is.                   NaHCO3 and compared with the ammount
The research question is: What amount of              of mole of vitamin C in the stock solution.
vitamin C is leached out of the plant cells
when heated at the same temperature in                Results
different concentrations of sodium                    For all titrations we took three times 10mL
hydrogen       carbonate?   Thus       which          from each of the different concentrations.
concentration of sodiumhydrogencarbonate              The titrations were with DCPIP and for
is most healthy to cook in?                           each concentration we worked out an
Our hypothesis is that the leaching out of            avarage of the added ml of DCPIP. Table 1
the vitamin C depends on the concentration            shows the avarage of 0M after three
sodiumhydrogencarbonate and the higher                different titrations.
the concentration the more vitamin C will             0M             solution DCPIP       solution
be leached out. Because vitamine C reacts             10,0mL                  added (mL)
with sodiumhydrogencarbonate and if we                               10,00       2,38
add      more      sodiumhydrogencarbonate                           10,00       2,30
vitamin C has a bigger possibility to react.                         10,00       2,34
                                                      Avarage 10,00ml            2,34
                                                      Table 1 : added DCPIP solution (mL)
                                                      In all the 4 heated beakers the solutions
                                                      turned from a clear solution to a trebly
brown solution. The higher the
concentration sodium hydrogen carbonate,      Concentration           Average of added
the browner the solutions became. After       sodiumhydrogen-         DCPIP(mL)
the titrations with DCPIP the solutions       carbonate (M)
turned pink/ red. Table 2 shows the           0                       2,34
obtained averaged ammounts of mL              0,10                    1,33
DCPIP added to the recovered solutions        0,20                    1,73
(0M-0,4)                                      0,30                    1,93
                                              0,40                    2,52
                                              Table 2: avaraged mL of the added DCPIP for
                                              each of the concentrations

Data analysis
Because of the fact that we used              176,13 u. The results of these calculations
9,14·10-4M DCPIP we could calculate           are shown in table 4.
how much mol DCPIP we added. Because
DCPIP and vitamin C react in mol relation     Moles vitamin C         Leaked         out
1:1 we also know how much vitamin C                                   ammount         of
came free during the cooking proces. So to                            vitamin C (gr)
calculate this we take 9,14·10-4M wich we     0,00214·10-3            3,769·10-4
multiply with the obtained mL of DCPIP.       0,00122·10-3            2,149·10-4
The results of the calculation are shown in   0,00158·10-3            2,783·10-4
table 3 and.                                  0,00176·10-3            3,100·10-4
                                              0,00230·10-3            4,051·10-4
Concentration         Moles        DCPIP       Tabel 4: calculated worths of vitamin C that is
sodiumhydrogen-       added to the 10         leaked out of brocoli in grams
carbonate (M)         mL solutions
0                     0,00214·10-3            Discussion
0,10                  0,00122·10-3            The results in tabel 4 show that our
0,20                  0,00158·10-3            hypothesis was right, the higher the
0,30                  0,00176·10-3            concentration sodium hydrogen carbonate
                                              the more grams vitamin C will leak out of
0,40                  0,00230·10-3
Table 3: obtained moles DCPIP, and so the
                                              the cell. So the healthyest concentration is
obtained moles vitamin C                      the lowest concentration because more
                                              vitamin C wil stay in the brocoli that you
Now that we know the ammount of moles         are going to eat, but not 0M because that
of vitamin C came free in the solutions we    has more vitamine C leached out. This is
can calculate how much grams of vitamin       because demiwater also weakens the
C came free. Therefore you must multiply      plantcells so vitamine C could easily
the ammount of moles of vitamin C with        escape.
the molleculair weight of vitamin C wich is   Our coorporation was very good during the
                                              investigation we didn’t had any problems
                                              at all. We had a slight problem when we
                                              used the wrong concentration of acid. For
                                              the rest everything went as planned and we
                                              found        it       fun       to       do.

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