FR2502901A2 - Acidulated milk with low mineral content - made by treating fresh milk with cation exchange resin, useful for addn. to milk to form casein coagulate - Google Patents

Abstract

Acidulated decationised milk is claimed having the same protein and lactose content as ordinary milk, but with a very low mineral content of less than 4 g/l, a Ca/P ratio of less than 0.5 and a pH of less than or equal to 3.8. The milk is obtd. e.g. by treating milk at 0-4 deg.C with a cation exchange resin in acid form until the pH of the milk is less than or equal to 3.8, esp. 1.5-3.5. Pref. ion exchange resin is a polystyrene resin carrying sulphonic acid gps., with a gel or macroporous structure. The treatment is carried out e.g. by percolation or in counterflow using a vol. ratio of (pref. skimmed) milk to exchange resin of 5:1 to 15:1. The decationised milk is esp. useful in the prodn. of casein and lactoserum by mixing ordinary milk with an amt. of the decationised milk sufficient to lower the pH of the mixt. to around the isoelectric point of milk casein (4.4-4.6) and heating to 10-60 deg.C to coagulate the casein in the mixt., followed by recovery of the casein and the lactoserum. Process allows rapid prodn. of cheese or curds from milk and avoids drawbacks associated with prodn. of casein by acidulation of milk with exchange resins using prior art processes.

Description

Conventional processes for the manufacture of casein or milk quail for rennet-free cheeses can interfere with the coagulation of catinated casein in milk by lowering the pH of said milk to the isoelectric point of casein which is at pH 4.6. by lactic fermentation of milk, which requires the storage of large volumes of milk throughout the fermentation, which can reach 12 to 16 hours, - either by acidification of the milk by addition of a strong mineral or organic acid (hydrochloric acid, sulfuric acid, lactic acid among others) to lower the pH of said milk to the isoelectric point of the milk casein, at which coagulation of the casein contained in this milk, which leads to a quality casein but also has a large volume of acid whey and strongly mineralized, difficult to develop in the state, and most often requiring additional treatment of demineralization by ion exchange or electrodialysis; moreover, this brutal treatment of milk with a strong acid may distort or degrade certain valuable products contained in the milk to be processed,. or by passing the milk through a cation-exchange resin layer in acid form to replace the cations contained in the milk with hydrogen ions and precipitating milk casein on the particles of said resin, which leads to obtaining quality casein and a whey of good nutritional value,
but the precipitation of casein on the resin particles causes the inactivation of said resin very quickly.

In order to remedy this disadvantage, according to a recent method described in the European patent application published under No. 0004231, it has been proposed to operate in two
steps
- in a first step, we put the milk in contact with
a cation exchange resin to lower the pH of the
milk up to a value greater than the isoelectric point
milk casein, for example at a non-lower pS
at 4.7 and especially between 4.9 and 5, so as to
avoid any flocculation of the milk casein
to cause the imprisonment of the grains of resin échan
by flocculated casein;
in a second step, the milk thus treated is determined.
by adding a dilute acid until a
pH of 4.6, which is the isoelectric point of casein
milk to coagulate this casein that is recovered.

However, the addition in the second stage
acid to acidify the milk, besides
you have a high risk of corrosion for the material of fabri
cation, leads to an acidic whey still strongly
mineralized, requiring for 5a marketing a
total or partial demineralization expensive.

In addition, according to another proposal
written in the French patent application published under the
No. 2,331,963, the skimmed milk is concentrated by ultrafiltra
to obtain a milk concentrate and an ultrafil-
milk (or filtering liquid), then one precipitates
the casein of the milk concentrate by addition of the ultra
filtrate whose pH has been previously lowered by exchange
cations below normal value of 4.3 - 4.8,
for example between 1 and 2.5. The milk concentrate is a
milk enriched with casein and soluble protein (up to
17-19 g per 100 g of milk concentrate against 3 to 3.2 g
per 100 g of normal milk).

The ultrafiltrate of milk contains essentially
the soluble elements of milk, ie lactose,
soluble mineral salts (0.45 - 0.48 g per 100 g
ultrafiltrate), and non-protein nitrogenous substances
(0.12 g - 0.18 g per 100 g ultrafiltrate). It is a "whey" without protein nitrogen compounds.

