Edible oil is nothing more than animal oil and vegetable oil, which is composed of glycerol and fatty acids. The melting point of vegetable oil is lower than 37℃, and that of animal oil is generally 45-50℃. When the oil temperature is above 200℃, the glycerol in it will decompose, producing a gas called "acrolein", which is the main component of lampblack.
Acrolein is an irritating substance harmful to human respiratory tract, digestive tract and eyes, which can cause tears, choking cough, anorexia, dizziness and other symptoms. In addition, due to the formation of "acrolein", oil will also produce a large number of peroxides, which are harmful substances that cause cancer. Therefore, it is advisable to burn the oil to 80% heat when cooking.
Low oil temperature is good, 100 degrees, but it is difficult to control. Therefore, under the condition of not hindering the killing of microorganisms, the rapid frying of fresh vegetables in hot oil can also make the loss of vitamins in vegetables less, of which vitamin C can be retained 60%- 70%, and carotene in riboflavin can be retained more.