Colorful cauliflower can brighten a side dish—but only if it keeps its color during cooking.
Not so long ago, white cauliflower was your only option at the supermarket. Nowadays the produce aisle is aglow with hybrid varieties bred to have high levels of particular naturally occurring pigments. An abundance of carotenoids color orange cauliflower; extra chlorophyll creates green cauliflower, and a plenitude of anthocyanin compounds produces the purple brassica. Color differences aside, we found that they all shared the same mildly nutty-sweet flavor. But does cooking dull their color? We boiled these varieties in water and sautéed them in oil to find out.
The carotenoids in orange cauliflower proved the most stable. These pigments are not water-soluble or sensitive to heat and stayed vibrant when boiled or sautéed. Though the chlorophyll in green cauliflower is heat sensitive, the vegetable turned tender before it faded or turned brown, whether boiled or sautéed. The water-soluble anthocyanin compounds in purple cauliflower were the most sensitive; when we boiled the vegetable, they leached into the water and dulled its color if cooked past crisp-tender. Happily, sautéing didn't impact the color at all.
In sum, orange cauliflower will hold its color no matter how (or how long) you cook it and green cauliflower will stay green as long as you don't overcook it. Stick with sautéing purple cauliflower to prevent its color from fading or make sure to blanch it until just crisp-tender.