Known since Roman times and favorite of Charlemagne, Roquefort cheese is the result of exposing sheep’s milk to a mold called Penicillium roqueforti , left to age for at least three months in the limestone caves of the Combalou Mountains, near the village of Roquefort, located in the southwest France.
Composition and reactions
Also called Blue veined cheese or blue cheeses , due to the development of Penicillium roqueforti mold in the areas of the cheese paste, these cheeses have regional names. Even though she is not the “queen of cheese,” as many claim, Roquefort is one of the oldest and best known in the world.
The limestone caves of the Combalou mountains are the only place where real Roquefort cheese is aged. It has a creamy, consistent texture and a spicy, spicy, somewhat salty taste. The interior is white, with blue vines, and the bark is pure white. It is presented in short and thick cylinders, covered in foil. The original Roquefort cheese is recognized by the specific label on which a red sheep is drawn.
The name “Roquefort” is protected by law against imitations. Roquefort cheese has the status of designation of origin (PDO) being made in France from raw sheep’s milk. Studies have shown that, in addition to cultures of lactic acid bacteria and Penicillium roqueforti, the microflora of Roquefort cheese made from raw sheep’s milk contains yeasts, lactobacilli, micrococci, staphylococci, coliform bacteria.
Lactococci are always dominant in cheese, but yeasts and Leuconostoc species are also present from the beginning of maturation. Lactobacilli, especially Lactobacillus casei and Lactobacillus plantarum reach a maximum number before salting. The number of staphylococci decreases drastically in the first 48 hours, and that of coliform bacteria decreases constantly, in the first month of maturation. After salting, the surface microflora contains mainly yeasts and micrococci.
The major role of Penicillium roqueforti in the maturation process is recognized, but in conventional cheese made from raw milk, the secondary microflora is also of essential importance for the formation of sensory characteristics. However, Blue cheeses can be manufactured, as happens in many European countries (including Romania), by unconventional, coagulant processes.
Proteolysis is very intense in cheeses with internal mold: over 50% of N-total is soluble is soluble in matured Roquefort cheese and about 65% in Danish Blue. In the last assortment, 10% of the N-total is free amino acids. The contribution of Penicillium roqueforti to proteolysis is important, determining that after 40 days of maturation N-soluble at pH 4.6 and N-soluble in phosphotungstic acid to represent 50%, 30% and 10% of the N-total of Roquefort cheese, respectively.
As with proteolysis, lipolysis in this type of cheese is much more developed than in other cheeses. In cheeses with mold in the paste, 65-100 meq / 100 g of free fatty acids were determined, representing 18-25% of the total fatty acids. Penicillium roqueforti has been shown to have two lipases: one with an optimal pH of activity in the acidic domain, another in the alkaline zone.
It is unanimously accepted that the specific taste and aroma of moldy cheeses in pasta are determined by the presence of methyl ketones. The most abundant are 2-heptanone and 2-nonanone, but in smaller proportions, but with a contribution to flavor, are 2-propanone, 2-pentanone, 2-undecanone and 2-tridecanone.
A number of factors (temperature, pH, physiological state of the mold, the ratio between the concentration of fatty acids and SU in the spores) influence the formation of methylketones. The volatile fraction in cheeses contains, in addition to methyl ketones, many other substances. Secondary alcohols (2-pentanol, 2-heptanol, 2-nonanol) are formed by reduction of methyl ketones. Other alcohols, esters, aldehydes, lactones were in the internal mold cheeses.