The following points highlight the three categories of cheese. The categories are: 1. Lactic Acid/Rennin Based Cheese 2. Fat Content Based Cheese 3. Physical State of Structure Based Cheese.
Category # 1. Lactic Acid/Rennin Based Cheese:
Cheese are divided into two large groups depending upon whether the curd is formed by the action of lactic acid or it is developed by the action of rennet (rennin) enzyme.
These groups are:
1. Acid-curd cheese or cottage cheese and
2. Rennel-curd cheese.
1. Acid-curd cheese or Cottage cheese:
To prepare this cheese the milk is allowed to sour spontaneously or, as a result of inoculation with ‘starter’, Streptococcus lactis or lactobacilli are inoculated to grow in it until they produce sufficient acid to allow the milk curdle.
The curd is separated from the whey, some salt is added to it, and formed into balls or cakes. The cheese is ready for consumption now. Such cheese cannot be kept for very long periods because moulds and yeasts begin to develop which soon spoil the flavour and render the cheese unfit for use.
2. Rennet-curd cheese:
A great variety of cheese is produced by the action of rennet (rennin) enzyme.
The rennet-curd cheese may be divided into two further groups:
(i) Soft rennet-curd cheese and
(ii) Hard rennet-curd cheese.
(i) Soft Rennet-curd Cheese (50%-80% water):
These have generally poor keeping qualities and a short ripening period. Those which are prepared by bacterial action are known as Limburger and Liederkranz and their varieties; those prepared by the action of moulds we know as Camembert and Brie.
(a) Limburger Cheese:
In Limburger relatively little salt is added to the curd and the cheese in handled frequently so that bacterial growth occurs on the surface. These bacteria destroy the acid and permit the partial putrefaction and decomposition of casein, giving the characteristic flavour.
(b) Lienderkranz Cheese:
It is very similar to limburger cheese except that considerable salt is added to the curd. This promotes a different flora of organisms on the surface of the cheese, and thus a different flavour is obtained.
(c) Camembert Cheese:
The curd retains a much larger proportion of the whey. The cheese is moulded into small cakes and placed in a curing room, the temperature of which is usually not very low. Moulds soon cover the surface of the cheese, Geotrichum candidum developing first, and later various species of Penicillium, particularly, P. camembertii. These moulds are capable of utilizing organic acids as food.
The acidity of the cheese is thus gradually reduced, and at the same time the moulds secrete proteolytic enzymes which gradually diffuse toward the interior of the cheese. The mycelium, however, ordinarily does not penetrate the cheese to any considerable distance.
When the proteolysis occasioned by this mould development has penetrated to the centre of the cheese, ripening is completed. It is believed that the proteolytic changes in the texture of this cheese ripening are due to the Penicillium, while the characteristic flavour has been ascribed to Geotrichum.
(ii) Hard Rennet-curd Cheese (less than 40% water):
The hard rennet-curd cheese have a long ripening period, generally with good looking qualities and, in fact, they may be preserved for years. American cheese (cheddar cheese) and Swiss cheese examplify those hard rennet-curd cheese in which bacteria are primarily involved in the curing processes.
Roquefort, Lowa blue cheese are the examples of those hard rennet-curd cheese in which the ripening process is carried out primarily by moulds.
(a) American Cheese (Cheddar Cheese):
For the preparation of it, the curd is precipitated, after acidification, with rennet. The whey is drained off the curd but a little amount is retained. The curd is salted and then the excess whey is pressed out of it by pressing the curd in a cheese press.
The cheese is stored and gradually develops a flavour due to slow bacterial action. Its flavour depends somewhat on its age. The older the cheese, the greater the degree of decomposition of protein to amino acids, and the sharper the flavour.
(b) Swiss Cheese:
For the preparation of Swiss cheese, fresh sweet milk is taken and heated in a large kettle to 56°C (130°F). At this temperature, rennet, a starter culture containing thermophilic organisms (Streptococcus thermophilus), some thermophilic lactobacilli, and some propionic acid bacteria are added.
It is the latter bacteria which give Swiss cheese its characteristic flavour and the gas produced causes holes. Swiss cheese is graded on the number of holes, their size, and whether or not the inside is shiny.
(c) Roquefort Cheese:
Roquefort cheese is probably the best known cheese made from sheep’s milk. However, other milk is frequently used for the preparation of this cheese. The cut surface of this cheese shows a characteristic greenish blue mottling due to the presence of a specific mould, Penicillium roquefortii.
It has been found that the characteristic aroma and flavour of roquefort cheese is due to the production of the compound methylamylketone from the milk fat.
Apparently, one reason for the superiority of sheep’s milk in making the blue cheese (Roquefort cheese) is that the fat globules are much smaller than those of cow’s milk. The smaller the globules in milk of a definite fat content, the greater the opportunity for the fat to be attacked by the mould enzymes.
Category # 2. Fat Content Based Cheese:
Cheese can be of two distinct types depending upon the fat content present in it.
1. High-fat cheese and
2. Low fat Cheese.
1. High-fat Cheese:
Curd with additional cream so as to reach fat content to the level of 60% and above.
2. Low-fat Cheese:
Curd without additional cream resulting into fat content to be less than 60%.
Category # 3. Physical State of Structure Based Cheese:
On the basis of physical state of structure, the cheese can be easily grouped into three categories.
These categories are:
1. Soft Cheese,
2. Semi-hard cheese, and
3. Hard Cheese.
1. Soft Cheese:
This category of cheese includes ripened and un-ripened types that include the following three subtypes:
(i) Un-ripened cheese (Cottage cheese, Gorgenzola cheese, Stilton cheese),
(ii) Bacteria-ripened cheese (Limburger cheese) and
(iii) Mould-ripened cheese (Camembert cheese, Brie cheese).
2. Semi-hard Cheese:
This category includes only ripened type of cheese which is neither soft nor hard. The ripening is done by both bacteria and moulds.
The following are different types and subtypes of semi-hard cheese:
(i) Mould-ripened cheese (Gorgenzola cheese, Roquefort cheese, Stilton cheese’) and
(ii) Bacteria- ripened cheese (Brick cheese, Muenster cheese).
3. Hard Cheese:
These are hard texture cheese and include only ripened types. The hard cheese are all bacteria-ripened only.
These are following types and subtypes of hard cheese:
(i) Cheese with gas holes (Swiss cheese, Parmeson cheese) and
(ii) Cheese without gas holes: Cheddar cheese, Edam cheese.