GB2309880A - Method for the preparation of cheese - Google Patents

Description

- 1 2309880 METHOD FOR THE PREPARATION OF CHEESES AND DEVICE IMPLEMENTING

THIS METHOD The present invention relates to a method of preparing cheese and to a device for the implementation of this method.

The manufacture of cheese has existed for a very long time and it is carried out starting with cow's milk, goat's milt, ewe's milk, mare's milk and the milk of other grazing animals. According to the usual practice in this matter, the milk is heated up to a temperature of the order of 30' to 35'C, which corresponds to that of the animal's body, and then it is curdled by rennet, which consists of extracts of calf, kid or lamb stomachs, chopped up and macerated; the action of this rennet, which contains chymosin, allows the curdling of the milk.

The coagulation or curdling of the milk results in the formation of a solid phase, called curd, and of a liquid phase, called whey.

The extraction of the whey from the solid phase, which is more or less slow, is called "syneresis of the coagulum".

The coagulate or curd obtained is generally chopped up into pieces to allow better extraction of the whey. These pieces of curd are most often of predefined size depending on the type of cheese desired and are subjected to pressure in order to extract the whey contained in the coagulum after they are put into a perforated mould having specific dimensions.

The moulds are most often turned over several times to perfect the extraction of the remaining whey and are generally maintained under pressure.

After removal from the mould, the productsare salted with dry salt or with brine, dried and are most often subjected to a maturation or ripening stage, during which they are turned over many times.

They can also be subjected to a bacterial action or to the action of internal or external moulds before maturation in order to make the proteins and lipids contained in the cheese digestible and to inhibit the development of bacteria which are bad for human consumption or to develop specific tastes or colours.

2 - As time progresses, manufacturing techniques are being improved, in particular by the improvement of better controlled rennets or by the use of acidifying lactic yeasts causing the coagulation of the milk on the one hand and, on the other hand, by using well isolated ferment stocks, which can be added at the same time as the rennet or before or during the ripening stage.

For reference, it is possible to consult the work entitled "Les Fromages" by Robert J. COURTINE, published by Larousse in 1973-1987, in which the various cheeses are classified according to their manufacturing method as fresh cheeses and matured cheeses.

Among the fresh cheeses a distinction is made between those which curdle slowly and which can be salted, like Demi-Sel or Gournay Frais, or nonsalted like the Petits-Suisses, Fontainebleau or NeufchAtel Frais, and those which curdle quickly like green cheese.

Among the matured cheeses, a distinction is made between those which are produced with spontaneous draining and those produced with accelerated draining.

The first category includes cheeses which curdle slowly and use external moulds such as Brie, NeufchStel, Gourney and Saint-Marcellin, and cheeses which curdle quickly and use external moulds, like Camembert or Coulommiers, or with rinds of various types like goat, Langres, Bourguignon, Epoisses, Vend6me or Olivet; they also include other cheeses obtained by cutting up with external mould, like Carri6 de 1'Est, Maroilles or Pont1'Eveque Fermier, or with internal moulds like Roquefort, Gorgonzola and Bleu d'Auvergne or with rinds, like MUnster, Pont 1'Ev6que Laitier, Livarot and G6rom6.

The second category includes cheeses obtained by cutting up and stirring, with internal mould like Fourme d'Ambert or with rind like Bel Paese or Tilsit, and possibly subjected to pressure, with external mould, like Tome de Savoie or Saint-Nectaire, or with rind like Port Salut, Saint Paulin, Dutch and Reblochon; they can also have undergone an additional crushing operation, like Cheddar, Chester, Cantal or Laguiole or can have undergone a baking like Emmental, Gruyre or Compte.

However, whatever ripening technique is used, all of these manufacturing techniques necessitate manual operations which cannot be avoided, particularly for pressed cheeses with divided curd and accelerated draining, which necessitate a lot of labour whose cost burdens the economic exploitation of this type of cheese, as clearly indicated in Andra Eck's book entitled "Le Fromage" and published by Lavoisier in 1984. Furthermore, moulding operations require heavy investment in perforated metal moulds whose maintenance, bulk and hygienic conditions of use also give rise to considerable costs.

