THE ABILITY OF SALT, NAHCO3 AND VINEGAR FOR WASHING BLEACHING AGENT IN BEAN SPROUT

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Members

1 •Ravipa Vongrojrattana•M.4/1 No.7

2 •Phuchit Santasawang•M.4/1 No.20

3 •Techin Tungcharernpaisarn•M.4/1 No.15

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Advisor

Dr. Usa Jeenjenkit

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Introduction

Have you ever eaten bean sprout ?

I am sure you have ever eaten it.Because it is in many Thai dishes

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But do you know that there are foxy merchant use bleaching agent in bean sprout.

Na2S2O4

Sodium HydrosulfiteSodium Dithionite

And this chemical substance is toxic.

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It made us thought that can we wash bleaching agent in bean sprout ?

but what we will use. Then we thought what our moms

always use to wash vegetable . It is NaCl Vinegar and NaHCO3

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Our inquiry

question

Can The solution of Nacl , Vinegar and NaHCO3 wash bleaching agent in bean sprout better than pure water ?

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Material & Methods

For the experiment, we prepared 3 solution of

Vinegar, NaHCO3 and salt with 3 different concentration

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First ,we used vinegar 2% , 3% and 5% V/V by using 500 cm3 of volumetric flask

: added Acetic acid (CH3COOH) 10, 15 and 25 cm3

into each flask ,filled in water until the volume of solution was 500 cm3, mixed them together

example of vinegar solution

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Then we used NaHCO3 3%, 4% and 5% M/V by using 500 cm3 of volumetric flask

: added NaHCO3 15, 20 and 25 g into each flask ,filled in water until the

volume of solution was 500 cm3, mixed them together

NaHCO3

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Next, we used salt 3%, 4% and 5% M/V by using 500 cm3 of volumetric flask

: added salt 15, 20 and 25 g into each flask ,filled in water until the

volume of solution was 500 cm3, mixed them together

example of salt (NaCl) solution

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For chemical detection we use KMnO4 solution to test quantity of bleaching agent in bean sprouts : dissolve 2 flakes of KMnO4 in 1 liter of water (=0.0677g/l)

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put 30 g of bean sprout in the 10 beakers of solution (including water).

Vinegar 2%

Vinegar 3%

Vinegar 5%

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NaHCO3 3% NaHCO3 4% NaHCO3 5%

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NaCl 3% NaCl 4%

NaCl 5%

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water

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waiting for 20 minutes

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Added KMnO4 solution 10 cm3 into the test tube mixed well and waited for 5 minutes

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then put away the bean sprout and put 10 cm3 of solution from each beaker into the test tube.

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Test the changing of the color by using spectrophotometer.

Note : use 400 nm

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Result  Vinegar ability for washing

bleaching agent in bean sprout charts

KMnO4 + water Vinegar0

0.1

0.2

0.3

0.4

0.5

0.6

2%

3%

5%

without Bean sprout

with Bean sprout

Abs

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 Vinegar ability for washing bleaching agent in bean sprout

2%

3%

5%without Bean

sproutwith Bean sprout

KMnO4 + water 0.501 0.095

Vinegar0.019

0.08

0.02

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NaCl ability for washing bleaching agent in bean sprout charts

KMnO4 + Water NaCl0

0.1

0.2

0.3

0.4

0.5

0.6

3%4%5%without beansproutwith bean sprout

Abs

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Salt ability for washing bleaching agent in bean sprout

3% 4% 5%

without beansprout

with bean sprout

KMnO4 + Water 0.501 0.095

NaCl 0.205 0.196 0.308

3%

4% 5%

without Bean sprout

with Bean sprout

KMnO4 + water 0.501

0.095

Salt0.205

0.196

0.095

NaHCO3 ability for washing bleaching agent in bean sprout charts

KMnO4 + Water NaHCO30

0.1

0.2

0.3

0.4

0.5

0.6

3%4%5%without bean sproutwith bean sprout

Abs

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NaHCO3 ability for washing bleaching agent in bean sprout

3% 4%

5%

without Bean sprout

with Bean sprout

KMnO4 + water 0.501 0.095

NaHCO3

0.19

20.186

0.361

Discussion

From this experiment , We can see that Na2S2O4 can dissolve the best in vinegar solution because vinegar solution can decompose Na2S2O4 .(Mayer ,1992 )

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We can assume that the NaCl solution and NaHCO3 solution dissolve Na2S2O4 worse than vinegar solution because they have Na+ ion that dissolve in water already and it disturb the dissolving of Na2S2O4

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For this result ,it’s oppose with Aubrey result because he said that all of vinegar, NaHCO3 and salt are good to wash the vegetable and decompose toxic .

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Future research

This project will help your health by washing the bleaching agent from the bean sprout .If you want to continue this project , you can use other chemical substances to wash bleaching agent from bean sprout .

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Suggestion

if we have more time, we should do the experiment again for 2-3 times to make sure that we have accurate result.

Maybe we use more kinds of solution to make us know what the best cleaner solution other than we used.

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References Aubrey.(2011). Vegetable Washing Tips. Retrieved August 7,2011, from

http://www.ehow.com /info_8635506_home-cleaning-sprays-made- bleach.html. Dvorak, G. (2005 ,February). Disinfection. Center for Food Security and Public

Health. Ames, IA: Center for Food Security and Public Health, Iowa State University. p. 12. Retrieved August 7,2011, from http://www.cfsph.iastate.edu /BRM/ resources/Disinfectants/Disinfection101Feb2005.pdf.

KFDA.(2009). Find sodium hydrosulfite at GFS Chemicals. Retrieved August 16,2011,

from http://www.chemindustry.com/chemicals/0523798.html. Weinrach, J. B.; Meyer, D. R.; Guy, J. T.; Michalski, P. E.; Carter, K. L.; Grubisha, D.

S.; Bennett, D. W. (1992). A structural study of sodium dithionite and its ephemeral dihydrate. Retrieved August 16,2011, from http://en.wiki

pedia.org/wiki/Sodium_dithionite. Wiebold,D.(2007). Brief Introduction of Mung Bean. Retrieved August 8,2011, from http://en.wikipedia.org/wiki/Mung bean.

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QUESTION&

ANSWER34