FR2475857A1 - Mfr. of cheese stabilised against butyric swelling - by adding lysozyme during mfr. - Google Patents

Abstract

In the mfr. of "cooked pressed paste" cheese (i.e. of the Gruyere, Emmental, Comte or Beaufort type), an effective amt. of a lysozymic material (I), i.e. a material capable of lysing the spores of butyric ferments, is added in the course of cheese mfr., esp. before cured formation. (I) is pref. a mixt. of lysozyme or a lysozyme salt (esp. hydrochloride) and one or more salts contg. Na and/or Cl ions. A prefd. mixt. comprises 80-85% lysozyme hydrochloride (Ia) and 15-20% NaCl. (I) is pref. added in an amt. such that the lytic titre of the medium is 100-1000 IU/ml. Using a material with a specific activity of 25,000 IU/mg., the amt. added is pref. 4-40 g. per 1000 litres of milk (esp. 20 g. when the milk contains 13,000 butyric spores). Addn. of (I) stabilises the cheese against delayed fermentation or "butyric swelling".

Description

PR5CvDE D MANUFACTURE OF CHEESES WITH PRESSED PASTE,
BAKE, STABILIZE
The subject of the invention is a process for the manufacture of stabilized pressed, cooked cheeses.

It is recalled that by the expression "pressed, cooked cheese" is meant the cheeses of the group including notably Gruyère, Emmental, Comté, neaufort
It is further recalled that the dough of the abovementioned cheeses is said to be "stabilized" when it is no longer the seat of the phenomena known as "late fermentation" or butyric swelling which appear due to the presence of microorganisms known under the name of butyric ferments 3 these phenomena also occurring in the case of pressed uncooked pasta which include in particular the cheeses known under the names of Gouda, Edam and others,
The late fermentation results, during the ripening, by a metabolism of the lactic acid present by producing a gaseous release which causes serious defects of texture which can go as far as the bursting of the grinding stones and the devalorization or the loss of the corresponding cheeses.

To avoid these phenomena, it is either necessary to make sure that the dough does not contain butyric ferments - whose sporulated form is, as is known, very resistant - or to act against the butyric ferments present.

In the case of pressed and cooked pasta, only the first part of the alternative is therefore tail app: in practice, we try to eliminate as much as possible the spores present by using bacterofugation, or we sort the milks at the entrance to manufacturing plants.

 Bacterofugation is not absolutely effective, all of the spores are not eliminated and the loss of cheese during ripening by germination of the remaining spores is not negligible.

The sorting of milks consists in separating the milks rich in butyric ferments from those which are poor in butyric ferments; the use of milks rich in buttery ferments in the manufacture of pressed and cooked cheeses, results in highly downgraded cheeses.

The object of the invention is therefore, above all to provide a method which remedies these drawbacks and which eliminates as much as possible the risks of late swelling.

However, the Applicant Company had the merit of finding, after extensive research, that it was possible to eliminate the butyric ferments in the process of manufacturing cheeses of the genus in question, by implementing 'a particular enzyme, lysozyme.

This finding is all the more unexpected since
- the thermal conditions (temperature-time pair) of the manufacturing process should a priori rule out any use of enzymes known for their brittleness under these conditions;
- the lysozyme exerted its lysing action well on the butyric ferments without exerting with regard to the propionic and lactic bacteria essential during the ripening, the negative action which is attributed to it by the scientific literature of the field considered and which a priori, should have prohibited its use (cf. in particular the article "Milchwirtschaftliche Berichte aus den Bundesanstalsten Wolfpassing und Rotholz" 1970, p. 169 - 199).

 It follows that the process according to the invention is characterized in that it comprises the addition, during the manufacture of the cheeses and more especially before the formation of the curd, of an effective amount of lysozyme, c that is to say capable of lyzing the spores of butyric ferments present.

 The invention also relates, as new industrial products, cooked pressed cheese with the above effective amount of lysozyme.

 According to an advantageous embodiment of the above process, the lysozyme is used in an amount such that the lytic titer of the medium is from approximately 100 to approximately 1000 IU / ml, depending on the content of butyric ferments in milk. .

According to another advantageous embodiment of the above process, the lysozyme used is lysozyme from egg white, preferably in the form of the hydrochloride.

