The purpose of the experiment was to find out if the hydrogen ion concentration affects the colorants of foods in natural dyes, artificial dyes and fruit juice.

The procedures from my experiment began by making pH buffers with potassium phosphate.  The juices and dyes then had to be diluted with water.  The pH buffers then had to be separated into test tubes with 4ml in each.  1ml of each juice and dye were put in each test tube with buffer.  Mixed and swirled to even out solutions.  To begin measuring the color change you have to go through each test tube with each solution and pour them into the cuvette and put into the spectrophotometer.  The solution was then scanned.  The results were then calculated on the computer and then printed out.

The results of the experiment were that the juices and dyes did change colors when the hydrogen ion concentration changed.  The artificial dyes changed the least amount compared to the natural dyes and fruit juices.

In conclusion I found out that the artificial dyes are more stable, when the hydrogen ion concentration changes.  Although when testing for the colorants I found out that artificial dyes may be created by mixing two or more of them together, such as the blue and yellow dyes mixed created green.  Also I found out that not all of the dyes and juices became more red or blue with the change in the hydrogen ion concentration.

The purpose of this experiment was to find out if the hydrogen ion concentration affects the coloring of naturally made dyes, chemically made dyes, and fruit juices.

I became interested in this topic when I heard that when chemicals and ingredients were added to fruit and substances that the color may change because of the pH levels.  This caught my eye because I know when people buy items, they want them to look appealing, and if the pH changes the color and the scientists don’t understand why, they might not be able to sell their product.

I feel this project will help companies such as Tree Top, by when they are creating and producing mixtures for juices, etc. they will know how to change the pH or make sure it doesn’t change, so their foods and juices will look appealing for the consumer.

My hypothesis of this experiment was that when the dyes and juices were put into the pH buffers with higher acidity the dyes will become redder or they will become a darker red.  If the dyes are put in pH buffers with a lower acidity I feel they will turn to a deeper blue or green color.  I also feel that the artificially created dyes will change less in color than the natural made dyes.

The information I base my hypothesis, I found in a book called the Encyclopedia Britannica, Volume 4.  Which stated, “pH affects the aggregation of anthocynanin which is found in plants” and fruit.  The second part of my hypothesis is based on a discussion I had with Mr. Tom Eisele, who discussed that some of the artificial dyes have substances in them to stabilize the color so they will not change in mixtures.

The constants in the experiment were:
The amount of tested solution.
The amount of water used to dilute substance.
The equipment for the pH testing
The equipment to test for the wavelength of color.
Tested in the same location
Tested at the same time of day
Tested at the same temperature.
Procedures to create pH buffers
Procedures to create dye solutions.

The manipulated variable of this experiment was the level of pH the dyes and juices were tested in.

The responding variable was the color change found when the solution was put in the different levels of pH.

I measured the responding variable with a machine called a color spectrophotometer.  Which takes the solution and scans it with a light beam, and measures it in nanometers. The information is input into a computer and graphed and then the results are printed out.

1. Go to Tree Top.
2. Mix a two-liter batch of potassium phosphate solution, with two liters of water and 27.22 grams potassium phosphate.
3. Take 200ml of the potassium phosphate solution, and adjust the pH level by adding phosphoric acid and potassium hydroxide with an eyedropper.
4. Stick the pH gauge in the solution and measure on the scale to the correct pH you want.
5. Label ten plastic bottles with the pH level in them so you can identify the buffer.
6. For the buffer solution, distribute 200ml of mixture into plastic containers, with the correct level in each bottle.
7. Dilute dyes, juices, etc. with water so that the absorbance level of color is less than 1.0, you may not have to dilute some of the juices because they were diluted when they were made.
8. Put all buffers in to storage for the next day of testing.
9. Label all test tubes from pH 1.2, 2, 3, 4, 5, 6, 7, 8, 9,10 from left to right.
10. Put four ml of the pH buffer solution into each test tube that corresponds with its label.
11. Then add one ml of the diluted dye, or juice into each test tube.
12. Mix the tubes separately by shaking and swirling the solutions.
13.  Put sample into cuvette by pouring from the test tube.
14.  Put into the color spectrophotometer to be scanned.
15.  Scan the, sample test tube, which contains the sample and water to make sure the dilution is correct, which would be below 0.1.
16.  If not, redo sample.
17. If so, scan each test tube in the spectrophotometer separately, from 350 to 800 nanometers, or the visible wavelength, by:
18. Putting each test tube separately and pour part of the solution into a cuvette.
19. Then put the cuvette into the scanner and lock it in.
20. Hit the keys on the computer to calculate and graph results.
21. Repeat steps 7-19 for each dye and juice.
22. Calculate maximum absorbency for all dyes and juices.
23. Plot the function of the pH on to graphs with the nanometers.

