Oxidation - in other words, browning of, say fruits such as apple, pear, etc.
How can we avoid oxidation so that apple looks fresh and white? The cheap answer to your question is salt.
There are different acidic chemicals available, but the simplest one is salt - at least, that's what I always have in my kitchen.
This is a great tricks for people who wants to bring sliced apple to school, work, or on a picnic.
What you need:
ca. 5 dl water
1 tsp salt
This is what you need to do.
Dissolve salt in the water.
After slicing apple, soak them (just to coat the apple - no need to leave them for a long time) in the salt water.