I don't see it as any different to chopping up a load of fruit to keep in the fridge, or to take to work. And if that's the case, then berries wouldn't be free because they don't exactly take alot of prep work!?
Tinned fruit is synned because it actually is cooked slightly, something to do with the canning process.
I can't actually put it into te syn calculator because there is no option to use fruit as a free food