This is after an impressive two hours.
The salt interferes with the apples oxidation when cut.
Use 1/2 a teaspoon of salt in 1 cup of cold water.
This tip works for pears as well.
If youd like a sweeter option,weve found a honey bath to be effectivein preventing browning as well.
The Best Way to Prevent Apples and Pears from Browning| Serious Eats