Vegetable hydrogenated oil, hydrogenated palm oil, hydrogenated soybean oil, vegetable shortening, margarine, etc. There are many words such as yellow cream, cake oil and high-grade cream, all of which are disguised forms of trans fatty acids. Trans fatty acid is an unsaturated fatty acid produced in the process of hydrogenation modification of vegetable oil (modified oil is called hydrogenated oil). This processing can prevent the oil from deteriorating and change the flavor. Hydrogenated vegetable oil is the main food source of trans fatty acids. Vegetable oil, mainly unsaturated fatty acids, is hydrogenated and hardened under pressure and the action of catalysts such as nickel, and changes from liquid unsaturated fatty acids to solid or semi-solid saturated fatty acids. However, during the treatment, a part of unsaturated fatty acids in vegetable oil changed from cis-unsaturated fatty acids with natural framework to trans-unsaturated fatty acids.

Trans fatty acids fall into two categories:

1, one is the trans fatty acid produced by food after industrial processing, which has been proved by foreign research and domestic experiments to be harmful to human health;

2. The other is trans fatty acids naturally contained in dairy products and produced by bacterial fermentation. So far, there is no evidence to prove that these fatty acids are harmful to human health. The intake limit is mainly for trans fatty acids produced by industrial processing.