Real applewood used for BBQs does leave a slight hint of apple in the food that is cooked. I’m not sure what fuel you’re speaking of so I’m not sure about applewood fuel

No. When food is smoked, like salmon or turkey or ham, the apple wood gives it a certain flavor. One could use cherry wood, plum wood, or another fruit tree wood and get about the same results.
One summer I would smoke/cook trout in a barrel with bits of chokecherry wood (smoke) for flavor.