we have an old apple tree with several grafts on it. some of the apples have spots of transparent flesh. not all the apple types have it, but it's common in more than one type. the apple it's most consistent with is a very old variety, don't know the identity. is it a disease? thanks!
Douglas County Oregon
I have seen apples, especially light skinned ones, that have this problem. If it seems to happen most every year it usually is a virus disease and there is no cure. If this problem happens just on occasion it is probably being caused by high temperatures and maybe some moisture stress. If you would like to bring a few samples by our OSU Extension office we can take a closer look and be a little more certain. Our office is next to the courthouse in Roseburg in the church annex off Fowler St.
After getting your response about the kids liking to eat the white spots I realized this variety could just be left on the tree too long. Many varieties will get water core if left hanging too long. Fuji and Golden delicious do this. This usually happens in the center of the apple and not on the outside like the picture you show. The water core gets very sweet but those apples wont store long. Your apple may be getting this water core effect on the outside too.