At last! I finally got around to doing an apple browning prevention experiment! In order to see what works best to prevent the oxidization browning of sliced apples, I treated 6 Granny Smith apple slices each with a different thing suggested to prevent browning - plain water, apple juice, orange juice, lemon juice (in water), Thomas Kemper ginger ale, and Fruit Fresh, and left 1 alone. I labeled them and left them exposed to the air, photographing them throughout an 8 hour period. Here are the results:
The apple I did nothing to has already started to brown. The one dipped in orange juice hasn't started browning, it just has a slight tinge from the juice itself.
1 hour exposed to the air.
The apple I did nothing to is quite browned, the one dipped in water slightly less. The apples dipped in juices have about the same degree of browning. Surprisingly, the apple dipped in ginger ale has browned as much as if not more than the one dipped in water! The Fruit Fresh apple has not changed.
4 hours exposure.
This is probably what an apple I sliced in the morning would look like by lunch time for my kids. The apple I did nothing to has browned considerably - no surprise there. The apple dipped in ginger ale is a close second though! My kids wouldn't want to eat either of those. The apple dipped in water has browned less than the ginger ale one, but more than those dipped in juices. The juice apples are very similar - the lemon juice apple does seem to have browned a little bit less than the apple juice and orange juice ones - all 3 would probably still appeal to my sproutlets. The Fruit Fresh apple is almost unchanged :)
8 hrs after being sliced. The Fruit Fresh apple is the clear winner - it's still very fresh-looking 8 hours later, as advertised. The orange juice apple comes in second place, it browned visibly less than the lemon and apple juice ones. The apples dipped in water and ginger ale did not fare very well, by now they are nearly as browned as the apple that had nothing done to it.
Here are the apples in order of browning, most to least. Fruit Fresh wins!
In conclusion, I'd say that the best way to keep apples from browning is to use a product made to keep produce fresh. My jar of Fruit Fresh was pretty inexpensive (about $3), can be stored in the cupboard, and leaves no taste on the fruit. If I didn't have that, a juice containing citric acid would be my next choice. Soda pop containing citric acid (like ginger ale or Sprite) would not be my choice - dipping the apple slices in plain water worked better, without adding any sugar, and is more practical for me since we don't regularly have soda pop in our fridge - but even if we did I wouldn't want to open a whole bottle/can just to brush a little on my kids' fruit ;)
* I should also add that these apple were dipped, not soaked, in the product used. I have soaked apples in just plain water for 10 minutes or more and then sealed them in an airtight container and had them look perfectly fresh hours later. Preventing any air exposure - by soaking then sealing the apples in an airtight container - is the best way - I don't always have time to soak though - sometimes I want to slice, pack, and go - and sometimes I am multi-tasking while making lunch and the apple slices may be exposed to air for a bit - and not all my containers keep all the air out either. That's why I tested these in open air.