The Real Reason Cut Potatoes Sometimes Turn Pink
Years before many of us even think about stepping into the kitchen, we are taught that discolored foods are usually not safe to eat. Browning fruit and vegetables and meat with a gray tinge usually cause a moment of pause when cooking or eating, but not all discolorations mean that food is unsafe to eat.
According to Business Insider, bruised, browning, or scarred fruits and vegetables, and even fading or darkening meat, are "generally harmless." Bruising can be attributed to produce being squished in transit, and discoloration may be caused by exposure to oxygen. While the discolored produce mentioned above is considered generally harmless, Business Insider notes that other items like green potatoes are unsafe to eat because they contain toxins that cooking can't eliminate. On the flipside, cut potatoes that turn pink are perfectly safe to eat, so let's get into why this phenomenon happens in the first place.
A chemical reaction causes pink potatoes
According to The Kitchn, when a potato is cut, the cell walls that keep everything "nice and tidy" within the potato are disrupted. The phenols and enzymes of the potato interact with oxygen, and that creates a chemical reaction that results in pink potatoes. The more a potato is cut, the more reactions begin to happen. If you need a more vivid image to go along with the science, one The Takeout writer described walking in on a potato blood bath after prepping potatoes for hand-cut fries and soaking them in water. When they removed the potatoes from the "potato blood water," the spuds themselves looked perfectly fine. They were able to transfer the potatoes to a new bucket of water with no one noticing the difference. The Takeout attributed the severity of the reaction to rushing the prep. So, home cooks working with a smaller batch without time constraints shouldn't run into quite the same issues.
Even though pink potatoes are perfectly safe to eat, if you wish to slow down the reaction, The Kitchn suggests using a sharp knife, using the potatoes right away, or submerging them in cold water.