Need help urgently with science project! Orange J Experiment

[streetsidedown313]

All right. So my project is about how if putting orange juice in refrigiration, freezing it, microwaving, boiling, and leaving it in the room (my control, I think?) affects the vitamin c level of the orange juice. So far I have done the experiment and what I did was I had the orange juices (after they were in the enviorments) and took droplets of each one (seperately) to see how many droplets it would take to dissolve a Vitamin C indicator made of Corn Starch and iodine. [b]What I need to is if it is the more amount of drops it takes to dissolve the indicator, the more vitamin c (or vice versa) and why[/b]. I've researched everywhere, but haven't found anything. HELP!!!!!!! THANKS!!!!

[Louise]

All right. So my project is about how if putting orange juice in refrigiration, freezing it, microwaving, boiling, and leaving it in the room (my control, I think?) affects the vitamin c level of the orange juice. So far I have done the experiment and what I did was I had the orange juices (after they were in the enviorments) and took droplets of each one (seperately) to see how many droplets it would take to dissolve a Vitamin C indicator made of Corn Starch and iodine. What I need to is if it is the more amount of drops it takes to dissolve the indicator, the more vitamin c (or vice versa) and why. I've researched everywhere, but haven't found anything. HELP!!!!!!! THANKS!!!!

I think all your questions have been answered here before. Look at this thread and the links the expert provides.

https://www.sciencebuddies.org/mentorin ... sc&start=0

and here

https://www.sciencebuddies.org/mentorin ... ht=vitamin


Hope these two links help. Post back if you have more questions.
Louise

[staryl13]

All right. So my project is about how if putting orange juice in refrigiration, freezing it, microwaving, boiling, and leaving it in the room (my control, I think?) affects the vitamin c level of the orange juice. So far I have done the experiment and what I did was I had the orange juices (after they were in the enviorments) and took droplets of each one (seperately) to see how many droplets it would take to dissolve a Vitamin C indicator made of Corn Starch and iodine. What I need to is if it is the more amount of drops it takes to dissolve the indicator, the more vitamin c (or vice versa) and why. I've researched everywhere, but haven't found anything. HELP!!!!!!! THANKS!!!!

Hi!
This seems like an interesting idea. I don't think your indicator is accurate enough to tell exactly how much vitamin C is present in the orange juice, it will simply allow you to make relative comparisons between the amounts of vitamin C in different samples. This website might be helpful since it explains the use of the indicator in different samples of orange juice.
http://www.accessexcellence.org/AE/ATG/ ... index.html
Hope it helps, good luck!

[streetsidedown313]

thanks!! I know it really isn't that acurate. However, comparisions are okay for my project right now, I think. I'm still a little confused on whether I should say for my conclusion though, that (as to results not necessarily in real life with accuracy) frozen orange juice had more vitamin c after the project was done or stored in a room oj, since it took seven drops of room stored oj to dissolve the indicator and 15 drops of tbe frozen

[staryl13]

thanks!! I know it really isn't that acurate. However, comparisions are okay for my project right now, I think. I'm still a little confused on whether I should say for my conclusion though, that (as to results not necessarily in real life with accuracy) frozen orange juice had more vitamin c after the project was done or stored in a room oj, since it took seven drops of room stored oj to dissolve the indicator and 15 drops of tbe frozen

Hi again!
Great, it sounds like your project is coming along. I would assume that the room stored oj has more vitamin c since it only took 7 drops, but it really depends on the average amount of drops based on how many trials you did. The more trials, of course the more accurate. If you're confident that you have pretty accurate data, I would go ahead and state your conclusion but add in that based on the nature of the indicator, it is not possible to test the hypothesis 100% accurately. good luck!

[streetsidedown313]

Thanks again!!!! You have been a big help. I just have one more question (so far...there may be more): Does anyone know the affect of freezing in the freezer on vitamin C. I don't know how far it varies from refrigeration, so I suppose you could call it extreme refrigeration, but I am at the point where I am writing why the frozen orange juice had the least amount of vitamin C in it, oh and okay, ANOTHER question (I tend to have a lot of them), would I have a control in this experiment? I think it would room stored orange juice, but I am not sure...

[staryl13]

Thanks again!!!! You have been a big help. I just have one more question (so far...there may be more): Does anyone know the affect of freezing in the freezer on vitamin C. I don't know how far it varies from refrigeration, so I suppose you could call it extreme refrigeration, but I am at the point where I am writing why the frozen orange juice had the least amount of vitamin C in it, oh and okay, ANOTHER question (I tend to have a lot of them), would I have a control in this experiment? I think it would room stored orange juice, but I am not sure...

Hi!
I would assume that oj in the freezer would probably have less vitamin c but it might be cool to test it out for yourself just to make sure. Depending on your other types of oj, I would use room stored orange juice as a control. It also depends on the hypothesis, so if you're attempting to test whether refrigeration has any effect on vitamin c, then the room stored oj would be a control. Your project seems to be going well, post back if you have any more questions..

