FR2470546A1 - Cheese prodn. - using ultrafiltration permeate for acidification after cation removal, of the milk - Google Patents

Abstract

Prodn. of cheese comprises ultrafiltration of milk, of reduced pH to give a retentate which, opt. after adding other milk components such as cream, is thickened or coagulated, then processed conventionally to cheese. Novelty is that the permeate from ultrafiltration is acidified by cation removal (pref. to pH 1-2) and then used for reducing pH of the milk. Pref. the milk is acidified to between pH 6 and the coagulation point of casein. Opt. only a portion of the permeate is acidified, then added to untreated permeate to give the required final pH. Ultrafiltration is pref. controlled to give vol. ratio permeate:retentate of 1.5-3:1. Process does not require additional, non-milk acids or fermentative pre-ripening. It is easily controlled to give the required characteristics (taste and consistency) of a wide range of cheese types. Both the milk used for cheese making and the permeate may be used in conc. form. Acidification is esp. by treatment with a cation exchanger or by electrodialysis.

Description

 Process for the preparation of cheese.

 The invention relates to a method for preparing cheese by ultrafiltration of cheese milk and transformation of the fraction retained at ultrafiltration into the desired cheese.

 The use of the fraction retained on ultrafiltration of cheese milk for the preparation of cheese is known. We usually start with an ultra-filtered skimmed milk which is then brought back to the desired fat content by adding concentrated cream. The fraction retained at the ultrafiltration is then transformed into cheese in the usual manner, but with a lower extraction of the whey, depending on the degree of protein enrichment, we obtain in the final product a higher proportion of proteins from the small milk.

However, this known process has a drawback: difficulties are encountered with regard to the consistency of the final product. Fresh cheese is often floury, soft cheeses exhibit variable, hardly predictable, ripening behaviors and deviations from the taste and consistency typical in each case for the type of cheese. It is assumed that this must be attributed to the influence of calcium ~ which, in this process, cannot be eliminated with whey nor, either, with the ultrafiltrate, because it is enriched with the proteins in the fraction retained at ultrafiltration.

 Attempts have already been made to remedy these difficulties by subjecting the cheese milk to prior maturation by fermentation with the addition of cultures of lactic acid. In this operation, the normal nH of milk which is from 6.6 to 6.7 is lowered to values of about 6 or below.

This prior maturation is pronounced for a fraction retained at the ultrafiltration and semi-concentrated so that later, during the thickening, there still flows whey, or else performs even before the ultrafiltration (patent applications RFA published before examination
DE-OS 2.734.825 and 2.343.333). This prior maturation by fermentation however causes contamination of the cheese milk with microorganisms. In addition, the end point of this type of acidification is difficult to control, just as it is practically impossible to keep the pH value constant during ultrafiltration, due to the continuation of fermentation. Finally, this prior maturation requires a large storage capacity.

 To extract part of the calcium contained in cheese milk, acids such as phosphoric acid, hydrochloric acid, lactic acid and the like were also added to the latter before ultrafiltration, in order to that part of the calcium goes to ultrafiltration.

However, this process has the disadvantage of requiring the addition of foreign substances, which are often illegal.

 Consequently, and in order to avoid the use of foreign substances, acid whey was added to the milk.

This way of operating encounters difficulties because in an installation in which cheese is prepared by passing through ultrafiltration without extraction of whey, there is practically no more of the latter. So you have to buy whey or get it through a production line that has nothing to do with the preparation of the cheese itself. As a result, such a whey, if not pasteurized or sterilized, is contaminated with foreign bacteria for ripening and again causes difficulties in the ripening process. In addition, whey generally contains fine parts (casein particles from the previous precipitation operation or denatured whey troteins) which interfere with ultrafiltration operations. The organoleptic qualities of a whey transported or stored for long periods of time is also less good than that of whey taken fresh from the production line.

 The Applicant then sought to remedy the drawbacks described above of the prior methods. In particular, it sought to avoid the addition of foreign acids or prior maturation by fermentation, it sought to make the process well controllable and to achieve in particular the typical consistency and taste properties of the type of cheese to be prepared. .

Other objects and advantages of the invention will appear on reading the description below.

These aims and advantages have been achieved in a process for the preparation of cheeses by ultrafiltration of a cheese milk whose pH has been lowered, with the formation of a fraction retained on ultrafiltration which, if necessary, after addition of other constituents of milk such as the cream, are thickened or coagulated, then transformed into cheese in the usual manner, this process being characterized in that the ultrafiltrate is acidified by elimination of cations and then added to cheese milk to lower the DH.

It was surprisingly found that the ultrafiltrates of milk or cream, added to cheese milk, did not affect the course of the ultrafiltration or the ripening process of the cheese.