According to another advantageous embodiment of the above process, the lysozyme is used jointly with one or more salts providing Na + and / or C1 ions, preferably NaCl.

According to another advantageous embodiment of the above process, the implementation of lysozyme is carried out when the milk is still in the liquid phase, preferably after the seeding of the lactic ferments and just before the curd solidifies.
The invention also relates to other arrangements which will be discussed in the additional description which follows and which relates to advantageous embodiments.

Consequently, proposing to make a pressed, stabilized cooked cheese, it is done as follows or in an equivalent manner.

During the manufacture of the cheese and advantageously before the first stage of cooking, an effective amount of lysozyme is added to the dough, it being recalled that said manufacture comprises the following stages:
1) Preparation of milk
The milk is inoculated with the lactic ferments containing in particular in the case of Emmental, the following two strains
- Lactobacillus helveticus,
- Streptococcus thermophilus.

 After having carried out the lactic seeding and allowing the milk to mature for a certain time, the lysozyme is added in amounts such that the lytic titer corresponds to that which has been defined above, according to the number of butyric spores.

20) Emprésuraae and curd cooking:
The milk is heated to the temperature of about 320C, then the rennet chosen from those commercially available is introduced. When all of the milk has passed into the curd state, the shelling operation is carried out. It is left to stand for approximately 2 to 3 minutes, then the whole is stirred for approximately 5 minutes and heated in several stages
- the temperature of the curd is gradually raised to around 300C;
- the temperature is raised to that usually used for cooking the curd;
- Then the latter temperature is maintained for approximately 40 to 50 minutes, during which the curds are continuously stirred.

3) Molding and pressing the curds
The curd is removed from the tank, then molded, then pressed. The cheeses thus obtained are then removed from the mold, introduced into a cold cellar and possibly soaked in a brine bath for 2 hours.

4) Affinaae
Refining is carried out in two stages
- a stage during which the cheese is kept in a cold cellar (8 - 100C);
- a second stage during which the cheese is kept in a hot cellar (22 to 230C) until the openings have formed regularly.

The cheeses are then stored in a cold cellar.

 Lysozyme, a mucolytic enzyme is present in particular in egg white, in saliva, nasal mucus, blood granulocytes, the pancreas, in a certain number of tissues and secretions of different animals, as well as in certain plants.

 It goes without saying that the lysozyme used in the context of the present invention can come from any source, but use will advantageously be made of egg white lysozyme.

The lysozyme used can be in base form but preferably the salt form is used since in this form the impurities are in the insoluble state, therefore more easily eliminated than the soluble impurities present when the lysozyme is in base form.

 By lysozyme in the form of a salt is meant in particular the salts obtained by salification of a tartie or of all of the basic functions of lysozyme.

 Mention may be made, as salt, of the salts whose anion comes from a mineral acid, in particular hydrochloric acid from an organic acid, in particular lactic acid or from an amino acid such as aspartic acid, glutamic.

 According to a preferred embodiment of the process according to the invention, use is made of lysozyme hydrochloride.

 According to another preferred embodiment of the process according to the invention, the lysozyme base or its salt is used in mixture with one or more salts which contain at least one of the two sodium and chloride ions, the effect of which has been observed. of potentiating the lytic activity of lysozyme.

 A particularly advantageous mixture used in the process according to the invention is that consisting of lysozyme hydrochloride and sodium chloride.

 Preferably, the content by weight of this mixture of lysozyme hydrochloride ranges from approximately 80 to approximately 85 (for a respective sodium chloride content of approximately 2G to approximately 15V).

 Lysozyme can be obtained from the raw materials containing it by various methods, in particular precipitation by a salt, in particular NaCl or by bentonite, by fixing to an ion-exchange resin, by ultrafiltration or any other method. selective separation.

The egg white lysozyme, which is advantageously used, is precipitated by treatment of the egg white with an excess of NaCl.

The lysozyme obtained by this method is lysozyme in the base form, containing Nazi.

 Lysozyme hydrochloride is obtained by treating (according to a conventional method) the lysozyme base containing NaCl (obtained during the step described above) with hydrochloric acid, which provides a mixture of lysozyme hydrochloride and NaCl in proportions directly usable in the context of the process according to the invention.

