It's the season to eat crayfish again, crayfish is a delicacy that people love to eat, and it is not a big problem for each person to eat three or five pounds, but why does the cooked crayfish turn red?
Dutch researchers found that interference of cross-paired astaxanthin molecules to change their spectral absorption range is the key to lobster discoloration. Astaxanthin is widely present in algae and arthropods. It is red in itself. But in living organisms, astaxanthin combines with other proteins to form astaxanthin, which exhibits other colors such as blue-purple or turquoise.
Francisco Buda and colleagues at leiden University in the Netherlands found that astaxanthin molecules in pairs of astaxanthin interfere, just as electrical signals from adjacent wires interfere with each other. This interference changes the quantum energy state of astaxanthin molecules, thereby changing the wavelength at which they can absorb light.
Buda explained that the red pigment absorbs the blue and green parts of the spectrum, reflecting red light. When astaxanthin binds to astaxanthin, the absorption range of astaxanthin expands to a longer wavelength (i.e., it absorbs red light), which means that it absorbs most of the visible light, so that the live lobster appears blue-black. When lobster is cooked, the spectral absorption range of astaxanthin narrows, making the cooked lobster appear red.
In layman's terms, when the crayfish is heated, the protein in the body is destroyed and separated from astaxanthin, and most of the other pigments are decomposed when they encounter high temperatures, only astaxanthin is not afraid of heat and will not be destroyed, so the color becomes the original red, that is, the color of the shrimp and crab after cooking.
In addition to heating, strong acid and alcohol strong brine and heavy metal ions can denature proteins, so although shrimp is not cooked, but macerated with salt wine and other maceration will also change color.