Cheddar cheese making (1895) (20577597926)

Cheese ripening, alternatively cheese maturation or affinage, is a process in

cheesemaking Cheesemaking (or caseiculture) is the craft of making cheese. The production of cheese, like many other food preservation processes, allows the nutritional and economic value of a food material, in this case milk, to be preserved in concentrat ...

. It is responsible for the distinct flavour of

cheese Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...

, and through the modification of "''ripening agents''", determines the features that define many different varieties of cheeses, such as taste, texture, and body. The process is "characterized by a series of complex physical, chemical and microbiological changes" that incorporates the agents of "

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

and enzymes of the

milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digestion, digest solid food. Immune factors and immune ...

, lactic culture,

rennet Rennet () is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease enzyme that curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a ...

lipases Lipase ( ) is a family of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually tr ...

, added moulds or

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...

s, and environmental contaminants". The majority of cheese is ripened, except for

fresh cheese There are many different types of cheese. Cheeses can be grouped or classified according to criteria such as length of fermentation, texture, methods of production, fat content, animal milk, and country or region of origin. The method most comm ...

History

Cheese ripening was not always the highly industrialised process it is today; in the past, cellars and caves were used to ripen cheeses instead of the current highly regulated process involving machinery and biochemistry. Some cheeses still are made using more historical methods, such as the blue cheese

Roquefort Roquefort is a sheep milk cheese from Southern France, and is one of the world's best known blue cheeses. Though similar cheeses are produced elsewhere, EU law dictates that only those cheeses aged in the natural Combalou caves of Roquefort-sur ...

, which is required to be ripened in designated caves in south-western

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

.Fox, Patrick. Cogan, Timothy. Guinee, Timothy. ''Fundamentals of Cheese Science''. p. 350. However, with the invention of

refrigeration The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...

in the 20th century, the process evolved considerably, and is much more efficient at producing a consistent quality of cheese, at a faster pace, and a lower cost (depending on the type of cheese).

Process

After the initial manufacturing process of the cheese is done, the cheese ripening process occurs. This process is especially important, since it defines the flavour and texture of the cheese, which differentiates the many varieties. Duration is dependent on the type of cheese and the desired quality, and typically ranges from "three weeks to two or more years".Fox, Patrick. ''Cheese: Chemistry, Physics and Microbiology''. p. 389. Ripening is influenced by a variety of factors, ranging from the

microflora Microbiota are the range of microorganisms that may be commensal, symbiotic, or pathogenic found in and on all multicellular organisms, including plants. Microbiota include bacteria, archaea, protists, fungi, and viruses, and have been found to ...

to the curd, and others. The enzymatic process is the most crucial process for all cheeses, although

plays a role in many varieties. The most important agents in this process include the following elements: *

Rennet Rennet () is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease enzyme that curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a ...

, or a substitute for rennet * starter

and associated enzymes * milk

enzymes Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

* second starter bacteria and associated enzymes * non-starter bacteria Each of these factors affects the cheese-ripening process differently, and has been the subject of much research. It is important for manufacturers to understand how each of these elements work, so that they are able to maintain the quality of the cheese while producing the cheese at an acceptable investment of time and cost. These agents contribute to the three primary reactions that define cheese ripening:

glycolysis Glycolysis is the metabolic pathway that converts glucose () into pyruvate (). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH ...

proteolysis Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called protease ...

, and

lipolysis Lipolysis is the metabolic pathway through which lipid triglycerides are hydrolyzed into a glycerol and free fatty acids. It is used to mobilize stored energy during fasting or exercise, and usually occurs in fat adipocytes. The most important ...

. By taking the cheese through a series of maturation stages where temperature and relative humidity are carefully controlled, the cheese maker allows the surface mould to grow and the mould ripening of the cheese by fungi to occur. Mould-ripened cheeses ripen faster than hard cheeses, in weeks as opposed to the typical months or even years. This is because the

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

used are more biochemically active than the starter bacteria. Where the ripening occurs is largely dependent on the type of cheese: some cheeses are surface-ripened by moulds, such as Camembert and

Brie Brie (; ) is a soft cow's-milk cheese named after Brie, the French region from which it originated (roughly corresponding to the modern ''département'' of Seine-et-Marne). It is pale in color with a slight grayish tinge under a rind of white m ...

; and some are ripened internally, such as

Stilton Stilton is a village and civil parish in Cambridgeshire, England, about north of Huntingdon in Huntingdonshire, which is a non-metropolitan district of Cambridgeshire as well as a historic county of England. History There is evidence of Neo ...

