Emmentaler and Swiss-Style Cheese

Cheese is among the most ancient manufactured foods. More than a thousand cheese varieties are known throughout the world. This astounding diversity stems from a number of factors, including the type of milk used (cow, ewe, goat, caribou, buffalo, yak), the manufacturing process and local preferences. Some prestigious cheeses are labeled with an "Appellation d'Origine Contrôlée", a quality marking that certifies that a product has been developed in a given region following a stringent manufacturing process. Emmentaler cheese is made from cow's milk and traces its origins to theEmme Valley in Switzerland, hence its name (Tal is the German word for "valley").

Emmentaler and other Swiss-style cheeses are characterized by large holes, commonly known as cheese eyes. These cavities are in fact carbon dioxide bubbles that form and remain trapped in the cheese as a result of specific bacteria action over the course of the aging process. In addition to this unique aspect, Emmentaler and Swiss-style cheese owe their originality and versatility to their outstanding melting properties. Known as the ingredient of choice for "au gratin" dishes, these cheeses can be relied on to enhance any foods with their distinctive hazelnut taste and desirable baking qualities.

The Emmentaler "Appellation d'Origine Contrôlée" standard requires that cheese wheels be between 70cm and 1 m in diameter, weigh between 60kg and 130kg, have a minimal fat content of 45% (expressed on a dry basis, ie. M.F./dry matter x 100); the dry natural rind must be washed and brushed, have an ochre or yellow colour; the interior must be cooked and pressed, be ivory to pale yellow in colour, and contain holes the size of a cherry to a nut. The holes or "eyes" must be round, well-defined and distributed evenly throughout. The absence of grooves (fallen eyes) is indicative of good quality. Aging may take place over a period varying from 5 months to a year. The cheese has a mellow and sweet flavour that may intensify with the aging process.

Cooked and pressed cheeses such as Emmentaler and Swiss-style cheese are classified as firm, and are produced by heating the whey for at least an hour to firm it up and obtain a compact cheese after the pressing process.

This particular method of production combines two successive fermentation processes. Lactic fermentation caused by Streptococcus thermophilus, Lactobacillus delbrueckii (subsp bulgaricus and subsp lactis) and Lactobacillus helveticus occurs over the 24-hour period following the renneting process. As a result, the pH of the whey is lowered to approximately 5.4-5.5 at the sixth hour of the pressing phase, with the cheese later reaching a final pH level of 5.1-5.3. This step plays an important part in the preservation and the quality of cooked and pressed cheeses as it inhibits the development of microorganisms responsible for spoilage. The lactic fermentation is followed by the propionic fermentation, which is caused by Propionibacterium freudenreichii subsp shermanii and occurs in the aging cellar (warm cellar between 15 and 24EC). It is during this last fermentation that these cheeses normally acquire the eyes (holes) that characterize them. If the aging takes place at too low a temperature (12EC), as is the case with Beaufort cheese, the "eyes" will not develop. Indeed, a proper lactic fermentation process need occur to the extent that it affects the propionic fermentation.

As in the case of Emmentaler, Gruyere originates from the Swiss country. The characteristics of its "eyes" differentiate it from its cousin: its eyes are much smaller, fewer in number and in certain cases are even absent. A number of Swiss-style cheeses have been identified based on the area where they are produced:

• Raclette, Beaufort, Comté is made on French soil;
• Jarlsberg is from Norway;
• Maasdam is from Holland;
• Fontina is from Italy;
• All the other cheeses produced with the same ferments as those required for the production of Emmentaler but which are not produced by the countries operating under the AOC (appellation d'origine contrôlée).

These generic Swiss types are generally made in industrial quantities on a continuous basis. They go through a shorter aging period and are not encased in rind.

Canadian law states that Swiss-style cheese must contain a maximum moisture content of 40.0 % and a minimal milk fat content of 27.0 %. These values are expressed on a wet basis.

In terms of microbiological quality, it is unlawful to sell cheese made from pasteurized raw material if the cheese contains more than 100 Escherichia coliper gram or 100 Staphylococcus aureus per gram. In Canada, cheese with an aging period of less than 2 months must be made from pasteurized milk if it is to be sold.

There are numerous assessment criteria for Emmentaler and Swiss-style cheeses. Easy to use, these select dairy ingredients add to the flavour of cooked meals, to their nutritive value (100 g of Emmentaler provide as much protein as 250 g of meat), to their cost effectiveness and their utility. Depending on the application, these cheeses are added to foods prior to cooking in order to increase viscosity, improve texture or colour, or bind other added ingredients. Their most desirable functional properties include:

• Melt: When exposed to heat, the cheese starts to melt as soon as its structure can no longer support its own weight and so loses its shape and flows under the influence of gravity. The melting property can be assessed by measuring the spreading tension. The ratio between the areas of the melted cheese and that of the initial piece of cheese is calculated. Emmentaler has excellent melting properties, which vary with the composition of the cheese, its pH, the degree of casein hydrolysis and how the cheese is melted (microwave or thermal heat).
• Stretch: The stretching characteristics of cheese depend on the degree of intact casein, pH and the proportion of calcium phosphate that has been dissociated from the casein micelle. At a pH of around 5.2, the right level is attained and the calcium phosphate, which acts to bind the micelle, allows the cheese to stretch. The pH of Emmentaler and Swiss-style is in this ideal zone (5.1-5.3). The length of their strands varies between 80and 300 mm.
• Browning: While cooking, the cheese surface browns because of the heat-induced interaction between sugars and amino-acids. During cheese production, lactose (milk sugar) metabolizes into galactose and glucose, while casein (cheese protein) is subjected to enzymatic action that breaks down its structure and gradually releases amino-acids. Residual galactose content and the intensity of the secondary proteolysis (during the aging process) have been cited as significant factors involved in the browning of cheese. Hence, the Maillard reaction is responsible for the colour of cheese au-gratin and the creation of particular aromas that add to the appeal of cooked meals.

For more information on cheese, please visit the University of Guelph's Dairy Science and Technology Web site.