The purpose of the present invention is to overcome these disadvantages by proposing a method of manufacturing cheeses by curdling milk, separation of the whey, shaping into blocks and ripening. characterized in that the shaping of the cheeses into blocks is carried out by inserting the curdled milk under pressure in a casing of appropriate size for carrying out the draining and the moulding, followed by cutting up the casing filled with curdled milk and drained ' into slices whose thickness depends on the desired thickness of the finished cheese.

The invention also relates to a device for the implementation of this method which is characterized by a vacuum pump for inserting the curdled milk under controlled pressure inside the casing, the said casing preferably being placed over a forcing tube discharging inside the casing in order to fill it and provided with a system for extracting the whey.

The use of a casing, which can be made of cellulose material, plastic material or collagenous material, for the shaping of cheeses into blocks makes it possible to replace the individual metal moulds of the traditional methods by a single flexible mould for a series of individual cheeses.

Furthermore, the handling of the casings filled with curd is facilitated, their bulk is much less than that of individual moulded cheeses and their cutting up, like slices of sausage, has the advantage of being easy 4 and of retaining a portion of the casing on each cheese to be ripened, which serves as a mould during the final maturation and maintains the shape of the finished individual cheese.

It will be observed that the first stages of preparation of a cheese, such as the curdling of milk by the addition of rennin and/or acid, the breaking up of the curd by mechanical stirring with reduction of the size of the particles of the coagulum and a draining of the curd in the stirring tank by drawing of f the whey need not be modified in the method according to the invention.

on the other hand, the following stages of additional draining, moulding in perforated moulds in order to favour the extraction of whey, pressing or not pressing with turning over of the moulds, removal from moulds, salting with turning over of the products and finally maturation or ripening with turning over of the products are all profoundly modified, or even eliminated, in the method according to the invention.

In effect, the stage of additional draining of the curdled milk is usually carried out in a cloth, by ultrafiltration or centrifuging or by any other means of separating a solid phase from a liquid phase; in the method of the invention, the curdled milk is forced under pressure into a casing, which makes it possible to squeeze out the curd by the counter- pressure of the casing and to expel the whey which can be drawn of f in the vicinity of the mouth of the tube for inserting the curdled milk into the casing and/or squeezed out through the surface of the casing, particularly if the latter is permeable or even perforated.

The traditional stage of manually moulding the curdled milk by placing it in a mould, perforated or not perforated, is completely eliminated by the method according to the invention, since the curdled milk is moulded directly in the casing. This modification allows a considerable gain in productivity and reduction of size and, above all, avoids the onerous maintenance and cleaning of moulds. In fact, with the conventional use of metal moulds, the problem of cleanliness is crucial and particularly difficult for perforated moulds, which are used by preference because the speed of expulsion of the whey has an effect on the physical, chemical and microbiological properties of the cheese. It is appropriate to note that a mould made of rigid material and preferably perforated to allow expulsion of the whey is expensive and that the possibility of doing away with it according to the method of the invention represents an improvement which is particularly advantageous in terms of economy.

Furthermore, the usual stage of placing or not placing the moulds under a press and turning over the moulds in the conventional methods of manufacturing is cheese is no longer necessary in the method according to the invention.

In fact, up until now it was considered as essential to turn the moulds over in order to prevent their perforations from becoming stopped up by curd and thus presenting a risk of non-expulsion of the whey. Furthermore, the stagnation of the whey around the cheese favours the germination and proliferation of a noxious fungal flora. And, during this stage, the susceptibility of the curd to free water is very high and there is a risk of rapid growth of harmful bacteria and other undesirable germs. On the contrary, in the method which is the subject of the present invention, the product being placed in a very strong casing, perforated if necessary, the casing can be placed under constant tension, for example by means of a jack, by pulling on one of its ends, which causes the expulsion of the whey from the casing through its perforations if it has any.