. Surface ripening of some cheeses, such as

Saint-Nectaire Saint-Nectaire is a French cheese made in the Auvergne region of central France. The cheese has been made in Auvergne since at least the 17th century. History Up until the 17th century, the Saint-Nectaire cheese was farmstead, and mostly made ...

cheese, may also be influenced by

s which contribute flavour and coat texture. Others are allowed by the cheesemaker to develop bacterial surface growths which give characteristic colours and appearances. The growth of ''Brevibacterium linens'', for example, creates an orange coat to cheeses. In contrast to

cheddaring The manufacture of Cheddar cheese includes the process of ''cheddaring'', which makes this cheese unique. Cheddar cheese is named for the village of Cheddar in Somerset in South West England where it was originally manufactured. The manufacturin ...

, making cheeses like

Camembert Camembert (, also , ) is a moist, soft, creamy, surface-ripened cow's milk cheese. It was first made in the late 18th century in Camembert, Normandy, in northwest France. It is sometimes compared in look and taste to brie cheese, albeit with ...

requires a more gentle treatment of the curd. It is carefully transferred to cheese hoops and the whey is allowed to drain from the curd by gravity, generally overnight. The cheese curds are then removed from the hoops to be brined by immersion in a saturated salt solution. This is because the amount of

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

has a large effect on the rate of

in the cheese, stopping the bacteria from growing. If white-mould spores have not been added to the cheese milk, the cheese maker applies them to the cheese either by spraying the cheese with a suspension of mould

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s in water, or by immersing the cheese in a bath containing spores of, e.g., ''Penicillium candida''.

Effect on features

Eyes

The round holes that are a characteristic feature of

Swiss-type cheese Swiss-type cheeses, also known as Alpine cheeses, are a group of hard or semi-hard cheeses with a distinct character, whose origins lie in the Alps of Europe, although they are now eaten and imitated in most cheesemaking parts of the world. Their ...

P.L.H. McSweeney and P.R Fox; ''Metabolism of Residual Lactose and of Lactate and Citrate'', in: Fox, p. 366 (e.g.

Emmentaler cheese Emmental, Emmentaler, or Emmenthal is a yellow, medium-hard cheese that originated in the area around Emmental, in the canton of Bern in Switzerland. It is classified as a Swiss-type or Alpine cheese. Emmental was first mentioned in written reco ...

) and some Dutch-type cheeses are called "eyes". They are bubbles of

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

that is produced by

in the cheese. In Swiss-type cheeses, the eyes form as a result of the activity of propionic acid

(''

propionibacteria ''Propionibacterium'' is a gram-positive, anaerobic, rod-shaped genus of bacteria named for their unique metabolism: They are able to synthesize propionic acid by using unusual transcarboxylase enzymes. Its members are primarily facultative par ...

''), notably ''

Propionibacterium freudenreichii ''Propionibacterium freudenreichii'' is a gram-positive, non-motile bacterium that plays an important role in the creation of Emmental cheese, and to some extent, Jarlsberg cheese, Leerdammer and Maasdam cheese. Its concentration in Swiss-ty ...

'' subsp. ''shermanii''.P.L.H. McSweeney, ''Biochemistry of Cheese Ripening: Introduction and Overview'', in: Fox, p. 349 In Dutch-type cheeses, the CO₂ that forms the eyes results from the metabolisation of

citrate Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in t ...

by citrate-positive ("Cit+") strains of

lactococci ''Lactococcus'' is a genus of lactic acid bacteria that were formerly included in the genus ''Streptococcus'' Group N1. They are known as homofermenters meaning that they produce a single product, lactic acid in this case, as the major or only pr ...

.P.L.H. McSweeney and P.R Fox; ''Metabolism of Residual Lactose and of Lactate and Citrate'', in: Fox, p. 367

Taste

The process of cheese ripening affects the taste of the final product. If the product is not ripened, the resulting cheese is tasteless, and so all cheese is ripened except for fresh cheeses. Different factors define taste in cheese, including

casein Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of ...

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers spec ...

brine Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...

and many other elements. Brine, for example, mixes with

saliva Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be ...

, delivering the flavour of the cheese to the

taste buds Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the che ...

and determining the cheese's moistness. Many of these elements are specific to the type of cheese. For instance,

proline Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the prot ...

is more abundant in

Emmental The Emmental ( en, Emme Valley) is a valley in west-central Switzerland, forming part of the canton of Bern. It is a hilly landscape comprising the basins of the rivers Emme and Ilfis. The region is mostly devoted to farming, particularly dai ...

than in any other type of cheese and gives the cheese its much

sweet Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketones ...

er taste.Fox, Patrick. ''Cheese: Chemistry, Physics and Microbiology''. p. 418.

Footnotes

References

* * {{DEFAULTSORT:Cheese Ripening Cheese Fermentation in food processing