The cheese milks that are used according to the invention are milk adjusted to the desired fat content, skim milk, and concentrated milks of the two types.

The acidifying agents are all the ultrafiltrates obtained in cheese making, in particular those obtained at the ultrafiltration of cheese milk for soft cheeses and fresh cheeses, after acidification by elimination of cations, as well as the concentrates of these ultrafiltrates and cutting fluids obtained from ultrafiltrates at various pH.

 The acidification of dairy products by elimination of cations is known and will therefore not be described in more detail below. Preferably, the cations are removed using cation exchangers. However, the electrodialysis technique can also be used alone or in combination with the cation exchange technique. However, this known acidification method did not make it possible to foresee that the acidification agent used in accordance with the invention would in particular make it possible to eliminate the problems encountered in the behavior at ripening or with regard to taste and taste. consistency of the final product in the transformation of the fractions selected for ultrafiltration into cheese.

 Preferably, in carrying out the method according to the invention, the cheese milk is brought to a pH of less than 6 and, under the best conditions, to a pH between the casein coagulation point and pH 6.

 The elimination of the cations in the ultrafiltrate is advantageously carried out so as to reach a pH between 1 and 2. To better control the operation, the acidified ultrafiltrate can be cut to the pH indicated with the initial ultrafiltrate and add the acid cleavage obtained under these conditions from cheese milk in the quantity desired to reach the desired pH. This possibility of variation makes it possible to make the process according to the invention particularly adaptable and to adjust to any desired combination of pH and composition the substances introduced into the cheese milk with the acidified ultrafiltrate, in particular lactose, salts and milk acids. The ultrafiltrate used for acidification can also be used in concentrated form, the concentration being carried out before or after the elimination of the cations.

The cheese milk can itself be used in the process according to the invention in a form already concentrated beforehand. In this respect, it has proved particularly advantageous to use according to the invention an ultrafiltrate which has been obtained by continuing the ultrafiltration to a volume ratio of 1.5: 1 to 3: 1 between 1 ultrafiltrate and the fraction retained.

The table below shows the quantities of acidifying liquid, in liters, necessary to adjust 100 liters of cheese milk to a desired pH. The results reported in the table show that, depending on the desired pH for the cheese milk and the ultrafiltrate treated by cation exchange which is used for acidification, it is possible to achieve an extremely wide variation in the quantities to be mixed.

BOARD
Quantities of acidifying liquid, in liters, necessary to adjust 100 liters of cheese milk to a desired pH.

Cheese milk Ultrafiltrate treated by exchange
of cations
initial pH final pH pH 1.2 pH 1.7 pH 3.0
6.6 6.4 2.8 5.4 10.0
6.2 5.4 9.3 20.0
6.0 8.0 14.0 34.0
5.8 11.5 21.0 50.0
5.6 15.7 27.5 70.0
The process according to the invention is particularly suitable for the preparation of soft cheeses, fresh cheeses and all types of cheeses which, before thickening, require acidification of the cheese milk, such as "Cheddar" cheese, various types of hard cheese, mozzarella, pasta filata and similar cheeses.

The method according to the invention brings many advantages. Thus, prior maturation by fermentation is avoided, having the drawbacks described above, the addition of foreign acids is also avoided. The acids contained in the acidifying agent are not only natural constituents of milk, but also come from the milk itself used for the preparation of cheese. The ultrafiltrate can be used rationally. It is also possible to reduce the energy requirements for the overall operation of the milk and of the ultrafiltration by suitably combining the operations of evaporation and ultrafiltration.

The lactose in the ultrafiltrate does not undergo any degradation, even partial, because it is no longer exposed to prior fermentation. It can be isolated in a subsequent operation or treated for example by enzymatic hydrolysis and be used optimally.

Relatively small quantities of acidifying agent are required, so that the relative proportions of the constituents of cheese milk are only slightly modified.

The acidification capacity of the ultrafiltrate is also exploited under optimal conditions.

It is also possible to send the ultrafiltrates to the ion exchangers at concentrations higher than those which are possible with whey, since there is no "contamination" by the proteins. The result is not only an increase in the acidification capacity of the ultrafiltrate, but also a reduction in the need for reservoirs.

The following examples illustrate the invention without, however, limiting its scope, in these examples, the indications of parts and of% are by weight, unless otherwise stated.

EXAMPLE 1 (comparative).

 From 1,000 liters of skimmed and pasteurized milk, a 15% dry matter concentrate is prepared by ultrafiltration. This concentrate is adjusted in the usual way, using 40% fat cream, to a fat content such that the final product has the total fat content (45% fat on dry matter ). The "superfatted" concentrate is added with an acidification culture to the usual quantity for the prior maturation of the cheese milk in the preparation of the camembert and stored for several hours, until the pH reaches the value of 5.9. This pre-matured concentrate is curdled in the usual way by the addition of specific mold cultures and rennet and transformed into camembert.

