Have you ever wondered why lobster, shrimp, crab, crawfish, and other crustaceans turn a bright orange-red when cooked? No, they aren't blushing from embarrassment. It's a simple question answered with science.Crustaceans have exoskeletons, and while the animal is in the sea, the exoskeleton primarily has a blue-green to grayish color. The exoskeletons contain a carotenoid
. Carotenes are pigments, and astaxanthin is the same carotene that gives salmon its color. When crustaceans are uncooked, the astaxanthin pigments are hidden because they are covered with protein chains; these protein chains give the shells their bluish-gray color. Heat destroys the protein coating, and when the animals are cooked, the astaxanthin molecules are released, thus changing the color of the crustaceans.