I can't really tell where that white stuff is coming from in your pictures, but if it's coming out it's mouth then it's just pooping, for lack of a better description.
But if it's coming from the tissue itself, that's not good. It almost looks like the tissue is kind of white and damaged at that one folded spot in a couple of your pictures - the 2nd and 3rd pictures, specifically. Am I seeing that correct? If so, looks like that area has receeded quite a bit compared to the rest. Maybe some local tissue damage during transport?
Only thing you can really do is keep your water parameters top notch and don't mess with it by moving it around a bunch. If the tissue is receeding to the point where it's kind of coming off the skeleton, that's not a good thing. When that happens, things go downhill quick, so you should know in a few days what you're dealing with.