A similar result would be obtained if the sausages filled with curdled milk were put into shape, of great length, and a uniform pressure applied over their whole length.

In the case of a non-perforated casing, a portion of the liquid can evaporate through the skin of the casing, because the latter is permeable to water vapour.

It will be noted that, during this operation, any turning over of the product is of no use, the casings being able, for example, to be suspended like sausages.

Instead of the conventional stage of removal from moulds, the method according to the invention comprises the cutting up of the casing of great length and of appropriate size containing the curd into slices of the desired thickness using tools which are commonly used in the food industry, such as a slicing machine used in the curing or baking industries. This cutting up operation can easily be carried out automatically.

Cheese products manufactured according to the methods of the prior art were removed from their moulds and treated with salt or brine and generally inoculated with a specific microorganism, then turned over several times, to prevent the collapse of the product and a rounding of its edges. These various operations are obviously manual. In order to avoid these frequent turnings over of each individual cheese, they were often, in the case of certain "traditional" cheeses, wrapped with beech leaves, bark or spruce leaves. In the method according to the invention, the productsmaybe placed in brine or salted and inoculated, as before, but it is no longer necessary to turn the products over frequently because the section of casing holds the edges of the product firmly and prevents their collapse. Because of this, turn-overs are less frequent or even unnecessary.

Finally, the many turnings over of the products during the final maturation stage in the conventional methods of manufacturing cheese become less important in the method according to the invention because, when a permeable casing is used, for example a cellulose casing reinforced with cellulose fibres, the drying of the cheese is the same on both of its faces and on the lateral edges. Such a phenomenon is well known in the curing industry for making dry sausage. Furthermore, if inoculation with enzymes of the cellulolytic type is carried out, the section of cellulose casing progressively becomes converted into glucides and disappears by enzymatic digestion before the end of the ripening phase. If an impermeable casing us used, the rind which forms on the side edges of the products is limited. This rind, which represents a loss to the consumer, sometimes makes brushing operations necessary before being put on sale. The absence of rind therefore constitutes an advantage and can result in the creation of new varieties of cheeses. Insofar as the section of casing remains on the finished product, it is possible to use it for commercial purposes by colouring, printing or personalisation of the products offered for sale.

The method according to the invention can make use of casings of great length, such as those commonly used in the delicatessen trade in pleated form for the manufacture of hams, sausages, mortadellas and other products. In particular, the casings can be made of cellulose material, possibly reinforced with fibres and more particularly with natural fibres, with non-woven fabric, with paper or with textile. The casings can also be made of plastic material, particularly those chosen from among the polymers and copolymers of ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, polyesters and polyamides. The casing can be made of cellulose material, particularly of reinforced cellulose material and can have, on one of its faces, a coating which is impermeable to water and to oxygen. It can also be made from a collagenous substance, particularly reinforced with fibres, a textile support or paper.

It is particularly advantageous to use a cellulose material for the casing because it can be manufactured with different porosities according to the cheese substance with which it is placed in contact in order to form a barrier to fatty substances and to microorganisms whilst allowing the passage of water vapour.

Independently of its chemical structure and of its dimensions, the casing is preferably perforated by holes having a diameter of between 1/10th and 5 mm, or more particularly between 4/10 and 8/10 mm, at the rate of at least one hole, and more particularly of at least four holes, per 10 cm' of casing surface.

The device according to the invention is shown in a particular embodiment in the two accompanying figures which show a forcing tube (1), fed under pressure at its left hand end with curdled milk by a pump (2) and emerging at its right hand end inside a casing (3).

The casing is generally in the form of a flat or pleated casing (Figure 1) or is pleated on a hollow mandrel (Figure 2, reference 4), which can be slipped over the outside of the forcing tube.

After the casing is fitted over the forcing tube (1), the casing is partially unfolded beyond the mouth (5) of the tube and its right hand end is closed with a clip.

