Blueberries are one of the few foods that are truly naturally blue.
The pigment that gives blueberries their distinctive colour, anthocyanin, is the same compound that provides them with incredible health benefits. Studies have shown that anthocyanins have many beneficial properties for our body. That is why they are used in both the food and cosmetic industries (by the way, they are marked with the E163 label).
But the silver coating on the skin is a natural compound that helps protect the fruit. That’s why you should only wash blueberries just before eating them.