Huh. That's strange, I distinctly remember his theme never playing.
I think you guys are mistaking 'white rice' with 'fried rice'...'white rice' was in Japan's MKC, which I'm sure you all know played quite a few times throughout APH.
They usually only ever play the character's MKC when the episode is about them, and so far there's only been one episode about China (Episode 16)...and at the end of that episode, they played Italy's MKC. China's MKC wasn't even out at the time!
*shrugs* But whatever. The main reason why China doesn't have many episodes is because Korea isn't in the anime...
Anyways! Moving onto the actual episode discussion!
I was also kind of disappointed that they didn't play either Liet or Pol's MKC at the end. But I think that might be because of the France/Italy thing at the beginning and end.
EDIT: ROFL, check the date this post was posted, guys. I know about episode 58 of Hetalia/6 of HWS. <3