There is installed, for example, for a pleated casing (3) on a hollow mandrel (4), a ring (6) which controls both the partial sealing and the braking of the casing. In the case of a flat or pleated casing (3) without a hollow mandrel, it is possible to place one or more rings, one of which (10) has the function of braking the casing and another of which (6) allows the controlled expulsion of the whey towards the rear.

The forcing tube (1) is fitted with a device for expelling the whey under vacuum in the direction opposite to that of the flow of curdled milk delivered by the pump.

The device for expelling the whey under vacuum can consist of perforations (7) made through the walls of the forcing tube mouth and a pipe (8) connecting the outlets of all of these perforations (7) and connected to a collecting chamber (9) in which a vacuum is produced.

By means of this device, when the pump delivers the curdled milk under pressure into the casing, which inflates as it becomes filled, the coun ter-pres sure of the casing partially forces back the whey between the braking ring (6) and the mouth (5) and the whey thus forced back is evacuated by suction through the perforations (7) and the pipe (8) towards the collection chamber (9), in which a vacuum is produced, where it is 9 collected.

A feature of the device according to the invention consists in the interposition of a diaphragm (11) at the inlet of the forcing tube (1), necessitating a very high pressure in the pump and allowing superior extraction of the whey.

The invention will now be illustrated by a particular implementation.

litres of unskimmed, unprocessed cow's milk, from the previous evening's milking and cooled to +100C at pH 6.5 was placed in a container of capacity 150 litres which was thermos ta t- control led at +35'C, where it was heated up.

At the temperature of 350C, 60 ml of rennin, containing 500 mg/1 of chymosin, manufactured by the CoopC.rative Phamaceutique Franqaise de Melun, 77000, was added.

The mixture obtained was stirred manually for 1 minute.

After 1 hour, the coagulum was cut up with a knife and then stirred and then left to separate.

In this way 85.73 kg of whey was evacuated and 22.8 kg of curd was collected, for a weight of 108.53 kg of unprocessed milk used at the start.

These 22.8 kg of curd were fed by a HANDTMANN VF20 pump into a forcing tube, consisting of two concentric tubes, one having a diameter of 38.8 mm and a thickness of 1.5 mm and the other having a diameter of 52 mm and a thickness of 1.5 mm. An evacuation system connected to a vacuum pump comprised a collection chamber connecting with the outer tube close to its base, this outer tube comprising 40 holes of diameter 2 mm, disposed symmetrically around a circumference at a distance of 26 mm from the mouth of the tube.

The forcing tube was fitted with a stick of pleated casing made of cellulose material reinforced with a non woven fabric, known by the trade name FIBROUS 95 SL SHIRMATIC 403, having a length in the unfolded state of metres and perforated at the rate of 0.9 holes of 6/10 mm diameter per CM2 of casing surface (9 holes per - is cm').

The device for filling casings also comprised a braking and sealing ring having an internal diameter of 53.5 mm and a width of 6 mm and a POLYCLIP FCAS 3.451 double clip, equipped with 18-12-5-2.5 LR clips.

The 22.8 kg of curd was delivered by the pump into the perforated FIBROUS casing, which was inflated to a calibre of 102-103 mm diameter. 19.03 kg of curd was retrieved in the form of three sausages; 3.22 kg of whey was retrieved in the suction circuit of the pump and 0.50 kg of whey was retrieved in the vacuum evacuation system connected to the holes disposed in the vicinity of the mouth of the forcing tube, that is to say a yield of 83.7 %.

The three sausages constituting the products obtained were suspended under tension in a refrigerator. An additional draining of whey was carried out and, after 92 hours, a 10.9 kg sausage then weighed only 8.51 kg, that is to say a yield of 78.1%.

The sausages thus obtained could then be cut with a knife, without difficulty, into disks of thickness 4 cm and these disks were stored flat in a refrigerator for ripening.

