Why did the apple skins turn blue/purple-ish in my apple pancakes the next day?
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".
Best Answer
I feel fairly confident that what you see is anthocyanins (naturally present in apple skin) reacting with some leavening in your pancakes.
Here's a link that explains in more details, but I'll summarize: https://extension.psu.edu/fruit-color-promoting-red-color-development-in-apple
Anthocyanins are a natural pH indicator present in many fruits and vegetables. Red cabbage and blueberries are common examples. Elderberries and black sweet rice, and even many flowers also contain these compounds.
And they turn red in the presence of acid like vinegar, buttermilk, or fruit juice, and blue in the presence of a base like baking soda or baking powder.
So when you bake or cook with certain fruits that contain anthocyanins, you might be surprised that your blueberry muffins came out green, or that your "purple" rice is hot pink. This is because anthocyanins are water soluble, so they'll disperse throughout what you're cooking easily, and visually indicate the pH. You may even notice a blue shadow in the pancake around or under the apple skins.
But if this is the case you are a-okay. Judging by the contents of the recipe, it only contains a base for leavening, but no acid for it to react with. So it makes perfect sense that your apples, the only acidic component, would react and turn blue. If you want to get more rise, include some buttermilk or lemon juice next time. When it reacts with your leavening you'll get more floof, and your apples will stay red (or pink at least.)
Pictures about "Why did the apple skins turn blue/purple-ish in my apple pancakes the next day?"
Why do apples turn blue?
This is because anthocyanins are water soluble, so they'll disperse throughout what you're cooking easily, and visually indicate the pH. You may even notice a blue shadow in the pancake around or under the apple skins.Can apples turn purple?
Doesn't it look like it's just oozing folklore? Black Diamond apples are a rare variety from the family of Hua Niu apples (also known as the Chinese Red Delicious). The name is a little misleading because they aren't exactly black, but rather a dark hue of purple.Can cooked apples sit out overnight?
The USDA says food that has been left out of the fridge for more than two hours should be thrown away. At room temperature, bacteria grows incredibly fast and can make you sick. Reheating something that has been sitting at room temperature for longer than two hours won't be safe from bacteria.Can you leave apple Crumble out overnight?
According to the USDA, fruit fillings that have been prepared with sugar can be safely left out at room temperature for up to two days. Apple crisp falls into this category, so it doesn't need to be refrigerated if you're going to eat it within that time period.Obsessed Much
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Nataliya Vaitkevich, cottonbro, cottonbro, cottonbro