The iconic “lobster red” representing these special and tasty sea creatures is very common. But, in their natural environment, lobsters are usually dark blue or black. Why do they change color when cooked?
It is no mystery that those animals that live inconspicuously on the seabed are more likely to survive and pass their genes on to offspring.
Lobsters live in rocky or muddy areas and have a specialized blue pigment to blend in with their environment.and avoid falling under the watchful eye of cod, haddock – which looks a lot like cod – and other fish that enjoy eating lobster for dinner.
However, as any lobster connoisseur knows, these crustaceans turn bright red when cooked. Why does this dramatic color transformation occur?
Scientists have been trying to understand this pigment change since the 1870s.It took more than a century before biochemistry hit the mark. The key to lobster camouflage is the product of two molecules:a protein called crustacyanin and a carotenoid (a pigment responsible for bright red, yellow, and orange hues) called astaxanthin.
Lobsters cannot make their own astaxanthin, sothey get it from their diet.It is similar to the beta-carotene of plant species such as tomatoes. When a lobster eats astaxanthin (from shrimp, for example),your body absorbs it.
Although it is not a simple process. Astaxanthin is red, but it makes live lobsters bluish-green in color. It wasn’t until 2002 that researchers discovered that the protein crustacyanin changes the color of the pigment astaxanthin by twisting the molecule and changing the way it reflects light. Becausewhen this protein is bound to crustacyanin, it turns blue.
Cooking lobsters
When lobsters are heated to high temperatures, whether boiled, baked or grilled, the crustacyanin releases astaxanthin, allowing the pigment to unwind and show its true color: red.
As the lobster heats up, the crustacyanin molecules lose their shape and rearrange themselves in different ways; This physical change in the shape of the protein has a noticeable effect on the color of the lobster.
Crustacyanin is not heat stable, so placing it in a pot of boiling water or on a grill relaxes its bonds with astaxanthin, unravels, and lets the pigment’s true deep red color shine through.
Scientists have clarified the chemistry of this curious color transition, but they still don’t fully understand the physics of how crustacyanin can temporarily and reversibly turn a red pigment blue. Various research groups are using a variety of techniques to discover how crustacyanin and astaxanthin work together to reflect blue light.
It is estimated that 1 in 100 million lobsters are albino and do not have pigments in their shells. When cooked, they will appear the same color: a ghostly gray-white.
A curiosity: The proteins that mask the pigments not only dissolve in the presence of heat, but also dissolve thanks to the acids and fats inside animals such as flamingos during digestion. The released proteins give the feathers of the birds that soft and characteristic pink hue.
