In particular, trace elements in viscera are very rich, such as pig liver and duck liver, which are rich in iron, and chicken blood and duck blood are rich sources of iron. Beef and liver contain zinc, while pork and poultry are good sources of zinc. The contents of chromium, selenium, cobalt and molybdenum in animal liver are also very rich.
protein
The protein content of lean meat food is about 10% ~ 20%. Lean pork contains protein 10% ~ 17%, while fat pork contains only about 22% protein. Lean beef contains about 20% protein, and fat beef 15. 1%. Lean mutton 17.3%, fat mutton 9.3%; Chicken contains 23.3% protein; Duck meat16.5%; Goose 10.8%.
The amino acid composition of protein in meat, poultry and fish is close to the essential amino acid pattern needed by human body, so its biological value is above 80%.
In cook the meat, a part of protein can be leached and dissolved in the broth, and a part can be hydrolyzed into amino acids, making the broth delicious and nutritious.
Meat mixed with cereals, beans and other plant foods can supplement the essential amino acids in protein and improve its nutritional value.
The fat content of fat meat is about 10% ~ 36%, and the fat of fat meat can reach 80%. Animal meat fat has a high melting point, mainly containing triglycerides with more saturated fatty acids, and a small amount of lecithin, cholesterol, free fatty acids and fat-soluble vitamins. The special smell of mutton is related to its bitterness and nonanoic acid. Poultry meat has low melting point and saturated fatty acid content, which is easy to digest and absorb; The fat content of chicken is about 9.0%, which is higher in waterfowl such as geese and ducks, about 19.0%, and linoleic acid accounts for about 20% of total fatty acids.
The cholesterol content in fat meat is as high as 109, and that in lean meat is 8 1. Liver and kidney are 200 ~ 400, and the highest content in brain is about 2600, so patients with hyperlipidemia and atherosclerosis should not eat more animal fat and viscera.
mineral salt
Inorganic salts mainly exist in lean meat and internal organs. Although the calcium content in lean meat is low, its absorption rate is high.
It has been proved that beef, pork, mutton and chicken can increase the absorption of iron. The main form of iron in meat is heme iron, which has high bioavailability and is not interfered by other factors in food. The so-called "meat factor" in meat food can increase the absorption of inorganic iron except heme iron in food. Animal foods such as livestock and poultry meat are generally good sources of zinc, but phytic acid in many plants is combined with zinc, which makes it impossible to use.
vitamin
There are many thiamine (vitamin B 1), riboflavin (vitamin B2) and nicotinic acid (vitamin PP) in animal muscle tissue. Animal food is a good source of fat-soluble vitamins. The liver is rich in vitamin A and contains a small amount of vitamin D. The content of riboflavin in the liver is 15~20 times higher than that in muscle tissue, and the content of nicotinic acid is 4 ~ 5 times higher. The liver also contains folic acid and vitamin B 12. The content of thiamine in poultry meat is less, but the content of nicotinic acid is higher.
The carbohydrate content in meat is low, about 0.3% ~ 0.9%, and the content in liver is higher than that in other tissues, mainly in the form of glycogen and lactic acid. Glycogen has an important influence on the flavor, quality and preservation of processed meat. If healthy animals are not overtired before slaughter, the glycogen content is high. After meat was stored, the content of glycogen decreased and the content of lactic acid increased correspondingly, so the pH value of stored meat gradually decreased.