wow, that's tough. maybe its not the food, and its probably not you. some parents are just like that. i know some of my friends whose parents will give the meanest stare and ignore them completely when they come to visit but they come around with time. i think another thing with asian parents, esp if they're really traditional is to not walk into the guy's room and close the doors or get too touchy-feely in front of them. that doesn't and will never go down well lol.
maybe ask your boyfriend if he knows what it is?