Pre-Experiment Log
 

11/15/00	11:30AM-12:25PM	Research on the internet for a science project title.
11/16/00	11:25AM-12:20PM	Printed out science project packet instructions and reviewed  science projects.
11/17/00	11:30AM-12:30PM	Started looking for topics on the internet.
11/18/00	9:00AM-9:20PM	Called Mr. Eisele about topics and discussed ideas.
11/20/00	12:00PM-12:50PM	Talked to Mr. McMillen about project topics and ways to make old projects more involved.
11/21/00	11:25AM-12:25PM	Printed out and highlighted food topics and selected the best choices.
11/27/00	12:05PM-12:55PM	Talked to Mr. McMillen about favorite topics selections and where I could do the experiments for these topics.
11/28/00	11:30AM-12:25PM	Called and discussed topics with Mr. Eisele.
11/29/00	11:35AM-12:30PM	Started printing out information on all foods and nutrients.
11/30/00	11:25AM-12:20PM	Found topic on Anti-oxidants and printed out information.
12/1/00	8:00PM-8:20PM	Talked to Mr. Eisele, and found out that we didn’t have the technology to test for that around here, but I got an internet site I could research on for topics.
12/3/00	12:05PM-12:55PM	Looked on internet site that I got from Mr. Eisele and found some fruit and vegetables topics.
12/4/00	11:20AM-12:20PM	Researched on cooking vegetables and how space travel might affect the nutrients.
12/5/00	11:30AM-12:25PM	Highlighted information from the days before, and talked to Mr. McMillen about cooking vegetables, and the procedures I would have to take to do it.
12/8/00	11:25AM-12:20PM	Discussed topic with Mr. Eisele and found out some internet sites ands books I could look in to get information.
12/11/00	11:20AM-12:20PM	Started purpose and hypothesis.
12/12/00	12:00PM-12:45PM	Modified project so it would be different from my last years and improved and made more advanced.
12/13/00	11:30AM-12:25PM	Talked to Mr. Eisele about modifications and found out the project wouldn’t work.
12/14/00	11:25AM-12:25PM	Researched in the library and on the internet for a new topic.
12/15/00	11:30AM-12:20PM	Went to the public library to find books with project topics.
12/17/00	11:25AM-12:20PM	Went through books and researched on some of the new topics I found.
12/18/00	12:00PM-12:50PM	Talked to Mr. McMillen about the topics and discussed time management, where I could do it, and what I would have to find out before doing some of these projects.
12/19/00	11:20AM-12:20PM	Researched on the topics and found a few more back-up ideas.
12/28/00	9:30AM-10:00AM	Talked to Mr. Eisele about my new ideas and he gave me a few to think over and research on.
1/2/01	11:30AM-12:30PM	Found a topic on how pH affects the coloring of foods from Mr. Eisele.
1/3/01	11:25AM-12:20PM	Researched pH and printed out information from the internet.
1/4/01	11:20AM-12:20PM	Researched on the school library under pH and how it could affect food and drinks.
1/5/01	11:25AM-12:25PM	Research on hydrogen ion concentration, color, and how pH might affect the color of food, drinks, and materials.
1/8/01	12:00PM-12:50PM	Started writing purpose and researching for a hypothesis and something to base my hypothesis on.
1/9/01	11:30AM-12:25PM	Started writing my hypothesis and researched more on the internet on pH.
1/10/01	11:25AM-12:20PM	Started rough draft copy of my procedures, and talked to Mr. Eisele about when I was going to do the experiment.
1/11/01	11:30AM-12:25PM	Typed up the purpose, hypothesis, and procedures for Mr. McMillen.
1/12/01	11:20AM-12:15PM	Turned rough draft in and started writing out the experiment design and materials.
1/13/01	10:00AM-12:00PM	Got all papers and materials ready for the experiment at Tree Top.

Experiment Log  

In my research report you will be reading about the information gained from the research of the project “What is the Affect of the Hydrogen ion Concentration on the Colorants of Foods.”  You’ll be reading about pH and the affect it has on color.  The way a spectrophotometer measures the change in color and the measurement used to calculate the color change.  I will also explain how pH can affect the making of products and how the change in color can affect the marketing and presentation of foods.

