The Role of Lactic Acid in Cheesemaking
Lactic acid is a crucial component in the production of nearly all types of cheese. It is produced through the fermentation of lactose (milk sugar) by lactic acid bacteria (LAB). This process is controlled by cheesemakers using specific starter cultures of LAB, though some traditional artisanal methods rely on naturally occurring bacteria. The acid production is essential for several key functions in cheese manufacturing and aging:
- Coagulation: As LAB produce lactic acid, the pH of the milk drops. This increasing acidity causes the milk protein, casein, to clump together and form a solid curd, separating from the liquid whey.
- Moisture and Texture: The acidification promotes syneresis, the process where the curd shrinks and expels whey. The speed and extent of this process, controlled by factors like temperature and stirring, determine the final cheese's moisture content and texture.
- Inhibition of Pathogens: The acidic environment created by lactic acid inhibits the growth of unwanted spoilage organisms and pathogens, improving the cheese's safety and shelf life.
- Flavor Development: Lactic acid and other metabolic byproducts of LAB fermentation contribute significantly to the characteristic flavor and aroma of cheese. During aging, enzymes from the bacteria further break down proteins and fats into smaller compounds, creating more complex flavor profiles.
Cheeses with Prominent Lactic Acid Flavor and Properties
Fresh Cheeses
Fresh, unripened cheeses are typically made by acid coagulation alone, giving them a high moisture content and a distinctly fresh, tangy flavor profile. Examples include:
- Cottage Cheese: Often made with mesophilic starter cultures, which produce lactic acid to coagulate the milk proteins. The characteristic acidity gives it a fresh, slightly sour taste.
- Quark: A German acid-curd cheese where mesophilic LAB starters are used for fermentation, leading to milk coagulation and its typical mild, acidic flavor.
- Cream Cheese: Like quark, this is an acid-curd cheese that relies on lactic acid fermentation for its creamy texture and tangy taste.
- Mascarpone: While sometimes directly acidified with an acid like tartaric acid, its process is related to acid coagulation.
- Chevre: A soft goat's milk cheese where lactic acid is crucial for developing its specific flavor and texture.
Aged and Ripened Cheeses
In aged cheeses, the lactic acid undergoes further transformation during the ripening process, where other bacteria or molds contribute to flavor development.
- Cheddar: During the initial weeks of ripening, lactic acid concentration increases due to the metabolism of residual lactose. The subsequent aging process involves further changes by non-starter lactic acid bacteria, contributing to its sharp flavor.
- Parmesan: A study comparing different cheeses found Parmesan to have the highest lactic acid content among Parmesan, Mozzarella, Swiss, and Cheddar samples. This is a result of a long ripening process where LAB activity is extensive.
- Swiss-Type Cheeses (e.g., Emmental): The characteristic holes, or 'eyes,' are formed by Propionibacterium freudenreichii, which ferments lactic acid into propionic acid, acetic acid, and carbon dioxide.
- Mould-Ripened Cheeses (e.g., Camembert, Brie): Molds like Penicillium camemberti grow on the surface, metabolizing lactate and other compounds. This de-acidifies the cheese surface and affects the texture, ripening it from the outside in.
Comparison of Lactic Acid Content in Cheeses
| Cheese Type | Lactic Acid Production Method | Ripening/Aging | Characteristics & Lactic Acid Flavor |
|---|---|---|---|
| Cottage Cheese | Primarily acid coagulation by LAB. | None, consumed fresh. | High moisture, tangy, and fresh. The lactic acid is very prominent. |
| Cream Cheese | Primarily acid coagulation by LAB. | None, consumed fresh. | Smooth texture with a mild, fresh tanginess. |
| Quark | Primarily acid coagulation by LAB. | None, consumed fresh. | Soft, paste-like, with a clean and mildly acidic taste. |
| Cheddar | LAB fermentation, followed by ripening. | Aged for several months to a year or more. | Lactic acid content increases early on, developing a sharp, complex flavor through ripening. |
| Parmesan | Extensive LAB fermentation during long ripening. | Long-ripened, aged for a year or more. | High lactic acid content, which contributes to its sharp, complex, and savory flavor profile. |
| Swiss (Emmental) | Initial LAB fermentation, then secondary fermentation by Propionibacterium. | Aged at warmer temperatures for a period. | Lactic acid is converted to propionic acid, resulting in a nutty and sweet flavor with less overt acidity. |
| Brie/Camembert | Rennet and LAB for coagulation, mold for ripening. | Ripened with surface mold for weeks to months. | The mold metabolizes lactic acid on the surface, causing the interior to ripen and soften. |
The Role of LAB Beyond Acidification
The bacteria responsible for producing lactic acid are also important for several other functions that influence cheese quality and safety.
