Buzz
Although crabs and lobsters may appear a vibrant red on your plate, they are typically brown, olive-green, or gray in their natural habitats (especially in the mid-Atlantic U.S.; crustaceans from warmer regions may display a variety of vibrant colors). This striking color transformation during cooking happens because of the way certain biochemicals within the shellfish react to heat.
Crabs and lobsters contain a pigment known as astaxanthin in their shells. Astaxanthin is a carotenoid pigment that absorbs blue light and reflects a red, orange, or yellow color. While the crustaceans are alive, astaxanthin is tightly bound by a protein called crustacyanin. This protein binds so strongly that it distorts the pigment and changes how it absorbs light. As a result, the astaxanthin-crustacyanin complex creates a blue-green hue.
When a crab or lobster is cooked, the bonds between crustacyanin and astaxanthin break apart. Since crustacyanin isn’t heat-resistant, the heat causes it to release its hold on astaxanthin, allowing the pigment’s true red color to emerge.
Approximately 1 in 100 million lobsters are albino, lacking any pigments in their shells. These rare lobsters will be cooked and served in the same ghostly gray-white hue they had when they entered the pot.
Shrimp, like lobsters, contain carotenoid pigments in their shells and flesh, which remain hidden until heat is applied. But how do flamingos, who consume a diet rich in carotenoid proteins but never have access to a kitchen, develop the vibrant pink color from the pigments in their food? The proteins that normally mask the pigments unravel and dissolve inside flamingos, aided by the acids and fats during digestion. This process releases the pigments, which then give the birds' feathers their soft pink color.
