The risk of local oil extraction First of all, let's look at the ingredients in the extracted oil. The main component of refined oil is triglyceride. In addition to triglyceride, there are some other components in unrefined pressed oil, such as free fatty acid, phospholipid, oil residue, moisture, polycyclic aromatic hydrocarbons, benzo (a) pyrene, aflatoxin and pesticide residues that may be brought in during planting, harvesting, drying and storage. The above non triglyceride components will have many adverse effects on the oil itself: 1. The influence on the shelf life. The existence of free fatty acids, phospholipids and water makes the oil unstable and easy to oxidize, which shortens the shelf life. 2. Impact on smoke point Oil heated to the temperature of continuous smoke, called smoke point, smoke point is mainly caused by impurities in the oil. In general, the crude oil starts to smoke when heated to 140 ~ 150 ℃, while the smoke point of refined primary oil can be raised to above 215 ℃. The composition of lampblack is complex, mainly including aldehydes, aromatic compounds, furans, dialkyl and other harmful compounds. Acrolein, for example, is a highly irritating substance that can damage the respiratory system and eyes. In addition, studies have shown that cooking fume is related to female lung cancer, cooking fume is an important risk factor of female lung cancer in China. Considering that Chinese people generally like to heat the oil to a very high temperature when cooking, the health hazard of this kind of local oil is more obviou
For some people who like the taste of oil, refined first-class oil is light and tasteless, which is really not in line with the taste. In this regard, it is suggested that they choose small packaging products of grade 4 oil or grade 3 oil. At present, the edible oil is divided into four grades according to the national standard. The fourth grade oil is only degummed and the third grade oil is deacidified. The fourth grade oil and the third grade oil can retain most of the flavor of the oil, and the smoke point is also much higher than that of the native oil. The fourth grade oil can reach 180 ℃ and the third grade oil is close to 200 ℃. After degumming and deacidification, all kinds of harmful substances in the oil can be reduced to a safe level.
