Because of the large amount of oil used in fried food and the high temperature, it will cause fat oxidation, and some substances harmful to human body will be produced in the process of fat oxidation, such as decomposition products of hydroperoxide, dimer and so on.
These substances will slowly move to the liver and other organs after being absorbed by the digestive tract, causing chronic poisoning. At present, some studies have found that polymers produced by fat oxidation are at risk of teratogenesis and cancer.
At the same time, fat oxidation will also promote cholesterol oxidation and produce some cholesterol oxidation products. Cholesterol oxidation products can cause cytotoxicity, oxidative DNA damage, carcinogenicity and mutagenicity in human body, and also cause vascular intima damage, induce chronic diseases such as atherosclerosis and neurasthenia, which is also a great potential threat to human health.
In addition, the study found that the longer the heat preservation time of fried food, the higher the temperature, the more serious the fat oxidation will be, so from the health point of view, it is not good for health to keep fried food for too long.
Therefore, for fried food, fat oxidation is an important index to be concerned about. At present, China's national standard "GB 16565-2003 Hygienic Standard for Fried Snacks" stipulates the fat oxidation of fried snacks (referring to all kinds of shaped and packaged snacks made of flour, rice flour, beans, potatoes, vegetables, fruits and nuts as the main raw materials by frying according to a certain technological formula). The problem of fat oxidation also exists in McDonald's meat fried food, but there is no clear standard in China at present.
In recent years, fried food has been criticized for its high fat and high energy. In fact, from the perspective of fat oxidation and cholesterol oxidation, fried food is also bad for health. Moreover, the fat oxidation and cholesterol oxidation of this kind of fried food stored in heat preservation are more serious, so it is not suitable to eat it in large quantities for a long time.