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Streszczenie

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									Chemistry project – Netherlands:                    acidity is caused by one edinol group OH (not
                                                    by carbolic group). Actually, dehydroascorbic
        All vegetables consist of plant cells.      acid does not have acidity character.
Walls of these cells let in many substances         Hemicellulose is polysaccharide. Thanks to
like water and breathing-gases. However,            its shape and structure it undergoes hydrolyze
both salt and starch are not able to get            without any problems by diluted acid or basic
through this barrier. Stiff walls contain           solutions. Pectin plays a very important part
hemicelluloses frame. During boiling these          in ripening of vegetables. During this process
structures undergo thinning. This process           as well as boiling process pectin undergoes
makes cells thinner so much that ions are           disintegration, which makes walls softer.
automatically rinsed from cells. There is a         Both substances perfectly dissolve in water.
hypothesis saying that it mainly depends on                 It leads to changes in structures of
the temperature. To check authenticities of         walls and enables rinse of salt and ascorbic
this theory, 4 samples of bean were being           acid, which is present in vacuoles of plant
heated for 5 minutes in temperature of 60, 70,      cells.
80,95oC in solution of table salt in
concentration of 1 mol/liter. Higher                Therefore the research question is:
temperature caused rise in concentration of          What influences color of green vegetables
released ascorbic acid creating acid                               during boiling?
conditions enabling ion replacements.
                                                    Our hypothesis says that water has got its
                                                    color from substances from bean under
Introduction                                        influence of boiling (vitamin C – responsible
                                                    for yellow color) and derivative compound of
        Vegetables are plants. Each one of          rinsed from ions of Mg and chlorophyll
them has a schematic construction. The cell         (responsible for green color).
consists of many elements, e.g. Ascorbic acid
popularly called vitamin C. This acid for the
first time was separated in crystalline state       Experiment procedure : 1 approach
from cortex of adrenal gland and later
received from pepper. Ascorbic acid is                      Sample of bean from each boiling
colorless crystals dextrorotatory sensitive to      looked different. They were different not only
heating and oxidation, what destroys its            in shade of green but also in structure. The
physiological inference. Ascorbic acid is hard      most green was dipped in water solution of
impediment factor (titrating by iodine              table salt for 5 minutes in room temperature.
immediately uses 2 atoms of iodine making           The least green (simultaneously consisting of
iodoform). Formed product of oxidation is           most dark dye) was they one boiled in the
dehydroascorbic acid. As a result of reduction      NaCl solution in temperature of 100 C. The
it again converts into ascorbic acid.               intensification of green decreased in
                                                    proportion to increasing temperature.



                                                            6

                                                            5

                                                            4
                                                    GREEN




                                                            3

                                                            2

                                                            1
         ASCORBIC ACID        DEHYDROSCORBIC ACID
                                                            0
                                                                1      2                 3           4
      Ascorbic acid is the acid of strength                                TEMPERATURE
carboxylic acids, can be titrated by hydroxide,
decomposes carbonates and creates salts. Its
  However, the bean boiled in the solution in       Data Analysis
  the temperature 100oC with NaHCO3 had the
  color similar to the bean kept in room                   Amount of rinsed salt during boiling
  temperature                                       in every test tube, was boosted. Support of
                                                    this theory is: “increased use of AgNO3
                                                    during titration”.
  Results

  Only bean kept in room temperature in NaCl        Color – reason od decrease:
  solution didn’t not change color in relation to
  the basic bean with NaHCO3.                               With rise of temperature Mg2+ ions
  In titration of salt solution, not boiled, we     were released faster and faster because
  used 19,7ml AgNO3. Feel’s group used 21, 16       progressing dissolution of cell membrane
  ml AgNO3, which sure is result of SURPLUS         frame, build from Hemicellulose, which
  of salt in water solution, because their          enables getting out Mg2+. An additional factor
  solution had 3g salt too much.                    enabling replacing Mg2+ for 2H+ ions was
                                                    acidity circle reaction, made by forced out
                                                    vitamin C contained in plants. Dose of bean
  Color:                                            boiled in NaCl and NaHCO3 solutions in
                                                    100oC didn’t change own color in comparison
         For room temperatures were used 19,        to bean held in room temperature in NaCl
  7 ml AgNO3- bean color did not change. For        solution. However, color of solution became
  solution in 60oC 19,4ml of reagent were used      yellow-green. We can suppose that NaHCO3
  and intensity of green color went down by         is stopping flowing out Mg2+ ions from bean
  one tone. For solution in temp 70oC were          because of neutralization of reaction circles.
  used 19,6ml AgNO3 and green tone went             Substances deing water solutions are
  down again. Titrationing solution 80 oC we        probably from derivatives ascorbic acid and
  used 21.3 ml, for 95 oC - 22, 2 ml. Green         other organic substances
  color was changing to dark brown color. For
  100 oC we used 24ml AgNO3, bean got
  brazen. A sample of bean boiled in 100 o C        Discussion I:
  with NaHCO3 looked like the bean kept in
  room temperature.                                         Results of titrations of basic solution
                                                    and obtained results show that amount of
                                                    NaCl in all solutions rose up in comparison to
                30                                  basic solution. These results certainly confirm
                25                                  a hypothesis: all plant cells green bean or
USED OF AgNO3




                20
                                                    generally plants, rinse out Na+ and Cl- ions
                                                    during heating in NaCl solutions containing
                15
                                                    salt used for cooking. We can suppose that
                10                                  ions Na+ and Cl- were rinsed out from
                5                                   vegetable cells during cooking. Both our and
                                                    Fels research had similar results, what
                0
                                                    confirms hypothesis that NaCl in solution has
                     0   50       100       150
                                                    an effect on rinsing out Na+ and Cl- ions from
                         TEMPERATURE
                                                    bean. It is caused by a drive to make NaCl
                                                    concentration on the same level in bean and
  Assumption:                                       in water solutions (it is diffusion rule). To
                                                    confirm this, we conducted an experiment.
         Color of bean depends on amount of         We were boiling beans in saturated solutions
  vitamin C, because the bigger its                 (1750g NaCl/ 5L H2O in 100oC) Compared
  concentration, the more Mg will be rinsed         results if the main solution titration with
  out (acid circle) and what we get is brown        results of the water titration from 4 different
  bean.                                             portions show that salt from high
                                                    concentration area(water) was absorbed to
lower salt concentration area (bean), to make
the same concentration level in water and
bean.
As a result of boiling, ascorbic acid is always
rinsed out and makes acid environment,
where ions Mg2+ are rinsed out, because
replacing ions Mg2+ to two ions H+ happens
only in this environment. Vitamin C in high
temperature in oxygenic conditions is
changed into acid soluble in H2O. Thanks to
solubility in H2O acid is dissociating to ions
H+ and the acid resist. These ions H+ replace
Mg2+ ions, so Mg2+ ions are rinsed out, and
this process leads up to change color. One
sample boiled with NaHCO3, did dot change
color because H+ ions did not replace Mg2+
ions on account of change of environment
from acid (made by vitamin C) to alkaline
(made by add NaHCO3). The result is
dehydroascorbic and easy-soluble in water
H2CO3 (acid, which brake up for H2O and
rushing out CO2). H+ ions which forced out
Mg2+ ions, were absorbed by acid rest
(HCO3-), making carbon acid, which is not
durable in water environment. Color change
can be made by chlorine compounds, but it
needs further research.

								
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