When cooking oil is heated above 200℃, the fat-soluble vitamins contained in the oil are destroyed, other vitamins (especially vitamin C) are also destroyed in large quantities, and various fatty acids needed by the human body are also oxidized in large quantities, and the nutritional value of the oil is greatly reduced. Therefore, although the dishes fried in hot oil are crispy and delicious, the nutritional value of the dishes is greatly reduced.
At the same time, if the oil temperature is too high, it will also produce a lot of lipid peroxide, which is harmful to human body. This is because lipid peroxide will not only destroy a lot of vitamins in food in gastrointestinal tract, but also hinder the absorption of protein and amino acids. If people eat this lipid peroxide for a long time, it will accumulate excessively in the body, and some metabolic enzyme systems of the human body will be destroyed, which will eventually lead to premature aging of the human body.
Edible oil-Animal oil or vegetable oil consists of glycerol and fatty acids. The melting point of vegetable oil is generally lower than 37℃, and the melting point of animal oil is generally 45-50℃. Therefore, when the oil temperature is above 200℃, the glycerol in it decomposes, which will produce a gas called "acrolein", which is the main component of oil fume. Acrolein is a kind of irritating substance that is harmful to human respiratory tract, digestive tract and eyes. It can not only cause tears, choking cough, anorexia, dizziness and other symptoms, but also directly damage human cells and become one of the important adverse factors that induce cardiovascular and cerebrovascular diseases and digestive tract diseases. It can be seen that high oil temperature during cooking is really bad for health.