Monosodium glutamate, MSG for short, has a bad rep. It is a natural organic chemical that exists naturally in all fruits, vegetables and meats. You consume it daily. Some foods are rich in MSG, such as Roquefort and Parmesan cheeses, soy sauce and nuts; all meats, poultry and seafood contain a lot. Vegetables also contain plenty, with champion amounts in peas and corn. Milk and dairy products are MSG rich, and even mothers’ milk contains a modest amount.
Some of today’s MSG is still produced from seaweed; others are extracted through a fermentation process of molasses.
MSG does not change the flavor of foods (like spices do) even the slightest. It only changes your perception of the flavor by chemically affecting your taste buds, like the bite from a hot chili does.
The way MSG enhances food flavors is almost like magic—it markedly accentuates and sharpens flavors with a pleasant mouthfeel, the sensation of satisfaction, richness and fullness. It also reduces perception of the sharp, unpleasant edge of onion taste; the earthiness of potatoes; and the bitterness of some vegetables. In addition, it generates an agreeable meaty flavor. A small amount of MSG creates the perception of saltiness in foods, so much so that processors with a tiny amount of additional MSG can reduce salt by up to 30 percent and not lose the satisfying salty flavor.
Many cooks and chefs keep MSG on their shelves next to their salt shaker. If you decide to use it, add ½ a teaspoon per 4 to 6 servings of soups, stews and sauces. You can add MSG during or near the end of the cooking process.(Excerpt from my book What Recipes Don't Tell You)