What a nose on you, Kaneki boy: he'll be able to sense the heart is not human (although the shape will suggest to the... veteran cannibal that the organ is humanoid.)

If Kaneki is able to distinguish granular details through scent or sight, he can also notice that the heart is:
— animal, in the sense that it is not mechanical and that it once belonged to an organism
— reanimated
— functioning even now, in the absence of a system that would keep it operational