What color of bell What color of bell peppers has the most peppers has the most

vitamin C?vitamin C?

An experiment by Hannah Ward

Abstract

The purpose for testing the hypothesis, “If red, yellow, and green peppers are tested for vitamin C content using the titration process, then the red pepper will have the most vitamin C because red peppers have a higher content of other vitamins and nutrients.” is to determine what color of pepper should be eaten if given the choice.

This hypothesis can be tested by using the starch titration process. To do this process, one would blend and strain a sample of pepper, then dilute it with water. Next, one would add a starch solution and one drop of iodine at a time until the sample turns a blue-black color. This happens because the iodine absorbs the vitamin C first, and then reacts with the starch solution, turning it the blue-black color. The pepper that takes the most drops to absorb all the vitamin C will have the most of the vitamin in it.

All of the red peppers (except one) took longer to turn black than the green and yellow peppers. Research also shows that red peppers have more of other vitamins and nutrients than yellow and green peppers. Due to these results one must conclude that red peppers have more vitamin C in them than green or yellow peppers. This knowledge can be applied to real life when grocery shopping or planning menus or even in dieting. This experiment could be extended even further by adding orange peppers into the experiment.

Purpose and Problem• Purpose: The purpose in

doing this science project is to learn what maturity of the pepper contains the most vitamin C. It is important to this, especially for people with health problems who are in need of vitamin C. This is also a helpful thing to know if someone has a pepper plant in their garden, and they want to know the right time to pick the peppers for the most nutritional value. Vitamin C is necessary for the body, so knowing which maturity of bell peppers has the most vitamin C, will help one receive the most amount of vitamin C.

• Problem: How does the maturity of a bell pepper affect the content of vitamin C in it?

http://www.kraftfoods.com

Hypothesis

If the red, yellow, and green peppers are tested for vitamin C content using the titration process, then the red pepper will have the most vitamin C because the red peppers have a higher content of other vitamins and nutrients.

Materials

• Iodine Solution• Starch Indicator Solution• 5 beakers or measuring containers• Blender • Scale• 10 g samples of green, yellow and red bell

peppers (5 for each color)• Distilled water• Strainer

VARIABLES

• INDEPENDENT: color/maturity of the pepper

• DEPENDENT: vitamin C content

• CONSTANTS: amount of starch, amount of iodine solution, size of pepper sample

Set-Up

• CONTROL GROUP: The green pepper samples

• EXPERIMENTAL GROUP: The red and yellow pepper samples

Procedures• Put the 10 g sample of a green pepper in a blender with

100 mg of distilled water and blend until smooth.• Strain pulp with strainer and pour into a volumetric flask.

Pour out all but 25 mg of sample then add distilled water until sample is up to 75 mg.

• Repeat steps 1 and 2 with the red and yellow samples.• Add 1 mL of starch indicator solution.• Add one drop of iodine at a time to each sample until the

sample is a blue-black color.• The first sample to have a blue-black color to it will have

the least vitamin C, and the last one will have the most.• Repeat steps 1-6

Data

Trial # Red Yellow Green

1 7 6 4

2 5 8 5

3 9 3 5

4 8 6 4

5 6 6 9

Amount of Iodine until Titration Ended (drops)

Red Yellow Green

Mean 7 5.8 5.4

Median 7 6 5

Mode None 6 4 & 5

Range 4 5 5

Mean, Median, Mode, and Range

Graphs

Vitamin C Content in Bell Peppers

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1 2 3 4 5

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Average Vitamin C Content

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Red Yellow Green

Color of Peppers

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Series1

Interpretation of Data

The data resulting from this experiment supports the given hypothesis. The red pepper samples took the most iodine to end the titration process, so therefore, red had the most vitamin C. Yellow had the next most vitamin C, and the green the least amount of it. The difference between the data of the red, yellow, and green peppers was significant and for the most part, clearly defined.

There were some outlier samples in my experiment. They were the green sample from trial # 5 and the yellow from trial # 3. The green sample had a lot more vitamin C in it than the other samples, and the yellow one had very little compared to the other samples. This may have been because the measurements of added distilled water were slightly off.

Some trends in the data was that the difference in the levels of vitamin C in the green and yellow peppers was usually very slight, while there was quite a difference in the levels of vitamin C in the red and yellow peppers.

ConclusionThe hypothesis that the red pepper would

contain more vitamin C than the green and yellow peppers was proven to be correct by the collected data. Only once did the red samples not have the most amount of vitamin C in them. The red probably has the most vitamin C in it because it spent more time on the pepper plant than the yellow and green peppers, and therefore had more opportunity and time to take in vitamin C.

Ways that the experimental design could be improved are adding more starch solution to the samples so the end of titration could be seen more clearly. Also adding more distilled water would have helped define the end of titration better. It would also be better to have more exact measurement of iodine than a drop.

Ways that the experimental design could be improved are adding more starch solution to the samples so the end of titration could be seen more clearly. Also adding more distilled water would have helped define the end of titration better. It would also be better to have more exact measurement of iodine than a drop.

Future StudyThere would be many ways to expand this

experiment and find more about which pepper would be the healthiest. For example, one could add an orange pepper into the experiment. Someone could also see if the age of the pepper affects the vitamin C content in it, or other factors change the results. A study could also be conducted to see if other vitamins and nutrients were more abundant in the red peppers, rather than the green or yellow peppers. It would be very useful to expand this experiment, and could improve many people’s health if it were done.

Acknowledgements

Thank you to my parents for being very supportive and buying everything I needed, and to Mrs. Backs for guiding me through the experiment

Bibliography

• Collins, Anne. "Green Peppers - Diet Nutrition." Weight Loss Diet Program, FREE Diet Advice! Weight Loss Diets, Low Carb Plan. N.p., n.d. Web. 19 Nov. 2009. <http://www.annecollins.com/diet_foods/peppers-green.htm>.

• Ehrlich, Steven. "Vitamin C (Ascorbic acid)." University of Maryland Medical Center. N.p., n.d. Web. 19 Nov. 2009. <http://www.umm.edu/altmed/articles/vitamin-c-000339.htm#>.

• Henderson, Nellie. "University of Maine Cooperative Extension homepage." University of Maine Cooperative Extension homepage. N.p., n.d. Web. 19 Nov. 2009. <http://extension.umaine.edu>.

• "International Union of Pure and Applied Chemistry." [IUPAC]IUPAC.org . N.p., n.d. Web. 19 Nov. 2009. <http://www.iupac.org/goldbook>.

• W., Charles, and Ph. D. Marshall. Vitamins and Minerals: Help or Harm?. Yonkers: Consumers Union, 1985. Print.

AppendixTitration: The process of determining the quantity of a substance A

by addingmeasured increments of substance B, with which it reacts (almost alwaysas a standardized solution called the titrant, but also by electrolytic generation,as in coulometric titration) with provision for some means of recognizing(indicating) the endpoint at which essentially all of A has reacted.If the endpoint coincides with the addition of the exact chemical equivalence,it is called the equivalence point or stoichiometric or theoreticalendpoint, thus allowing the amount of A to be found from known amountsof B added up to this point, the reacting weight ratio of A to B being knownfrom stoichiometry or otherwise (IUPAC, 1).