Good idea and composed decently. A ceramic rather than a paper plate would be nore appealing. The left grapfruit top is well focused but little of the rest of the image is. A higher f/stop (narrower aperture) would allow all to be in focus. If it was your intention to make the rest of the composition soft focused than a wider aperture and shallower DOF would have worked better.
You need to do some clean-up. The seeds and bits of grapefruit on the plate and knife are not very attractive, nor is the half of the grapefruit that has been sectioned.