It was observed that the products retained their cylindrical shape well and that the cheese dried in the same way on the top and bottom surfaces and on the lateral surfaces.

The results for the various substances are summarized in the following table:

Table

Substance Weight in Kg Percentage Weight Unprocessed milk 108.53 Base 100 Drained whey 85.73 79 Curd 22.8 21 Whey expelled during filling 3.72 after 92 hours 2.39 Total Whey X lled 91.84 84.6 Final curd 15.4 It will be noted that the method and the device according to the present invention can be perfected: thus, if the pump has a compression zone, the whey can be extracted by the suction system with which it is equipped.

It is also possible to regulate the evacuation of whey during the filling operation by varying the adapted clearance between the single braking ring and the forcing tube mouth so that the ring also provides the sealing around the said tube.

Finally, it will be noted that the casing can be perforated or not perforated and used as it is without preliminary soaking in water, in order that it becomes moistened, in such a way as to develop a high counterpressure favouring the squeezing out of whey while the casing is being filled with the curdled milk, by varying, in particular, the adjustment of the braking ring on the forcing tube.

During the additional draining after filling the casings with curdled milk in the form of sausages, it is possible to readjust their shape in order to compensate for the loss of volume caused by the draining, for example by traction applied to one or both ends of the sausages and/or by pressure applied uniformly over the 12 - entire length of the sausages.

If a non-cylindrical shape is desired, the sausages can be shaped in very long moulds during the additional draining stage.

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Claims (33)

CLAIMS:

1. Method of preparing cheeses by curdling milk, separation of the whey, shaping into blocks and ripening, characterized in that the shaping of the cheeses into blocks is carried out by inserting the curdled milk under pressure in a casing of appropriate size for carrying out draining and moulding, followed by cutting up the casing filled with curdled milk into slices of the desired thickness.

2. Method according to claim 1, characterized in that the casing filled with curdled milk is subjected, before cutting into slices, to a pressure, preferably under the effect of its own weight, possibly with readjustment of its shape.

3. Method according to claim 1 or 2, characterized in that in order to compensate for the loss of volume caused by draining, readjustment of the shape of the casing filled with curdled milk is carried out by the effect of traction and/or of pressure,.

4. Method according to any preceding claim, characterized in that the shape of the casing before it is cut into slices is obtained by shaping in a very long mould.

5. Method according to any preceding claim, characterized in that the cutting up of the casing filled with curdled milk into slices is carried out with a knife or with a slicing machine.

6. Method according to any preceding claim, characterized in that the casing is made of cellulose material, preferably of cellulose material reinforced with fibres, more preferably with natural fibres, non-woven fabric, paper or textile.

7. Method according to any of claims 1 to 5, 14 characterized in that the casing is made of plastic material, chosen from among the polymers and copolymers of ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, polyesters and polyamides.

8. Method according to any of claims 1 to 5, characterized in that the casing is made of cellulose material, preferably reinforced cellulose material, and has, on one of its surfaces, a coating which is impermeable to water and to oxygen.

9. Method according to any claims 1 to 5, characterized in that the casing is made from a collagenous substance, preferably reinforced with fibres, a textile support or paper.

10. Method according to any preceding claim, characterized in that the casing is perforated by holes having a diameter of between 0.1 and 5 mm at the rate of at least one hole per 10 cm2 of casing surface.

11. Method according to claim 10, characterized in that the casing is perforated by holes having a diameter of between 0.4 and 0.8 mm. 20

12. Method according to claim 10 or 11, characterized in that the casing is perforated at the rate of at least four holes per 10 cm2 of casing surface.

13. Method according to any preceding claim, characterized in that the curdled milk is inserted under pressure into the casing by pumping with a pump having a compression zone, preferably provided with a circuit for the evacuation of whey under vacuum.

14. Method according to claim 13, characterized in that the pump delivers into a forcing tube, whose mouth is fitted with a device for expelling the whey under vacuum in the direction opposite to that of the flow of curdled milk is delivered by the pump.