 A measurement used to find out how acidic or basic a solution is, is called pH.  Another name for pH is potential of hydrogen and is calculated by how many hydronium and hydroxide ions there are in the solution.  The range or scale for pH is from 1-14.  If the solution is more acidic it will range from 1-7, if it is less acidic or basic it will range from 7-14.  Different ways to measure pH are with a pH meter or indicator, litmus paper that changes color or phenolphthalein.  When testing pH, you may create buffers to mix with different solutions to see how the pH affects the color of each solution.  In many ways the color can be affected by pH.  If more acidic, it is possible the solution will be redder in color, and if less acidic it could be more blue or green.

 Every substance has an amount of ions.  When the substances are put in water, they will produce either hydronium of hydroxide ions.  If hydronium ions were produces it was an acid, it would be considered a base if more hydroxide ions were produced.
 Acids can be very hazardous, but there are others that are essential to our lives.  Some acids are corrosive to skin and some that are poisons.  Then again there are some acids that our bodies consume everyday, such as lactic acid, citric acid, and acetic acid.  We also have hydrochloric acid in our stomachs and carbonic acid in our blood.  Some of the acids that are hazardous to people are sulfuric acid which can damage clothing and burn skin, nitric acid which is corrosive and dyes your skin, and hydrochloric acid which destroys skin and your lungs can be harmed by the fumes.  Acids usually react with metals and will taste sour.
 Bases or substances that have hydroxide ions are also common in life.  These are also very hazardous and used in many cleaners and soaps, because it can break down grease and oil, but it also is a corrosive substance.  Ammonia, calcium hydroxide and aluminum are also common bases.  You are able to identify a base by it feeling slippery to touch and it will taste bitter.

 A spectrophotometer is used to calculate the wavelength, by the absorption of a solute.  The amount that is absorbed indicates the color of the solute and the wavelength.  If the results show that the solute had a color it is telling us that the solute absorbs color and reflects the color that we see.  A spectrophotometer measures in nanometers, and is used by scanning a solution inside of a cuvette, which then transfers to the computer and calculates results.

 Pigments and light color have many similarities, but also many differences.  Light color depends a lot on the length of there waves, and pigments basically only depend on the dye or pigment colors.  “Pigment is a material that absorbs certain colors of light, and reflects other colors”.  The three primary colors for pigments are yellow, cyan, and magenta.  When these colors are all mixed together, they create a subtractive color, black.  When you mix the three primary colors you get every color and each color reflects and absorbs certain colors.  Magenta reflects blue and red and absorbs green.  Yellow reflects red and green and absorbs blue.  Cyan absorbs red and reflects green and blue.  The primary light colors are red, blue and green.  These colors are additive colors, because when you combine them all, it results in a white light.  All materials have color, and the color depends on the color of the light reflected.  An example of this is, when you see a grapefruit, your eye can see that it is a yellow-orange.  The skin of the grapefruit is absorbing the blue, which makes our eye stimulate to the color of yellow.  The wavelengths of light color can be short or long and that results in the change of color.  Short wavelengths are violet and the long wavelengths are red.  The colors the wavelengths result in are the colors of the rainbow, red, orange, yellow, green, blue, and violet.

 A color of a solution depends on the size and the distance waves are a part.  The color will range from red to a violet, from what our eye sees.  Waves that have long wavelengths are red and waves with short wavelengths are violet.  The colors waves go through are red, orange, yellow, green, blue, and violet. Visible light wavelengths usually range in between 0.000001 and 0.0000001.  Any corresponding point on the wave can measure waves wavelengths.  Some points measured from are the crest and trough.

The marketing and presentation of food is very important.  This benefits the companies who have to sell and produce products such as juice, dyes, etc. tremendously.  The color is an extreme part of this.  When you go into a store to buy a food, drink or material, you always buy the item that is the most eye-catching or the most appealing. So companies that produce and create the products to be sold have to make the best looking item to earn money.  pH is something that can affect the coloring and create problems.  A more acidic solution or an item with a lower pH can turn red and a solution or item with a higher pH or a more basic can turn blue or green.  Many substances when mixed with another will change pH and that can also result in a problem with color.  Which would most likely affect the selling of the product.  Away to keep this from happening, companies check the pH of the solutions and then combine them, and then again check the pH and add substances such as potassium hydroxide and phosphoric acid to make the pH the correct amount for the color you want the item to be.  Blue is a very popular color for dye, because it is a very stable color.  It is used in many products such as jeans and other clothing because when the pH changes from being in the wash or going through the process of making it, it is less likely to change.

