Science Buddies: "Ask an Expert"

we did the Vitamen C project last year comparing amt in fresh versus frozen versus bottled.
we need to buy new Lugols solution for this years project which is determining which fruit(orange,lemon,lime or mango has the most vit c) but I do not know what concentration was in the kit. I need to replace ASAP to do this year project. Also if starch solution runs out where can I buy it. There may be enough and it still is in the date period but again need to complete this in next 1-2 weeks.

I also need to have some help finding info on Vitamen C in various fruits. I can find many sources that tell the amt in different fruits but nothing that really explains why one might have more vitamin c then another. The teacher insists I have some sources to support that oranges will have the most. Can you help me with this?

Hi:

According the Science Buddies write up, here's the info on the Lugol's solution: 2% Lugol's iodine solution (30 mL); also available from Amazon.com

If you need more starch solution, just do a web search for it. Here's Google's results: https://www.google.com/search?biw=1296& ... fd4g&pbx=1

As to why plants have vitamin C in them, you can also search the web for that info. Here are some quotes from Wikipedia:

Ascorbate (the anion of ascorbic acid) is required for a range of essential metabolic reactions in all animals and plants. It is made internally by almost all organisms. Ascorbic acid is associated with chloroplasts and apparently plays a role in ameliorating the oxidative stress of photosynthesis. In addition, it has a number of other roles in cell division and protein modification.

Evolutionary pressures caused various plants to make more Vitamin C than others. Why? I don't know. You can suggest this as an area of further study

Keith