It fundamentally represents knowledge and the freedom that is associated with it.
With knowledge and freedom we are in a position to make positive or negative choices.
The apple should be interpreted with the consideration of all the other details in the dream.
Is the apple a symbol of positive movement and spiritual and emotional liberation, or is it a symbol of runaway passions and the resulting negativity?
Are you giving into temptation and making hurtful choices or are being wise and enjoying the fullness of life?
Depending on the context of the dream, an Apple can signify love (if the apple is fresh and given to someone), guilt (only if one associates eating an apple with the biblical reference to the garden of Eden).
In prophetic dreams the apple is considered to be a very good omen, but the interpretation depends primarily on what the details are. If the apples are ripe there is a promise of financial rewards but if the apples were green, bitter, or tainted in some way then you are in danger of losing something through mistake or foolishness that you would have otherwise gained.