EXAMPLE 2 (according to the invention).

To 1,000 liters of skimmed and pasteurized milk, 180 liters of an ultrafiltrate of skimmed milk are added, brought to pH 1.7 by cation exchange. The pH of the milk is thus lowered to 5.9. This milk is transformed by ultrafiltration as described in Example 1 into a concentrate at 15% dry matter. The concentrate is brought to the standard fat content, as described in Example 1, with the same amount of 40% cream and transformed into camembert in the usual way, by adding rennet and specific cultures.

By its consistency and taste, the cheese is analogous to that of Example 10 However, compared with this, it is particularly distinguished by a regular structure and a regular taste from one manufacture to another.
EXAMPLE 3 (comparative).

From 1,000 liters of skimmed milk, a concentrate is formed by ultrafiltration which corresponds, by its protein content (and taking into account the amount of cream that will be added) to the cheese to be prepared. fat on dry matter with 40% cream and then curdled by addition of an acid culture, a specific culture for camembert and rennet Apyres finishing, the cheeses have a slightly chalky taste which cannot be compared to taste of a Camembert prepared in the usual way.

EXAMPLE 4 (comparative)
To 1,000 liters of pasteurized and skimmed milk, small quantities of acid culture are added and subjected to prior maturation for a few hours, the pH drops to 6.1. This milk is concentrated by ultrafiltration until its protein content (taking into account the quantity of cream which remains to be added) corresponds to that of the cheese to be prepared. During the ultrafiltration, the pH drops by 1 to 2 tenths: The concentrate is adjusted to a fat content of 45% on dry matter, using 40% cream. It is then curdled by the addition of specific cultures and coagulating enzymes and it is transformed directly into camembert, without eliminating whey.

EXAMPLE 5 (according to the invention).

 To 1,000 liters of pasteurized and skimmed milk, 180 ml of skimmed milk ultrafiltrate brought to pH 1.7 by cation exchange are added as described in Example 2, this addition causes the pH of the milk to drop to 5.9 .

By operating as described in Example 4, this milk is then subjected to ultrafiltration. During this, the pH remains constant. The concentrate is adjusted to 45% fat on dry matter using cream and transformed into camembert as described in Example 4.

 By their consistency and taste, the cheeses obtained are at least equivalent to those of Example 4; but they are clearly superior as regards uniformity from one manufacturing to another.

EXAMPLE 6 (preparation according to the invention of fresh cheeses).

To 1,000 liters of skimmed and pasteurized milk, 275 liters of skimmed milk ultrafiltrate, brought to pH 1.7, are added, by cation exchange, this addition lowers the pH of the milk to 5.6. This milk is subjected to an ultrafiltration as described in Example 3 and concentrated until the protein content, taking into account the amount of cream to be added later, corresponds to that of the fresh cheese to be prepared. During the ultrafiltration, the pH remains constant. The fraction retained at the ultrafiltration is "superfat" with the help of cream and then transformed by fermentative coagulation without eliminating whey in fresh cheese.

This fresh cheese has a remarkable soft consistency.

 As goes without saying, and as it already follows from the above, the invention is in no way limited to those of its embodiments and of application which have been more especially envisaged; on the contrary, it embraces all its variants.

Claims (8)

 1. Process for the preparation of cheese by ultrafiltration of a cheese milk whose pH has been lowered, with the formation of a fraction retained on ultrafiltration which, if necessary after addition of other constituents of the milk, such as the cream is thickened or coagulated and then transformed into cheese in the usual way, characterized in that the ultrafiltrate obtained is acidified by elimination of cations and added to the cheese milk to lower the pH. 2. Method according to claim 1, characterized in that the cheese milk is adjusted to a pH below 6.  3. Method according to claim 2, characterized in that the pH of the cheese milk is adjusted to a pH between the coagulation point of casein and pH 6.  4. Method according to any one of claims 1 to 3, characterized in that the ultrafiltrate is adjusted by elimination of the cations at a pH of 1 to 2.  5. Method according to claim 4, characterized in that a portion of the ultrafiltrate is brought to a pH between 1 and 2, it is adjusted to the desired final pH by cutting with the initial ultrafiltrate and the mixture is added to cheese milk to acidify it. 6. Method according to any one of claims 1 to 5, characterized in that the ultrafiltrate used for acidification is concentrated before or after the elimination of the cations and used in concentrated form. 7. Method according to any one of claims 1 to 6, characterized in that the cheese milk is used in the concentrated state.  8. Method according to any one of claims 1 to 7, characterized in that the ultrafiltration is continued until a volume ratio of 1.5: 1 to 3: 1 between the ultrafiltrate and the fraction retained ultrafiltration.