The orange is from the orange being slightly old, methinks. That happens to my lemons if I have them in the fridge for too long. A beautiful shot; the forground blur is lovely, and the light bounces off of subject very nicely.
Definitely has the feeling of a classic still life and I agree the front slice is a bit too oof for me too, but wow! what colours and tones to get in-camera! That's the mark of someone who knows their stuff :)
I love the lighting and the background is excellent. In fact not much here I don't like. It's great as it is, although I probably couldn't resist the temptation to play with some textures and layers :)
I like the one on the right. A beauty with nice focus and soft light. The front one is too much OOF for me. The half lemon has some strange (orange) colors. Nothing wrong with the background and the light here!