Please help me figure out my procedure!!!

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I have a science fair project about if different colored carrots contain different amounts of vitamin C. My procedure currently is to just clean and peel each carrot (purple, orange, and white), weigh and cut them to be equivalent (how many ounces should they be?), add ___ml of water and then blend them. I'm not sure if I have to separate the pulp of the carrot and the "juice" when measuring. I am planning to use Bartovation Ascorbic Acid Test Strips to measure the concentration of Vitamin C. Also, how do I calculate the concentration of vitamin c with the addition of __ ml of water? Please help!!! My science fair project is at stake!

[SciB]

Hi and welcome to SCibuddies.

Scientists often run into the same problems you have about how to do an experiment, and the way they solve them is by doing preliminary experiments to define the proper independent and dependent variables.

In your case, you want to measure and compare the amounts of ascorbic acid in various colors of carrot. My first question is what is your hypothesis? Are you saying that the common orange carrots have the most vit C? You could also ask the question of whether organic carrots have more vit C than carrots grown with chemical fertilizer. I think that would be an even more interesting and relevant question as organic produce always costs more and we wonder if it is worth paying extra for.

You could just cut a piece of each carrot about the same size and weigh it, but I think it would be more scientifically accurate if you weighed one whole carrot (minus the end pieces) and chopped it up in a blender using 1 mL of distilled water per gram of carrot. I don't know if this is the right amount of water, but it is a good place to start. A medium sized carrot weighs 2-3 oz (56 to 85 g), so you would blend the carrot in 56 to 85 mL of water depending on the weight. Strain out the pulp and use your test strips to measure the ascorbic acid content.

According to the carrot nutrition site: https://www.medicalnewstoday.com/articles/270191#diet
one medium carrot (61 g) has 3.6 mg of vit C. The site did not specify what color of carrot this was, but probably orange. The color comes from various plant pigments such as carotenes (orange) and anthocyanins (purple).

I don't know how sensitive your ascorbic acid test strips are but you could buy some ascorbic acid and make a standard curve to find out. Start with water as zero concentration and increase the vit C by some amount, reading the test strip each time and recording the corresponding value. That way you will know exactly how much vit C corresponds to a certain reading on your test strip.

If your carrot juice is too weak to test with the strips, try blending it in less water.

Try this and let me know how it comes out.

Good luck!

Scibee

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Thank you for your help! My hypothesis is: I believe that different colored carrots (orange, purple, and white) do contain different amounts of Vitamin C (ascorbic acid) because different colored carrots contain different nutrients, as well as different amounts of the same nutrients. Orange carrots mainly contain beta carotene while purple carrots mainly contain anthocyanins. Orange carrots also contain more beta-carotene than purple carrots. Therefore, I can hypothesize that different colored carrots contain different amounts of Vitamin C. After your suggestion however, I am thinking of changing it to whether organic carrots contain more Vitamin C than those grown with chemical fertilizer. I will make sure to update you on my experiment! Thank you again!

[SciB]

You are welcome! Glad to help.

I think the organic vs nonorganic experiment is more interesting and useful. You could still compare different colored carrots. Just because they have different pigments doesn't prove that they would have different vit C levels, but you have to do the experiment to find out.

Let me know when you have finalized your project direction and we can help you with perfecting the details and planning the statistical analysis.

Scibee

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What do I do if I can't purchase Vitamin C or Vitamin C tablets? Is this step necessary for my project? Also, does bottled water have any effect on my test? Or do I have to use a different type of water? *changed my topic to the one you recommended me, I also just tested two non-organic carrots that weighed 60 grams each and blended one of them with 60 grams of water and another with 45 grams of water. The test strips still showed up at 0.0%. I'm not sure what I'm doing wrong.

[SciB]

Hi,

You're not doing anything wrong. I think your test strips may not be sensitive enough to detect the relatively low levels of vit C in carrots. Test the strips on an orange or grapefruit, which have higher concentrations of vit C. Also check the manufacturer's description of the test. They should say what the lower level of detection is.

You don't have to make a standard curve using pure vit C, but it is useful like now when you are having a problem with the test strips. I'm sure you can order vit C powder online. I just did a search and there are many companies selling USP vit C powder.

The water you need to use is called distilled water and you can buy it in most supermarkets.

If your test strips are not sensitive enough, look online for a different brand that is more sensitive.

Let me know if you have more questions.

Good luck!

Sybee