Why Lobster Turn Red When Cooked

Typically, the exoskeleton of most crustaceans (including crabs, lobsters, crayfish&shrimp) are made up of several pigments, one of which is a carotenoid called astaxanthin, which provides a reddish tint.

At normal temperatures and when alive (in other words, when we’re not dumping them in boiling water or grilling the poor guys), the astaxanthin pigments are hidden because they are covered with other protein chains that give their shells the bluish-gray or brownish-green color we see.

Exposure to heat destroys this protein coating,while the carotenoid pigment, astaxanthin still remains stable. So when you cook a crab or lobster or its other tasty crustacean friends, the heat breaks down all the we see in cooked lobsters, crabs, and crayfish or the reddish-orange color of cooked shrimp.

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