Why does blueberry milkshake turn black?

Blueberry milkshake turns black because blueberry juice is dark blue. Blueberry milkshake can protect eyes, delay aging and enhance resistance. Blueberries are rich in vitamin C, pectin, anthocyanins and other essential nutrients. Blueberries are listed as one of the five healthy foods for human beings by the International Food and Agriculture Organization because of their edible and medicinal effects.