Understanding Glutamate: Bound vs. Free
Glutamate is an amino acid, one of the building blocks of protein. It exists in food in two forms: bound and free. Bound glutamate is linked to other amino acids as part of a larger protein molecule, while free glutamate is not. Only free glutamate can activate the umami taste receptors on your tongue, giving food that deep, savory flavor.
Processes like aging, ripening, and fermentation break down proteins, releasing more free glutamate and boosting the umami taste. This is why aged Parmesan has a more intense flavor than a mild cheese.
Foods Naturally High in Free Glutamate
Many common, whole foods are excellent natural sources of free glutamate. Incorporating these ingredients is a simple way to boost umami without relying on processed additives.
Aged and Fermented Foods
Fermentation and aging significantly increase free glutamate content.
- Aged Cheeses: Parmesan is particularly high, with others like Swiss and cheddar also offering significant amounts.
- Fermented Sauces: Soy sauce, miso paste, and fish sauce get their rich flavor from high levels of free glutamate.
- Cured Meats: Cured ham and salami contain more free glutamate than fresh meats due to aging and curing.
Vegetables and Fruits
Ripening increases free glutamate in some produce.
- Ripe Tomatoes: Deep red tomatoes have a higher free glutamate content than pale ones.
- Mushrooms: Dried mushrooms are especially rich, containing guanylate which amplifies umami.
- Peas and Broccoli: These contain notable levels of free glutamate.
Animal and Seafood Sources
Meat and seafood contribute glutamate, with long cooking times increasing free glutamate.
- Bone Broths and Stocks: Slow-cooking releases a high concentration of free glutamate.
- Seafood: Anchovies, scallops, and shrimp are rich sources.
- Meat and Eggs: Eggs are a good source, and cooking meat longer increases free glutamate.
Natural vs. Added Free Glutamate
Natural free glutamate and added MSG are chemically and metabolically identical.
Table: Natural vs. Added Glutamate
| Feature | Natural Free Glutamate | Added MSG |
|---|---|---|
| Source | Produced naturally in foods through ripening, aging, and fermentation. | Commercially produced via fermentation of sugars or starches. |
| Context | Found with other nutrients and flavors in whole foods. | An isolated additive for flavor enhancement. |
| Metabolism | Metabolized identically to added MSG. | Metabolized identically to natural free glutamate. |
| Concentration | Varies widely by food, ripeness, and preparation. | Provides consistent and controlled umami addition. |
How to Use Free Glutamate in Your Cooking
Boost umami by using ingredients and techniques that increase free glutamate:
- Use Concentrated Ingredients: Add soy sauce, fish sauce, or miso for an instant boost.
- Cook for Longer: Slow-cooking stocks and stews releases more free glutamate.
- Use Ripened Vegetables: Choose ripe tomatoes for richer flavor.
- Incorporate Aged Foods: Sprinkle Parmesan or add cured ham.
- Dry Your Ingredients: Dried mushrooms offer concentrated flavor.
What about MSG?
MSG is the sodium salt of glutamate, made by fermenting starch or sugar. Its glutamate is chemically indistinguishable from naturally occurring glutamate. While MSG is a pure source, natural foods contain it within a complex profile. There's no scientific evidence of a widespread MSG allergy, but those sensitive to it may also react to naturally glutamate-rich foods. For more details, see the article "Glutamates: Natural And Safe To Consume".
Conclusion
Free glutamate creates the umami taste and is found naturally in aged, fermented, and ripe foods like Parmesan, soy sauce, tomatoes, and mushrooms. These ingredients enhance savory flavor in cooking. Regardless of whether it comes from MSG or a slow-simmered broth, the glutamate molecule is the same, offering a pathway to mastering savory flavors.
