Blue is a popular color for many snack foods, from lollipops to yogurt. These treats get their vivid hue from artificial dyes. But “there’s been a large push to get rid of synthetic ingredients in food,” says Pamela Denish, who studies biophysics at the University of California, Davis. Her lab has been researching a natural way to turn food blue—using cabbage!
Red cabbage gets its color from a class of pigments called anthocyanins. Denish’s team found that a certain enzyme—a biological molecule that speeds up a chemical reaction—can convert red anthocyanins in cabbage into blue ones. That allows the scientists to produce big batches of blue dye—no lab-made chemicals needed.