15. Method according to claim 14, characterized in that the forcing back of the whey is amplified by the interposition of a diaphragm at the inlet of the forcing tube.

16. Method according to claim 16, characterized in that the forcing back of the whey is caused by the filling counterpressure of the casing and in that its return in the backward direction is made possible by adjusting the clearance between the casing and the forcing tube, at the open end of the latter.

17. Method according to claim 16, characterized in that the casing used allows the forcing back of whey by the use of a single ring providing the sealing and the braking of the casing on the forcing tube.

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18. Method according to any of claims 1 to 5, characterized in that the perforated or unperforated casing is used as it is, without soaking, and makes it possible for a high pressure to develop favouring the separation of the whey, preferably with the perforated casing, during the filling of the said casing with curdled milk by varying the adjustment of the braking device.

19. Method according to claim 16, characterized in that the vacuum counter-flow evacuation device comprises the passage of the whey through the walls of the forcing tube and the collection of the whey through a pipe located inside the said forcing tube.

20. Method according to claim 6, characterized in that the casing made of cellulose material has a porosity according to the substances with which it is in contact and, preferably, forms a barrier to fatty substances and to microorganisms whilst allowing the passage of water vapour.

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21. Method according to any preceding claim, characterized in that the casing, preferably made of cellulose material, is inoculated before cutting up into slices so that it disappears during ripening.

22. Device for use for the manufacture of cheeses according to the method of any preceding claim, characterized in that it comprises a pump for inserting curdled milk under pressure into the inside of the casing.

23. Device according to claim 22, characterized in that the curdled milk under pressure is delivered by the pump into the casing by the intermediary of a forcing tube over which the said casing is slipped.

24. Device according to claim 23, characterized in that, close to its mouth, the forcing tube is provided with a device for expelling the whey under vacuum in the direction opposite to that of the flow of curdled milk delivered by the pump.

25. Device according to claim 24, characterized in that the device for expelling the whey under pressure comprises perforations made through the walls of the mouth of the forcing tube and a collecting chamber connecting the outlets of all of these perforations and allowing the collection through a pipe located inside the forcing tube.

26. A device for use in the separation of whey from curdled milk in the preparation of cheeses, the device comprising a tubular element for receiving externally a tubular casing, pump means for introducing curdled milk under pressure into the tubular element at an inlet end thereof, and means for withdrawing whey from the tubular element in the direction opposite to that of introduction of the curdled milk, the casing, in use of the device, being closed outwardly of the outlet end of the tubular element whereby the casing 17 is extended from tubular element as curdled milk is introduced under action of the pump means.

27. A device according to claim 26, in which the tubular element which has outer and inner walls which define a passage therebetween and the whey-withdrawal means comprises one or more apertures in the outer wall and a vacuum means connected to the passage, whereby, in use of the device, whey is withdrawn from the extended casing under vacuum in a flow direction opposite to that of introduction of the curdled milk.

28. A device according to claim 26 or 27, including at least one annular element located externally around the tubular element to leave an annular gap to accommodate the casing, the annular element(s) producing at least one of a partial sealing effect between the casing and the tubular element and a braking effect on the extension of the casing.

29. A device according to claim 27, including first and second annular elements located externally around the tubular element at spaced locations with the aperture(s) of the whey- withdrawal means therebetween, the annular elements cooperating with the casing to control extension thereof and withdrawal of whey from the extended casing.

30. A device according to claim 29, in which the annular element nearer the inlet end of the tubular element is formed as a flange portion of a hollow mandrel on which the casing is supported.

31. A device according to any of claims 26 to 30, including a diaphragm located at the inlet end of the tubular element, the diaphragm having a f low- restricting aperture therein for passage of curdled milk into the tubular element at an enhanced pressure.

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32. A method of preparing cheeses, the method being substantially as hereinbefore described with reference to the drawings.

33. A device for use in the preparation of cheeses, the device being substantially as hereinbefore described with reference to the drawings.

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