 In the remainder of the text, the term active ingredient lysozymic will denote formulations containing lysozyme base, lysozyme salts, or their mixtures with one or more salts containing at least one of the sodium and chloride ions.

The amount of lysozymic active ingredient to be introduced during the process for making cooked cheeses is a function of the lytic activity or lytic titer of the lysozyme used, measured in IU / ml and determined according to the method described by David SUGAR, in " Biochemica and
Biophysica Acta ", 1952, vol. 8, p. 302 - 304.

In the context of conventional manufacture and without changing the other parameters, the amount of lysozymic active material used is preferably chosen so that the medium into which the lad-ite material is introduced has a lytic titer of approximately 100 to approximately 1,000
IU / ml depending on the content of butyric ferments in milk.

Regarding the upper critical value of the lytic titer of the mixture, this must not exceed the value of approximately 1000 IU / ml in order not to change the value of the parameters compared to that which they have in the framework of the conventional manufacturing processes used to date and in particular the quantity of lactic ferments
When using a lysozyme of 25,000 UTng as the reference, the amount of lysozyme material to be added to the milk varies from approximately 4 g. at about 40 q.

per 1000 1. of milk, the exact quantity to be determined according to the dose of butyric ferments contained in the milk.

 Likewise, for a reference lysozyme of 30,000 IU / mg, the amount of lysozyme material to be added to the milk varies from approximately 4.8 q to approximately 48 y per 1,000 l of milk, the exact quantity being determine according to the dose of butyric ferments contained in milk.

For example, for a milk containing approximately 13,000 spores of butyric ferments per liter, approximately LO g has been introduced. of lysozymic active ingredient (lysozyme of reference to 25 OO0 IU / mg) per 1000 1. of milk. The cheeses obtained do not exhibit butyric fermentation compared to a control sample produced without resorting to the use of lysozyme.

 Knowing the lytic titer of the lysozymic active ingredient used, the quantity to be introduced into the volume of milk or curd to be treated is determined by calculation as a function of the number of buryric spores per unit volume.

The active ingredient lysozymique must not contain pathogenic germs.

 It is advantageous to use the lysozymic active material together with one or more adjuvants which serve as a support for it.

 Preferably, an inert material is chosen with respect to the constituents used in the composition of the cheese, that is to say in particular with respect to the milk and the curd, providing as little foreign compounds as possible, preferably soluble in milk, non-toxic, acceptable to the human body and having bacteriological qualities such that it can be used in the manufacture of cheeses.

It has been indicated above that the lysozyme, that is to say of course the lysozymic active material, is advantageously added before the stage of cooking the curd. It is particularly advantageous to add the lysozymic material when the milk is still in the liquid phase, that is to say before the quail solidifies.

It is in fact preferable to have a good distribution of the lysozymic active material within the material which is used to prepare the cheese, this distribution being easier to obtain when the medium into which the material is introduced is liquid; the introduction of lysozyme once the milk is curdled, that is to say after the renneting phase, is still possible but requires special conditions so that the active ingredient remains in the curd.

According to yet another embodiment of the invention, it is preferable to introduce the lysozymic active material into the liquid phase of the milk, after sowing the lactic ferments and immediately before the formation of the curd so that the active material is distributed. then very homogeneously in the medium.

When the lysozymic active material is introduced into the liquid phase of the milk and in the case where the active material is in the form of a powder, a premix of the latter will advantageously be carried out in a liquid miscible with the milk, inert to milk, non-toxic, acceptable to the human body and having bacteriological qualities such that it can be used in the manufacture of cheeses, in proportions between the lysozymic active ingredient and the premix liquid, such that the lytic titer of the mixture corresponds to the values indicated above, in order to obtain a better distribution of the active material within the liquid milk.

 Water and milk are advantageously preferred as premix liquids. When the lysozymic active material is associated with a support, having the above-defined characteristics, it is introduced directly into the milk in the liquid phase, without having to use a premix.

 The following example, relating to a manufacturing process for Emmental, illustrates the characteristics of the invention.

16,200 liters of milk are heated to 330C and left to mature for one hour in a natural way.

us, the following two ferments are added to the milk:
- Lactobacillus helveticus,
- Streptococcus thermophilis.

