Tyramine is a biological amine that occurs naturally in plants and animals. It can also be formed from tyrosine, which is found in many foods and is gradually reduced as food begins to ferment. Tyramine, in its molecular structure, contains nitrogen, which comes from ammonia. Tyramine can be found in cheese, yeast, meat, fish, beans and other foods, especially after fermentation or aging treatment of food, tyramine content will be relatively high. Generally, fresh food does not contain or contains a very small amount of tyramine, in addition, protein decomposition, tyramine will also appear, such as tofu, soy sauce, soy milk and other soy products.
Modern food preparation processes can largely reduce tyramine in foods, except for some cheeses and sauces. We can measure tyramine content by liquid chromatography. After tyramine is absorbed by human body, intestinal monoamine oxidase is metabolized. It is not only the substrate of type I monoamine oxidase, but also the substrate of DA transporter, vesicular monoamine transporter, NE transporter and trace amine-associated receptor 1.