Why do shrimp and crabs change color after they are cooked?

The pigment area of the exoskeleton of shrimp and crab contains a protoastaxanthin, which belongs to carotenoids, which is originally orange-red, but can be combined with different kinds of proteins, and will change to other colors such as red, orange, yellow, green, blue-violet, etc. When the protein is destroyed, denatured, or separated from the original astaxanthin, the color changes to the original orange-red, so the shell of the shrimp and crab will turn red after cooking. In the cortex under the shell of crabs and shrimps, there are many pigment cells, which can show different colors, and with the light and darkness of the environment, these pigment cells can also stretch or contract, when the environment is brighter, the pigment cells will stretch, the color of shrimp and crabs will be more distinct, and when the environment is darker, the pigment cells will contract, and the color of shrimp and crabs will not look obvious.

Under normal conditions, the shells of live crabs and shrimp are turquoise. However, when the crabs and shrimps are put into the pot, most of the pigments are decomposed when they encounter high temperatures, and only astaxanthin is not afraid of heat, and will not decompose when encountering high temperatures, but will show bright red, so the cooked crabs and shrimps will become red.

It's because of the shrimp. Crabs originally contained a substance called astaxanthin. will make the whole look green. When boiling. Because of the oxidation of astaxanthin. So turn red!

Among the carotenoids, the reduction of astaxanthin is the most important, which is the main substance that constitutes the red color of shrimp and salmon Prooriginal astaxanthin exists in the shell of shrimp, because it is combined with protein, so it becomes blue-purple, and once the protein is denatured by heat, it immediately returns to its original red color But when banao xanthin is combined with protein, it is still yellow. Tangerine. or red, which is why some shrimp or crabs are red in their shells when they are alive.

The carapace of shrimp and crab contains a variety of cells with different pigments, among which astaxanthin cells contain the most, and the pigment is destroyed and decomposed at high temperatures, but the astaxanthin cells are not destroyed, so they turn red.

Pigment cells are destroyed by high temperature and decompose, but astaxanthin cells are not destroyed, so they turn red when cooked.

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Analysis: Why do shrimp and crabs 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.

Because the shell of the shrimp contains astaxanthin and astaxanthin, the pigment is active when the shrimp is alive, so it shows blue-black. Astaxanthin is unstable and will be destroyed when it is heated, but astaxanthin is very stable, so it shows the red color of astaxanthin after cooking. This is also true for crabs that turn red after boiling.

Reason: (1) In the shell of shrimp and crabs, there is a bright red pigment called astaxanthin! They 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".

2) Because the heat destroys the pigment, the cooked shrimp turns red! As long as it is soaked or heated with formaldehyde, due to the pigment protein in its organism, it is denatured when heated, and the pigment that was originally bound to the protein "escapes" out, revealing red.

Why do shrimp and crabs turn red when cooked? Why can't the fish?

Crab is a kind of food that many people love to eat, and it is delicious and mouth-watering. Interestingly, the back of a live crab is blue-black, but once cooked, it turns a vivid orange-red.

It turns out that crabs belong to the crustacean family, and their color is mainly determined by the pigment cells distributed in the dermis below the carapace. Of these pigment cells, the cells containing astaxanthin are the most numerous. Astaxanthin is a carotenoid, which is originally orange-red and can be combined with different kinds of proteins to change to other colors such as blue-violet or turquoise.

When the crab is heated, the protein is destroyed and separated from astaxanthin, while the other pigments are destroyed and decomposed at high temperatures, only astaxanthin is not afraid of high temperatures and is not destroyed, and when other colors disappear, the red color is revealed. So, the boiled crab will turn red.

On the formabetha of crabs, the distribution of astaxanthin is also uneven. Wherever there is a lot of astaxanthin, such as the back, the crab looks extra red after it has been cooked; In places with less astaxanthin, such as the lower part of the crab legs, the red color is lighter; Since there is no astaxanthin in the abdomen of crabs, it will not turn red no matter how many times it is steamed.

The color of the crab's body is mainly determined by the pigment cells in the carapace dermis. In the dermis of the crab carapace, there are various pigment cells, but most of them are blue-black, which is why live crabs are blue-black. Among these pigment cells, there is a pigment called astaxanthin, which is usually mixed with other pigments and cannot show its bright red color, but after boiling, other pigments are destroyed and decomposed, but it is not afraid of high temperatures, so the carapace of the crab shows the red color of astaxanthin.

However, in the dermis of the crab carapace, the distribution of astaxanthin is uneven. Therefore, you will find that after the crab is cooked, it is not red all over, 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 there is no astaxanthin in the abdomen of the crab, no matter how many times it is steamed, it will never turn red!

In addition to crabs, the discoloration of shrimp after cooking is also due to the above-mentioned reasons.

Because they have pigment in their body, as long as they are boiled or scalded with hot water, the pigment will be stimulated back?