Flavor and Aroma Compounds
Beyond simple acidification, LAB can produce other compounds like diacetyl, which gives buttery flavors, and acetoin. In aged cheeses, dead LAB cells release enzymes that break down proteins and fats, contributing to the development of complex, desirable flavors during ripening.
Health-Promoting Effects
Cheese can offer health benefits due to its probiotic content derived from LAB. Live LAB strains present in cheese can improve digestive health and boost the immune system. The fermentation process can also increase the bioavailability of certain nutrients and produce bioactive compounds.
Biopreservation
LAB naturally produce antimicrobial substances called bacteriocins, which help to preserve the food. This biopreservation extends the cheese's shelf life and contributes to its microbiological safety, a crucial function in both artisanal and large-scale production.
Conclusion
Every type of cheese has lactic acid, though the way it is produced and its final concentration vary greatly. In fresh varieties like cottage cheese and quark, the characteristic tangy flavor comes directly from this acid, which is key for coagulation. For aged cheeses, from sharp cheddar to nutty Swiss, lactic acid is the starting point for a complex ripening process, transformed by other microbes into a spectrum of flavors and textures. The activity of lactic acid bacteria is fundamental to the entire cheese-making process, influencing everything from curd formation to the final sensory profile and nutritional benefits.
Learn more about the fundamentals of cheesemaking from The American Society for Microbiology.
What Cheese Has Lactic Acid: Key Takeaways
- Universal Presence: Lactic acid is found in virtually all cheese types, as it is a natural byproduct of the milk fermentation process by lactic acid bacteria (LAB).
- Fresh Cheese Tang: Fresh cheeses like cottage cheese, quark, and cream cheese have a pronounced tangy flavor because their curd is formed primarily through lactic acid coagulation.
- Aged Cheese Complexity: In aged cheeses, the lactic acid is further metabolized during ripening, contributing to a complex flavor profile, such as the sharp taste of Cheddar or the nutty notes of Swiss cheese.
- Ripening Effects: Lactic acid influences a cheese's texture, moisture content, and final pH, which in turn dictates how it ripens and what secondary microflora can develop.
- Health and Safety: The production of lactic acid inhibits the growth of harmful bacteria, acting as a natural preservative and enhancing food safety.
- Flavor Variety: The metabolism of lactic acid by secondary bacteria or molds, such as in Swiss or surface-ripened cheeses, is responsible for creating a wide range of unique flavors.
What Cheese Has Lactic Acid: FAQs
Q: Is lactic acid found in all cheeses?
A: Yes, lactic acid is found in almost all types of cheese. It is produced by lactic acid bacteria (LAB) that ferment lactose during the cheesemaking process, contributing to curd formation, texture, and flavor.
Q: What is the purpose of lactic acid in cheesemaking?
A: Lactic acid is critical for several functions: it causes the milk proteins to coagulate into solid curds, helps expel whey from the curds, inhibits the growth of harmful bacteria, and influences the final flavor and texture of the cheese.
Q: What cheeses have the strongest lactic acid flavor?
A: Fresh, unripened cheeses tend to have the most prominent lactic acid flavor. Examples include cottage cheese, quark, and chevre, where the tanginess from lactic acid is a key characteristic.
Q: Does lactic acid provide health benefits?
A: The lactic acid bacteria (LAB) used in cheesemaking are often probiotic and can offer health benefits, such as promoting gut health and boosting the immune system. Fermentation can also improve nutrient absorption and provide antioxidants.
Q: How does lactic acid affect aged cheeses?
A: In aged cheeses, lactic acid serves as an energy source for further microbial activity during ripening. For example, in Swiss cheese, it is converted into propionic acid, while in mold-ripened cheeses like Brie, it is metabolized by the surface molds.
Q: Is cheese with lactic acid good for lactose intolerance?
A: Yes, many cheeses contain very low amounts of lactose because it is fermented into lactic acid during production. Aged cheeses, in particular, have almost no residual lactose, making them suitable for many lactose-intolerant individuals.
Q: What is the difference between cheese made with lactic acid and rennet?
A: Some cheeses, especially fresh ones, rely solely on lactic acid to coagulate milk proteins. Most aged and hard cheeses use a combination of lactic acid and rennet. Rennet helps create a firmer curd, allowing for lower moisture and longer aging potential.
