Does green raw shrimp turn red when cooked? Why? Does it have anything to do with chemistry?

In the dermis of shrimp and crab carapace, there are various pigment cells, but most of them are blue-black, in these pigment cells, there is a pigment called astaxanthin, usually it is mixed with other pigments, can not show the bright red color, but after boiling, other pigments are destroyed and decomposed, but it is not afraid of high temperature, so the carapace of shrimp and crab will show the red of astaxanthin. However, in the dermis of shrimp and crab carapace, the distribution of astaxanthin is uneven. Therefore, you will find that shrimp and crabs are not red all over the body after cooking, and in places where astaxanthin is more distributed, such as the back part, it will appear extra red, while in places with less astaxanthin, such as the lower part of the crab legs, the red will be lighter.

Since the abdomen of a crab does not have astaxanthin at all, no matter how many times it is steamed, it will never turn red.

Seafood is not very safe now, it is recommended to eat less.

I don't think it's okay, the color of its meat from raw to cooked.

Why do shrimp and crab turn red when cooked? It's about chemistry. It turns out that there is a bright red pigment in the shells of this cooked shrimp and crab.

If the red shell of a crab is immersed in a chemical called acetone, the pigment will dye the acetone a beautiful orange red, and the shell will fade and lighten. Later, someone isolated this pigment from lobster eggs and called it astaxanthin.

Astaxanthin-containing animals are not only shrimp and crabs, but many crustaceans also use astaxanthin to dress themselves. Some small shells mainly contain fenocyanins, and some crabs contain pterenthin. These pigments, including astaxanthin, have a similar structure to carotene, and they are abundantly and widely distributed in nature.

The chemical name is ketone carotenoids, and they are the main components of the pigments contained in animals such as "shrimp soldiers and crabs".

The body color of living crustaceans varies depending on the species and the environment, but no matter what the body color of the living "shrimp soldier crab" is, as long as it is soaked or heated with formaldehyde, it will also turn red. This is because the pigment protein in the organism is denatured when it is heated, and the pigment that was originally bound to the protein "escapes" out, revealing the red color. In addition, after death, shrimp and crabs, due to the denaturation of proteins in the body, the pigment escapes, and the shell will also turn red.

The exoskeleton of the shrimp contains an orange-red pigment (alias: reduced astaxanthin), which is a kind of carotenoid, after this pigment is combined with protein, it will turn into yellow, orange, purple, green, blue and other colors due to different proteins, when the protein is destroyed or denatured or the protein is separated from the pigment, the color will change back to the original orange-red, and the shrimp will turn red when cooked due to protein denaturation.

Denaturation of proteins: Under the action of certain physical and chemical factors, its specific spatial conformation is destroyed, that is, the ordered spatial structure becomes a disordered spatial structure, which leads to the change of its physical and chemical properties and the loss of biological activity, which is called the denaturation of proteins. 〕

The color of the body surface of shrimp and crab is mainly determined by the pigment cells in the dermis of its crustacea, which are basically blue-black, and contain a pigment called astaxanthin.

Astaxanthin usually binds to proteins, so it does not appear red. When the shrimp is still alive, the astaxanthin in the body is tightly wrapped by "chitoside" (a special protein) and will not leak out.

When the shrimp is heated at high temperature, many pigment substances will be destroyed, because astaxanthin is more stable and not easy to be destroyed at high temperature, so at this time, astaxanthin can be separated from the protein, thus showing red.

1. Astaxanthin, also known as astaxanthin and astaxanthin. In 1933, a purple-red crystal was extracted from shrimp, crab and other aquatic products, and it was later determined to be a carotenoid closely related to astaxanthin, so it was named astaxanthin.

Carotenoids are the main pigmenting substances in aquatic animals, and astaxanthin accounts for most of the carotonoids in aquatic animals, so it can be said that astaxanthin is the main pigment substance in aquatic animals.

Astaxanthin is the end point of carotenoid synthesis, it can be stored directly in tissues without modification or biochemical transformation after entering the animal body, and has a strong pigmentation ability, so that the ** and muscles of some aquatic animals appear healthy and bright color, so that poultry eggs and poultry feathers, **, feet, and items are healthy golden yellow or red.

2. Astaxanthin is fat-soluble, insoluble in water, soluble in organic solvents, and widely exists in the biological world, especially in the feathers of aquatic animals such as shrimp, crabs, fish and birds, and plays a role in color development.

3. Natural astaxanthin is a carotenoid with strong antioxidant properties, which has the functions of antioxidant, anti-aging, anti-tumor, and prevention of cardiovascular and cerebrovascular diseases. Internationally, it has been applied to health food, high-end cosmetics, pharmaceuticals and other fields.

Astaxanthin itself is not stable, easy to oxidize, easy to decompose when seen in light, and its activity is mostly retained in the form of astaxanthin gel on the market.

<>1. The exoskeleton of shrimp and crab contains an orange-red pigment, which is a kind of carotenoid, after this pigment is combined with protein, it will turn into yellow, orange, purple, green, blue and other colors due to the difference in the white matter of the egg shirt, when the protein is destroyed or denatured or the protein is separated from the pigment, the color will change back to the original orange-red, and the shrimp will turn red when cooked due to protein denaturation.

2. In addition to heating and burying filial piety, strong acid, concentrated alcohol, concentrated brine and heavy metal ions can denature the protein, and the positive liquid cavity will change color even if the shrimp is not boiled but impregnated with salt and wine.

1. The exoskeleton of shrimp and crab contains an orange-red pigment, which is a kind of carotenoid, after this pigment is combined with protein, it will turn into yellow, orange, purple, green, blue and other colors due to different proteins, when the protein is destroyed or denatured or the protein is separated from the pigment, the color will change back to the original orange-red, and the shrimp will turn red when cooked due to protein denaturation.

2. In addition to heating, strong acid, concentrated alcohol, concentrated brine and heavy metal ions can denature the protein, so although the shrimp is not boiled, it will also change color when impregnated with salt and wine.