Leaving the pit in...submerging in water...You’ve probably heard all kinds of kooky ways to prevent avocados from browning. But there’s no real secret to it: browning occurs when air oxidizes the fruit’s delicate green flesh. (Yes: avocado is technically a fruit!) So to prevent a cut avocado from turning color, cover the exposed flesh tightly with plastic wrap, or store it cut-side-down on a small plate, and refrigerate until you’re ready to use the rest.