Science Buddies: "Ask an Expert"

I did my science experiment on apple browning. I thought that lemon juice would be the best liquid to keep sliced apples from turning brown, but salt water actually worked the best - the apples didn't turn brown at all. Do you have an explanation why salt water, which isn't acidic, would stop apple browning better than lemon juice, which has a much lower pH? Thanks for your help.

Hi!
The reason behind this phenomenon is due to something called oxidation which causes the apples to become brown. As noted in the following article, things like lemon juice prevent this oxidation process from happening, so the apples will brown less quickly.

http://www.ehow.com/how_2386223_keep-cu ... rning.html

Here are some other quick links that you might want to read through:

http://www.blurtit.com/q308049.html

http://www.associatedcontent.com/articl ... rning.html

People tend to get varied results between the salt water and the lemon juice:

http://www.exampleessays.com/viewpaper/40933.html

The most likely reason why you saw that the salt water did better is because salt water has the ability to pull away the water from a sample, thus exposing the sample to less oxygen, so less oxidation occurs. Hope this helps!

Thanks for your reply and for the helpful links!

My mom always soak cut apple slices in salt water.