As far as I know, fruit is only synned if it's pureed or cooked. If it's chopped or cut in any way, but still left solid it doesn't need to be synned. Though, as with everything, it also depends on what you plan to do with it once it's been grated.
I have been making rolled oats soaked in grated apple, natural fromage frais, and some red berries mixed in for my breakfast- you just leave it overnioght, no cooking required! It yummy, but I wamted to check I wasn't using syns without realising!