Monosodium glutamate (MSG) is a food additive used to add the taste umami to dishes. It is created through the combination of sodium and glutamate, and is found in many processed foods but can also be used at home. This additive is most common in Asian dishes.
Created by combining sodium with glutamate, MSG is a white, crystalline solid, much like salt. It is sometimes made through extracting glutamate from foods, such as seaweed, that are rich in protein. Another, more common method of manufacture is though fermentation, which produces greater amounts more quickly than does extraction.
Glutamate, an amino acid that is found naturally in many foods that contain protein, is the main active component of monosodium glutamate. Although glutamate is found in many foods, it is often bound to other amino acids in protein molecules and, therefore, does not enhance flavor. Less often, glutamate is found in foods in its free, unbound form. Foods such as tomatoes and mushrooms have unbound glutamate molecules, and because of this, these foods are often used to enhance flavors.
When it is added to savory food, MSG adds a meaty or brothy taste. In Japan this flavor is known as umami, and is considered the fifth taste, in addition to sweet, sour, salty and bitter. It is also a way to enhance the existing flavors of food.
Only certain foods benefit from the addition of monosodium glutamate. It may enhance or improve the taste of salty and sour flavors, but produces little to no improvement in sweet or bitter flavors. For this reason, it is generally only added to soups, meats, gravy, and other savory foods. MSG is self-limiting, which means that after a certain amount has been added, no extra flavor can be produced by adding more. Typically, half a teaspoon of MSG is used to flavor one pound of meat.
Although it is usually found in processed foods, monosodium glutamate may also be purchased for use in home cooking. It may be added to anything from chili to eggs to guacamole. Only a very small amount should be used, adding only a pinch or a dash at a time. Some avoid using MSG in foods that have naturally high levels of glutamate, such as tomato paste and parmesan cheese. Also, the amount of salt in the dish should be reduced when MSG is added.
Although the US Food and Drug Administration (FDA) says that monosodium glutamate is safe for consumption, some individuals are sensitive to it. Symptoms such as flushing and sweating, nausea, numbness, weakness and heart palpitations have been reported. Headaches have also been known to occur, and some people with severe asthma find that their symptoms worsen after consuming MSG.