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Cheese and Serra da Estrela cheese

Atualizado: 12 de fev. de 2020

What do you know about the history of cheese?


Cheese is one of the most consumed dairy products in the world and World Cheese Day is celebrated on January 20th #CheeseLoversDay.


According to legend, the cheese was discovered by one of the sons of Apollo, Aristeu, King of Arcadia.

It is admitted that it was invented before the butter. The Assyrians, the Chaldeans, the Egyptians, and lastly, the Greeks and Romans, enjoyed the cheese, from which they made innumerable varieties, and whose virtues they knew since they used it to feed soldiers and athletes.



The elaboration of this food, so much appreciated by us, is based on three fundamental discoveries, which have remained forever:

  • The first one: milk has been obtaind for over 10,000 years, and used by humans as a component of their diet.

  • Second Discovery: the influence of temperature. In the cellars, due to fire and heat, the milk curdled rapidly and when the milk curdled and solidified, a liquid dripped and the curd became more consistent. This process was later accelerated by placing the curdled milk in a wicker basket or other container provided with holes to let the "whey" run through. This produces a consistent white paste (curd, which is still produced by the same process today).

  • The last and the third one: rennet, a digestive enzyme that is extracted from the goat's stomach.

About 400 cheese species have been numbered around the world and over the centuries: each variety has gradually gained its own reputation and completes every meal nicely.

The authenticity of cheeses is of great importance, since in many countries there is a regulation on their manufacture and their certificates of origin, such as Portugal.




7 facts about cheese


  1. Cheese was created over 4,000 years ago-by accident.

  2. Some cheeses are illegal in the United States.

  3. Cheese caves are a real thing.

  4. Mice don’t like cheese, like us they prefer sweet food!

  5. Lactose-intolerant people can eat cheese.

  6. There is a reason certain cheese names are capitalized: they are country associated.

  7. Curd sizes yield different types of cheese.



Cheese Preservation


The ideal temperature for preserving cheese varies depending on the type of cheese. Hard cheese must be kept between 8 and 12 °C, while soft cheese is best preserved at lower temperatures. between 4 and 8 °C.


The shelf-life of cheeses varies by their type:

  • Smaller cheeses, poorly ripened cheeses, soft cheeses and low-fat cheeses have the shortest conversion time. These types of cheese should not be kept cold for more than 15 or 20 days.

  • In the case of buttered cheeses we should eat them as soon as possible and in no case should we store them for more than one month.

  • Pressed goat cheese, for example 1 kg, can be stored between 1 and 2 months and a little longer if longer.

  • Paste sheep's cheeses are the ones that can be stored the longest, 1 kg can be stored for months, and the harder the cheese paste is and the more fat the milk has, the better it will be kept.



Curiosity


Cheese is a national reference for French. Since 2001, March 29th is considered “the fromage day” in France. During World War II, it was cited by General de Gaulle as a country symbol: “Un pays qui produit plus de 300 sortes de fromages ne peut pas perdre la guerre!” (Charles de Gaulle), that means “A country that produces over 300 types of cheese cannot lose the war!”.

Indeed, France manufactures over 1000 different varieties of cheese. The main type of milk used in its production is cow, but we can also find sheep's milk, goat's and buffalo's cheese.

To guarantee its quality, this gastronomic delicacy is now subject to various regulations. There are more than 40 types that have an “appellation d'origine controlee” (A.O.C). This A.O.C. is a standardization seal that encourages producers in the region of origin to manufacture in a traditional way.




Serra da Estrela Cheese


Serra da Estrela Cheese is a Portuguese cheese obtained from raw sheep's milk, from the Serra da Estrela Bordaleira or Churra Mondegueira breed. It is a ripened cheese, which can have buttery semi-soft buttery yellowish white paste (Serra da Estrela cheese) or a semi-hard to extra-brownish orange paste (Serra da Estrela old cheese).


This cheese has a controlled designation of origin (DOP). The earliest mentions of this cheese date back to the 12th century, making it the oldest of Portuguese cheeses. It is one of the most famous sheep cheeses in the world. It was present at the royal tables and was even evoked by Gil Vicente in the 16th century.




Production Method

  1. The process of obtaining Serra da Estrela DOP Cheese begins with the manual milking of the sheep, followed by the filtration of milk through white cloths.

  2. The milk is heated to 28-32 °C and salted.

  3. To this is added the flower of the thistle Cynara cardunculus (about 0.2 to 0.3 g), previously ground with salt.

  4. After 45 to 60 minutes, the curds are manually cut and filtered again to remove the remaining serum.

  5. Once the molding, pressing and salting steps have taken place, the maturation follows. This occurs in two phases:

  • The first occurs until the 15th-20th day, at a temperature of 6 to 12 °C and a relative humidity of 85 to 90 %. Daily turns and washings are performed.

  • The second phase lasts until the 45th day at a temperature of 6-14 °C and a relative humidity of 90 to 95 %. Here the turns and washes are done sporadically, depending on the appearance of the crust.


Note: For the manufacture of Serra da Estrela Velho Cheese, the same temperatures and relative humidity are used, varying only the minimum ripening time of 120 days.


Serra da Estrela cheese characteristics: The dimensions of Serra da Estrela PDO Cheese are 9 to 20 cm in diameter and 4 to 6 cm in height. It has a mild, clean and slightly acidic flavour and aroma. Regarding Serra Velho Cheese, the diameter is between 11 and 20 cm and the height between 3 and 6 cm. It has pleasant, persistent, clean aroma and taste, strong to slightly strong and slightly spicy and salty.




Case of study

High Pressure, a new and non-thermal preservation method of the Serra da Estrela cheese



A group of researchers from the University of Aveiro has studied alternatives to increase the shelf-life of Serra da Estrela cheese. One of the strategies envolves the use of a non-thermal technology: High Pressure Processing (HPP).


But what does this technology consist of?

HPP is a cold pasteurization technique by which products, already sealed in its final package, are introduced into a vessel and subjected to a high level of pressure transmitted by water. This technique tends to maintain the sensorial and nutritional properties of food, because of the absence of heat treatment, and maintains its original freshness throughout the shelf-life.


Level of pressure applied during a High Pressure treatment.


Illustrative scheme of the steps that occur during 1 cycle of a high pressure treatment.


Ok, but what did researchers do exactly?

Researchers applied high pressure treatments with different intensity levels: 400, 500 and 600 MPa for just 10, 5 and 3 minutes, respectively, to Serra da Estrela cheeses which were made from raw milk. Some cheese samples were not treated, to be used as a control.

Then, they stored all cheeses at 5ºC for 100 days in order to perform laboratory analyses and evaluate the effect of this treatment on the shelf-life and quality of cheeses. Results were compared with control cheese (untreated).


And what effects did researchers find out?

This non-thermal treatment led to a reduction in the microbial content of the Serra da Estrela cheeses, and therefore, increased their shelf-life. Also, the authors observed that cheeses treated by HPP showed a lower oxidative degradation of lipids (fat) than untreated cheeses.


In sum, High Pressure Processing is non-thermal technology with great potential to be used as a preservative method of Serra da Estrela cheese, and we hope that its commercial application will happen soon.


References

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