Included in my research report I explained how color can be affected by pH and how that can hurt companies that have to present and market certain products that need to be eye catching and appealing to consumers.  I gave details on the process used to test for the change in color and the measurement used to identify the difference.  I also included information about the common acids and bases, and what they can do to the human body.

The original purpose of this experiment was to find out if the hydrogen ion concentration affects the coloring of naturally made dyes, chemically made dyes, and fruit juices.

The results of the experiment were that the color of the artificial dyes, natural dyes, and the juices did change in color.  The artificial dyes, changed the least amount, they just lightened in color.

The change in color of the solutions after being put in the hydrogen ion concentrations:
pH 10-1.2
Grape Juice-Blue, Purple, Pink, Red Pink
Prune Juice-Yellow Brown
Blackberry Juice-Purple, Light Purple, Pink, Pink Orange
Cranberry Juice-Purple, Pinky Purple, Pink Orange, Red Orange
Artificial Blue-Light Blue, Became lighter each change in level
Artificial Green-Dark Mint Green, Lighter each time, pale Yellow Green
Artificial Yellow-Medium Yellow, Became lighter each change in level
Artificial Red-Orange Pink, Became lighter each change in level
San Red-Dark Green, Blue, Purple, Pink, Dark Pink
Carmen Red-Dark Pink, Medium Pink, Light Pink
Cochineal Extract-Medium Orange, Light Orange, Dark Pink, Light Pink, Dark Red

Data

Results of The Affect of the Hydrogen Ion Concentration on the Colorants of Juices and Dyes

My hypothesis of the experiment was that when the dyes and juices were put into the pH buffers with higher acidity the dyes will become redder or they will become a darker red.  If the dyes are put in pH buffers with a lower acidity I feel they will turn to a more blue or green color.  I also feel that the naturally created dyes will change more in color than the artificial made dyes.

The results indicate that my first hypothesis should be rejected because when the dyes and juices were put in the different levels of pH they did not always turn red or blue according to the pH change as I hypothesized.  My second hypothesis should be accepted because the artificial dyes did not change in color as much as the natural dyes.  They lightened in color, but they did not change in direct color, for example from pink to purple to blue.

Because of the results of the experiment I wonder if you tested for the colorants of solid foods or if you created your own natural dyes with natural ingredients the results would be different.

If I were to conduct this experiment again, I would try to create my own dyes with natural ingredients.  I would also try getting juices and/or fruit that were organically grown, to see if the adding of chemicals and substances to non-organically grown fruit would be different from the organically grown.  Also if the substances and chemicals added could change the pH and possible affect the color.

Possible sources of error for this experiment were that different brands of juices could be created with different substances which could affect the pH, but it also could have had added color which the pH could work from or change to a completely different color.
 

Bates, R. G., Academic American Encyclopedia, 1995

Effect of Flower Coloration, Encyclopedia Britannica, 1768

Heimler, Charles H. and Price, Jack, Focus on Physical Science, Columbus, Ohio, Merrill Publishing Company, 1987

Tom Eisele, Quality Service Manager, Tree Top, January 15, 2001

Acids and Bases, http://www.encyclopedia.com/articles/00085.html, 12/16/00

Buffer, http://encarta.msn.com/index/conciseindex/5E/05E33000.htm?z=1&pg=2&br=1, 1/16/01

pH, http://www.mindquest.net/biology/shared/pH.html, 1/11/01

Potential of Hydrogen, http://www.powerup.com.au~tappin/pH.htm, 1/16/01

Uses of Food Colours & Lakes, http://www.neelikon.com/uses.htm, 1/31/01

Use of the Spectrophotometer, http://www.math.wsu.edu/gcb/courses/GenCB452/spec_use.html, 2/6/01

 I would like to thank many people for helping and influencing me on my science project.  I would like to thank the company of Tree top for allowing me to come into their lab and allowing  one of their workers to help me produce a project that suits the quality I desired. The main person I would like to thank is Mr. Tom Eisele.  This man allowed me to come into his lab and take time away from the projects he needed to work on and let me do my experiment.  He also took personal time and came down on a weekend to allow me to work around my schedule and still thoroughly complete everything in time.  This man taught me many things that I will be able to use in the future and that will hopefully benefit many people today.  My teacher Mr. McMillen influenced me tremendously and kept me going and didn’t allow me to quit or start an easier project.  He supported the ideas that I had and still gave me tips on how to improve my project.  The final two people I would like to thank are my mother and grandmother, Mrs. Berg and Mrs. Van Guse.  They took the time and effort to deliver me to the places I needed to be, to complete my project and experiment, and never let me stop before I had it done.  To all of you Thank You very much!!!

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