 The maturation is allowed to continue for approximately one hour, then the lysozyme (at 25,000 UT / mg) previously diluted in milk, at the rate of 4 g, is introduced into the milk medium. lysozyme per 1,000 liters of milk.

Then added the rennet powder sold under the brand "Hansen" reconstituted at a force of about 1/15 OOOe. The setting time is approximately 22 to 24 minutes, the mixture always being at the temperature of 330C.
The curd is left to harden for 5 minutes before slicing and brewing it for 6 to 8 minutes.

 It is then raised to the temperature of 530C in 30 to 45 minutes. Then, a stirring is carried out for a period of 30 to 40 minutes, stirring during which the temperature decreases from 530C to 51-500C. The curd is introduced into molds and then the molded curd is subjected to three successive increasing different pressures for 16 hours using a manual press of the type used in the manufacture of pressed cheese, and mark "TREVILLERES", the weights used to communicate the successive increasing pressures being respectively 500, 1,500, 2,500 kg. During pressing, the curds are turned and the fabric is changed.

 The 18 cheeses thus obtained are put in a cold cellar at a temperature of around 100C one day, then soaked for 48 hours in a brine tank. They are then placed in a cold cellar for 10 days and then in a hot cellar (22-230C) for maturing.

 The cheeses thus obtained do not exhibit butyric fermentation. Lysozyme is found in finished cheeses in an amount at least equal to approximately 70% relative to the lysozymic active material introduced under the conditions for carrying out the process according to the invention, the missing 30% being passed during preparation , in whey.

To prove the presence of lysozyme, added in accordance with the invention, in the dough of ready-to-eat cheeses, which are also targeted by the invention, a method can be used which consists in preparing a "cheese milk", c 'is to say a mixture of cheese and hydrochloric acid; we can use proportions of 10 g. cheese for 50 ml of 0.1N concentrated HCl

In such samples, the presence of lysozyme is detected according to a spectophotometric method in an opaque medium, derived from the method of David SUGAR for the determination of the specific lytic activity of lysozyme and to which it is referred to above.

Following this, and whatever the embodiment adopted, there is thus a process for the preparation and preservation of pressed cheese,
cooked whose implementation is simple and which proves to be remarkably effective. There are also cooked, stabilized pressed cheeses, in which the phenomenon of late butyric fermentation does not occur, which can therefore be matured for longer and in which lysozyme, which has no toxic character, is harmless. with regard to health and does not in any way modify the properties and quality of the cheeses which contain it.

 The invention is obviously not limited to the embodiments described above by way of examples and a person skilled in the art can make modifications to them without departing from the scope of the claims below.

Claims (8)

 RFVEMDICATIO5S 1 - process for the preparation of pressed, cooked, stabilized cheeses, characterized in that it comprises adding, during the production of the cheeses and more especially before the formation of the curd, an amount of material effective lysozymic active, that is to say able to lyse the spores of butyric ferments present. 2 - Process according to claim 1, characterized in that the lysozymic active material consists of lysozyme base, or lysozyme salt, or their mixtures with one or more salts containing one at least of the two sodium and chloride ions. 3 - Process according to claim 2, characterized in that the lysozyme salt is lysozyme hydrochloride. 4 - Method according to claim 2, characterized in that the lysozymic active material consists of a mixture of lysozyme hydrochloride / sodium chloride, preferably in the weight proportions of about 80-852 lysozyme hydrochloride for about 20- 15 of NaCl. 5 - Method according to claim 1, characterized in that ia lysozymiquc active material is implemented in an effective amount such that the lytic titer of the medium is from about 100 to about 1000 IU / ml. 6 - Method according to any one of claims 1 to 5, characterized in that one uses about 4 to about 40 g. of lysozymic active ingredient per 1000 l of milk, for a reference lysozyme used of approximately 25 to 100 IU / mg. 7 - Method according to any one of claims 1 to 5, characterized in that the lysozymic active material used for a milk containing about 13,000 butyric spores is about 20 g. per 1,000 liters of milk, when the reference lysozyme is approximately 25,000 UT / mg. 8 - Pressed cheese, cooked, stabilized, obtained by implementing the method according to any one of claims 1 to 7