What causes raw potatoes to turn black?

Raw potatoes turn black when exposed to oxygen. The enzyme polyphenol oxidase, which is present in the potatoes, reacts with oxygen to produce melanin, a dark pigment. This process is called enzymatic browning.

The rate at which potatoes turn black depends on a number of factors, including the temperature, the humidity, and the type of potato. Potatoes that are stored in a warm, humid environment will turn black more quickly than those that are stored in a cool, dry environment. Russet potatoes are more likely to turn black than other types of potatoes, such as white potatoes or red potatoes.

To prevent potatoes from turning black, you can store them in a cool, dry place. You can also wrap the potatoes in plastic wrap or aluminum foil to prevent them from coming into contact with oxygen.