Science Buddies: "Ask an Expert"

Hello, I am doing a modified version of this project of determining vitamin C content of orange juices through titrations
https://www.sciencebuddies.org/science- ... p044.shtml

in my experiment I am testing the vitamin c content of bananas
the new independant variables are stages of ripeness and organic vs non-organic
the dependent variable will still be the vitamin C content

My question: I understand that vitamin c faces oxidation. However, I am not sure if vitamin C content varies from banana to banana much, but I don't have enough iodine to test this. So, I would like to know which one I should isolate. Should i use different bananas at different stages of ripeness, or should I use the same banana, and then cover the cut area with saran-rap to prevent extra oxidation?

At the moment I think that using different bananas will have less variation in vitamin C levels, but I need your advice. Thanks in advice

Hi,

Here are papers that discuss the variation of vitamin C with ripeness and variation between plants:

http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

http://etmd.nal.usda.gov/bitstream/1011 ... 813008.pdf

http://www.plantphysiol.org/cgi/reprint/39/4/630.pdf

Be aware that even different bananas within a hand or bunch are at different stages of ripeness at any time - one tip off is the variation of color between different bananas in the hand or bunch(how much green shows on the skin).
This paper includes a description of ripening stages:

http://docsdrive.com/pdfs/ansinet/pjbs/ ... 9-1152.pdf

This review paper may also have some useful general information:

http://postharvest.ucdavis.edu/datastor ... 234-17.pdf

I think these papers taken together will let you form an informed opinion of the answer to your question.

I wish you success in your project!

Best regards,

Barrett L Tomlinson