Understanding Glutamate in Cheese
Glutamate is a naturally occurring amino acid that is a major component of protein in many foods, including milk. The savory fifth taste, known as umami, is driven by the presence of free glutamate, which is not bound to other amino acids. The question of whether and how much cheese increases glutamate is directly tied to the cheesemaking and aging process.
The Fermentation and Aging Process
The journey from milk to a rich, umami-laden cheese is a fascinating biological process. During fermentation, lactic acid bacteria break down the lactose in milk. Crucially, as the cheese matures, a process called proteolysis occurs. Enzymes, either naturally present in the milk or from starter cultures, systematically break down the milk's proteins (casein) into smaller peptides and individual amino acids, including free glutamate.
- Free Amino Acids: Unlike proteins, which have no taste, these free amino acids each have their own unique flavor profile. Glutamate is the primary driver of the umami taste.
- Aging Time: The length of the aging period is the most significant factor. The longer a cheese is aged, the more extensive the proteolysis and the higher the concentration of free glutamate.
- Moisture Content: As cheese ages, it loses moisture, which further concentrates the free amino acids, enhancing the umami.
This explains why a fresh, soft cheese like mozzarella has a mild, creamy taste, while a hard, aged Parmesan offers a much more intense, savory flavor. The small white crystals found in aged cheeses like Parmigiano-Reggiano are not glutamate, but rather crystallized amino acids such as valine, leucine, and isoleucine.
High-Glutamate Cheeses and Umami Power
The glutamate content varies dramatically across different types of cheese. The following list highlights some of the richest sources:
- Parmesan: Often cited as one of the highest natural sources of glutamate, Parmesan contains approximately 1,680 mg per 100g. Its long aging period and low moisture contribute to its exceptional umami depth.
- Roquefort: This blue-veined sheep's milk cheese also has a very high glutamate content, clocking in at around 1,280 mg per 100g.
- Aged Cheddar: While less concentrated than Parmesan, mature cheddar aged for over 14 months can still have a rich umami flavor profile from its free amino acids. One study notes levels around 180 mg per 100g, significantly higher than fresh varieties.
Natural vs. Added Glutamate: The MSG Distinction
It is important to differentiate between naturally occurring glutamate and the food additive monosodium glutamate (MSG).
- Naturally Occurring: The glutamate in cheese is released naturally as a result of the aging process, bound within the protein structure of the milk.
- Added MSG: Monosodium glutamate is the sodium salt of glutamic acid, produced via a fermentation process and added to foods to enhance flavor. The human body, however, processes both forms in the same way.
This is a key takeaway for anyone concerned about MSG. The glutamate in a cheese-and-tomato sauce is indistinguishable to the body from the glutamate added as MSG to a packaged soup. The real difference is the processing and source, not the metabolic pathway.
Comparative Glutamate Content in Common Foods
| Food Item | Free Glutamate Content (mg/100g) | Notes |
|---|---|---|
| Parmesan Cheese | 1680 | A peak example of a naturally high glutamate food. |
| Soy Sauce | Up to 1700 | Fermented sauce, very high in umami. |
| Roquefort Cheese | 1280 | Blue cheese with concentrated flavor. |
| Dried Shiitake Mushrooms | 1060 | Another natural umami powerhouse. |
| Walnuts | 658 | Nuts can be a surprising source. |
| Cured Ham | 340 | Curing and processing increases content. |
| Fresh Tomatoes | Up to 250 | A classic umami source that enhances other flavors. |
| Cheddar Cheese | 180 | Contains less glutamate than aged Italian varieties. |
| Fresh Mozzarella | Minimal | A young, fresh cheese with low glutamate content. |
| Cod | 9 | Low on the glutamate scale compared to umami-rich foods. |
Health Considerations and Umami Satisfaction
For the vast majority of the population, consuming naturally high-glutamate foods like cheese is safe and adds depth to their diet. However, some people report sensitivities to high doses of free glutamate, sometimes associated with symptoms like headaches or flushing. It is worth noting that these reactions are often linked to processed foods containing added MSG, which are often high in sodium and other additives that could be the true cause of the symptoms.
The umami taste provided by glutamate also plays an important role in satiety. The savory richness of aged cheese can make a small portion feel more satisfying, potentially aiding in portion control.
Conclusion
To answer the question, yes, cheese does increase glutamate, but this is a natural consequence of its aging and fermentation process, not a cause for concern for most people. The levels are highest in hard, aged varieties like Parmesan and Roquefort, where the umami flavor is most concentrated. Understanding the origin of this glutamate helps to clarify its role in our diet and dispels common misconceptions related to added MSG. For those seeking a delicious source of natural umami, aged cheese is a flavorful and satisfying choice.
Learn more about the flavor science of umami and glutamate by exploring the International Food Information Council (IFIC) resources.
