In the chemical structure of oils and fats, the hydrogen atoms of fatty acids are distributed on the same side of the unsaturated bond, which is called cis fatty acid; on the contrary, the hydrogen atoms are distributed on both sides of the unsaturated bond, which is called trans fatty acid. The vast majority of fatty acids in natural vegetable oils are cis-fatty acids. Trans-fatty acids are rarely found in natural foods. How does it appear in daily foods and damage human health?

　　Can not help but pay attention to a special fat processing method-hydrogenation, vegetable oil is widely used in food processing, although vegetable oil (mainly unsaturated fatty acids) in health benefits significantly exceeds animal oil (mainly saturated fatty acids), but processing In terms of performance, the shortcomings of vegetable oils are that they are easily oxidized (have a "hala flavor"), are not crispy, and are easily destroyed during frying, etc. In order to solve these problems, "hydrogenation" is usually required, that is, opening the double bond of unsaturated fatty acids and Adding a hydrogen atom makes it a single bond, that is, it turns unsaturated fatty acids into saturated fatty acids. This hydrogenated oil (mainly saturated fatty acids) has excellent processing properties. For example, if the ordinary vegetable oil is used to make instant noodles (or biscuits), the shelf life is about 1 to 3 months, and the shelf life of hydrogenated oil is up to 3 years; Hydrogenated oil can be used to make shortcakes, pastry bread, etc.; hydrogenated oil can be used to simulate cream to make birthday cakes; hydrogenated fried chips, twists, etc. can keep the fat clear and not turbid for a long time... because of this, hydrogenation in recent years Oil is widely used. In addition to the above-mentioned foods, hydrogenated oil is also used to process fried snacks and coffee mates. However, hydrogenated oil contains a large amount of trans fatty acids, which is unhealthy for health.

　　 "Dietary Guidelines for Chinese Residents 2007" pointed out that high intake of trans fatty acids can lead to hyperlipidemia and increase the risk of arteriosclerosis; trans fatty acids interfere with the metabolism of essential fatty acids and can affect children’s growth and development . In fact, with the understanding of the dangers of trans fatty acids, developed countries such as Europe and the United States have begun to restrict trans fatty acids. For example, the New York Health Commission of the United States passed a bill in December 2006 that prohibits the use of non-use in all restaurants and cake shops in New York City. Trans fatty acids are good for human health.

　　In recent years, a large number of domestically imported and used hydrogenated oils (including trans fatty acids) have been widely used in the food processing industry and catering industry, and consumers still lack awareness, let alone vigilance, or even Not included in the national health standards, its harm is worrying.