Yesterday for dinner I made apple pancakes. I cut the apple into small pieces (with the skin on) and just put it into my pancakes batter. The skin was dark red. After cooking it, everything was looking fine.
Now the next morning, I took out the pancakes from the fridge (on a plate covered with aluminium foil) and noticed that the apple skin turned blue/purple-ish. The apple flesh still seems normal (white/yellow), so I'm confident it is the skin that was originally dark red.
It seems safe to eat, smell and taste are completely fine. I mean it's only been 1 single night after all.
So why did this happen?
I've never heard of this. I've baked apple cake before (with skin) and it never turned blue-ish even after days.
The recipe I used includes flour, sugar, baking powder, salt, eggs, oat-almond milk, molten butter and 1 big apple.
After closer inspection it does look more grey-ish with dark purple-ish around the edges.
Unfortunately I can't provide images as the pancakes are long gone.
Oh and as someone has mentioned, the pancake interior around the apple piece was coloured purple-ish. As if some of the color of the apple skin "leaked out".