Why is pork, beef and mutton red and chicken pink ?
Why are fish mostly white and salmon orange ?
This is a good question.
The main coloring substance in muscles is myoglobin , which carries oxygen. Muscle fibers can be divided into two types: red muscle and white muscle. Red muscle obtains energy through fat and oxygen, providing lasting power, while white muscle obtains energy through liver glycogen and oxygen (and can perform short-term anaerobic respiration), providing rapid hair growth. force. Different meats have different myoglobin content and show different colors.
The color difference of animal meat reflects the task of this muscle, whether it is sustained or rapid force. Hoofed animals that stand for a long time to support their weight have a relatively high proportion of red muscle fibers in their meat, so they are reddish, especially beef.
The pectoralis major muscle of birds is the muscle used to move the wings and fly. Chickens rarely use this muscle. The proportion of red muscle fibers used for lasting force is very low , so it is light-colored. Chickens are more often standing. When walking and walking, the proportion of red muscle fibers in the thighs is higher and the color is more red. [Note]
Note:
Explain that there are congenital and acquired factors that affect the ratio of red and white muscles. Originally the chicken could fly, but when it was escaping from the enemy, it would not fly for a long time.
The judgment that “chickens rarely use the muscles for flight” not only means that it is artificially raised and does not need to fly, but also that it has accumulated genes encoding “muscles that are not good at long-term flight” in the entire evolutionary history of the species.
The ancestors of ducks are migratory birds, which are very good at endurance flight. Although the artificially raised ducks cannot fly, they retain the genes of their ancestors, so they also cannot fly. Ducks still have more myoglobin than chickens and breast meat. The color is also darker.
I found a picture of duck breast, let’s experience it:
In water, buoyancy will support your body weight and you don’t need to exert sustained force, but the resistance in water is greater than in air, so you need to exert force quickly. Therefore, the muscles of fish are generally white in color, with a high proportion of white muscle fibers and a low proportion of red muscle fibers. The red muscle fibers and white muscle fibers are not evenly distributed in the fish meat. The thin layer of muscle close to the fish skin contains more red muscle fibers. The color difference can be detected by the naked eye (the piece of meat circled by blue pen on the picture) . 
With one exception: tuna. In order to migrate long distances, it swims continuously, so the muscles contain many red muscle fibers and are very dark in color. 
Salmon’s strange orange color comes from astaxanthin in the tiny crustaceans it eats. Salmon raised in captivity will have carotene added to the feed to give it a nice color. 
By: The Red Queen
an AI
I can finally eat it clearly!
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