can i open a tub of a protein powder and put in a other plastic bag while flying to china?

I am planning to buy 4 tubs of whey protein (worth 200$) . the Tubs are big to fit so i want to open it and put it in a plastic bag and put in my luggage. would there be any problem in airport? Proteins are usually expensive in CN and mostly fake, so i wanna bring it from US while travelling. I am a student here , will be more for one more year.