While they might be bright red when they hit your dinner party denture , crabs and lobster are normally brown , olive - green or grey when animated and in the state of nature ( at least in the mid - Atlantic U.S. ; crustaceans farther in the south amount in avarietyofvibrantcolors ) . The dramatic colour variety during cookery has to do with the way sure biochemicals inside the mollusc react to heat .
lobster and crabs have a pigment call astaxanthin in their shells . Astaxanthin is a carotenoid paint : absorbing gloomy light and appearing flushed , orangish or yellow in colour . While the crustacean are alive , astaxanthin lie wrapped in the tight embrace of a protein called crustacyanin . The protein holds the pigment so tight , in fact , that it ’s flattened and its light - absorption property are changed . The astaxanthin - crustacyanin complex then twine up throw off a bluish - immature color .
These biochemical cuddle buddies get separated when a crab or lobster is fudge . Crustacyanin is not heat - stable , so introducing it to a boiling tummy of water or a grille causes it to relax its Julian Bond with astaxanthin , unravel and countenance the pigment ’s true bold red coloring glow through .
An forecast 1 in 100 million lobsters are albino and do n’t have any pigments in their shell . They ’ll go cooked to the dining way the same colour they went live into the stool : aghostly gray - lily-white .
Shrimp also have carotenoid pigments in their shell and flesh , and these are also shroud until they ’re relinquish by oestrus . So how do flamingoes , with diet heavy with carotenoid protein but which usually do n’t have kitchen access , take on the bright pink of their dinners ’ pigments without cooking them ? The protein that mask the pigment not only unscramble in the presence of passion , but also resolve thanks to the acids and fatness inside flamingo during digestion . The freed proteins then give birds ’ feathers a soft pinkish chromaticity .