[Louise]

thanks!! I know it really isn't that acurate. However, comparisions are okay for my project right now, I think. I'm still a little confused on whether I should say for my conclusion though, that (as to results not necessarily in real life with accuracy) frozen orange juice had more vitamin c after the project was done or stored in a room oj, since it took seven drops of room stored oj to dissolve the indicator and 15 drops of tbe frozen

You aren't "dissolving" the indicator. The chemistry is explained in both the links I provided. Here is a specific link:
http://paws.wcu.edu/bacon/Vitamin%20C.pdf

If you had a very accurate dropper and some solutions of known concentration, you could get a fairly accurate determination of the absolute amount of vit c. This technique in general is called a "titration" and is a standard analytical method. Since you don't have standard solutions, and you probably don't have an accurate method of dropping in the solution, you should be cautious about the conclusions (and analysizing the errors), as staryl13 says. But, the technique itself is not a bad or inaccurate one.

My understanding is that freezing doesn't degrade vit c. However, oxygen in air does. Did you pour out the orange juice in to the container for the freezer? That would have exposed it to a lot of air. Also, you did let the all the juices reach room temperature before you did the tests? If they were at different temperatures that could lead to more variation in the results.

Louise

[streetsidedown313]

Yes, I did expose them all to a temperature of 15 degrees farenheit before the testing. Also, what do you mean by standard solutions? My dropper was pretty accurate too, each drop was equal to one milliliter. Thank you for the information about the oxygen too, that really helps.

[streetsidedown313]

Is there anything in particular I should research on for my report and presentation. Last year I got a very tough judge and I want to know my topic thoroughly.

[Louise]

Yes, I did expose them all to a temperature of 15 degrees farenheit before the testing. Also, what do you mean by standard solutions? My dropper was pretty accurate too, each drop was equal to one milliliter. Thank you for the information about the oxygen too, that really helps.

Glad to hear that you controlled the temp.

If you look at the pdf I linked too, they made a solution of 25 g of vit C in solme amount of water. This allows you to calibrate your system. Then you would be able to say, 'this juice has 13 mg of vit c per serving and this juice only had 5 mg' or whatever.

It is great that your dropper was so reproducible. Usually when chemists do this type of experiment, we use a special dropping system called a buret, which is accurate to .1 of a mL or better.

see:
http://en.wikipedia.org/wiki/Burette

As for what goes in your report and tough judges... The first link I provided the expert provided an outline of what she'd include. I'd recommend knowing the chemistry of your titration (especially if you've already had chemistry in school.) I'd also make sure I tracked down every possible source of error, identified everything that should be a controlled variable and wasn't, and generally be able to convincing explain why your experiment was scientifically rigorous (or what you could improve next time).

The science fair project guide (link in top left corner) also is useful. Even if you know everything, it is worth going through it section by section and making sure you did not forget something.

Good luck!

Louise

[streetsidedown313]

All right. I have been so busy with this project. Thank you about the oxygen on the Vitamin C tip. I learned that colder areas have more condensed air with more oxygen molecules. But what about my testings of microwaving the orange juice and heating it? I can't figure out why they would have a decrease of Vitamin C (considering the room stored orange juice as the control)

[staryl13]

All right. I have been so busy with this project. Thank you about the oxygen on the Vitamin C tip. I learned that colder areas have more condensed air with more oxygen molecules. But what about my testings of microwaving the orange juice and heating it? I can't figure out why they would have a decrease of Vitamin C (considering the room stored orange juice as the control)

Hi!
Microwaving orange juice definitely should cause a decrease of vitamin c, check out this paper...
http://www.sciencedirect.com/science?_o ... d5c6673871
If you're looking for a more concise explanation, look at this link-
http://www.ultimatecitrus.com/vitaminc.html
oxidation occurs at higher temperatures, and this contributes to the vitamin c loss...therefore heating/microwaving the orange juice is going to contribute to a decrease in vitamin c concentration....hope this helps!

[Louise]

I learned that colder areas have more condensed air with more oxygen molecules.

While a set quantity of air will have a smaller volume as it cools, I think this is not the dominant factor in your experiment. [ Note, saying you have more oxygen molecules is confusing, you still have 21% oxygen] (Plus, since water/juice expands in volume when you freeze it, I wouldn't be surprised if you ended up with less air in your container than at R.T.) Since air bounces around more energetically at higher temp, you may also have more reactions at the surface of the juice than at cold temperatures. There are a lot of variables here, of which you've picked one.

The amount of the juice exposed to air (the surface area) is a much larger factor. This is why I asked about pouring. You expose a lot of juice to air when you pour, plus you can include air into the juice, meaning it can oxidize from the inside too. Generally, assuming you have good storage and handling techniques, freezing should not degrade the vitamins in food.

Louise

[jnovak]

Hi
i am doing a project that is very similar to yours and i was just wondering where you got the vitamin c indicator solution and the other stuff.