 Since milk ultrafiltrate does not contain casein or proteinaceous nitrogen substances, there is no precipitation of these materials from the cation exchange resin particles during the treatment of said ultrafiltrate with the resin exchange resin. cations.

 However, the concentration of milk by ultrafiltration requires the implementation of an incubating technique in investments and operating costs to obtain a milk concentrate, which can have the composition of the drained cheese and from which cheese can be prepared. without resorting to the technological stage of draining.

 If, in order to coagulate the casein of the milk concentrate, it was necessary to reintroduce a large quantity of ultracrete of milk (which it was difficult to discard) after lowering its pH by means of an exchange resin. cations, all the benefit that could be expected from the concentration by ultrafiltration would be canceled.

 In addition, the casein yield relative to the weight of liquids (milk concentrate + milk ultrafiltrate) used is small since the volume of liquids used is more than twice the volume of the milk concentrate and that only the milk concentrate contains casein to coagulate.

In the main patent application Ne80.08644
17.4.80, The inventors have found that by
contact of the milk with a cation exchange resin under
acid form, the pH of the milk could be lowered to
Isoelectric point of milk casein (pH 4.6) or
below this isoelectric point without causing the
coagulation of the casein contained in this milk, if one
maintained the milk-resin exchange mixture in a
temperature range from 0 to 40C, while
the ordinary temperature or the average temperatures
high levels, milk casein coagulation takes place as soon as
that the isoelectric point of casein is reached.

In addition, the inventors have also found that by lowering the pH of the milk to a pU less than or equal to 3.8, operating in the temperature range of 0 to 40C and using the cation exchange resins in acid form. a decationized milk is obtained, that is to say largely free of calcium, sodium and potassium cations having a mineral element content of less than 4 g / liter, with a Ca / P ratio of less than 0.5, pH less than or equal to 3.8, that is to say much lower than the isoelectric point of casein
(whereas the pH of normal milk is 6.7.), and containing all the protein nitrogen and lactose materials of normal milk; this decationized milk, acidulated, has the particularity of being able to be kept without precautions
particularly for several days, even if
its temperature has a value greater than 40C, for example
at normal temperature (so it is not necessary
to keep it at 0-4iC) without producing coagu
tion of the casein that it contains, nor any development
microbial.

This milk can advantageously be used
decationized acidulated to acidify in a gentle way the
untreated normal milk and bring the pH of the two milks
at the isoelectric point of milk casein for provo
to coagulate the casein contained in both
in both milk for the purpose of obtaining the
casein and whey, which is an advantage
appreciable economic benefit because the treatment at the
cation exchange resin may be limited to one
only part of the batch of milk intended for the manufacture
casein.

The invention claimed in the main patent application relates to a method of treating milk with a cation exchange resin in acid form, for the preparation of a decationized acidulated milk, without the addition of mineral or organic acid strong; this method comprises contacting the milk with a cation exchange resin in acid form, at a temperature of 0 to 40C, preferably 0 to 2c, for the time necessary to lower the pH of said milk to a lower value or equal to 3.8 i, preferably between 1.5 and 3, j, followed by the separation of the acidified decationized milk obtained from the exchange resin.

 A contact time of 1 to 10 minutes is generally sufficient for the desired pH to be reached; this contact time may be further reduced if the milk and the resin are kept under agitation; the volume ratio of the milk treated with the exchange resin is preferably from 5: 1 to 15: 1.

 As exchange resins, it is possible to use cation exchange resins in acid form, of conventional type, used in clan demineralization, including those used for the demineralization of whey.

 In particular, it is possible to use strongly acid cation exchange resins with a polystyrene backbone bearing sulphonic acid groups, presented in the form of gels or macroporous solids (beads, rods, etc.).

 Macroporous type resins are preferred to gel type resins because of their better mechanical strength.

The strongly acidic cationic resins with polystyrenic backbone containing sulfonic acid groups are marketed under the following brands
"Duolite" from Diaprosim-Diamond
"Amberlite" by Rohm and Haas
"Lowatit" from Bayer
"Kastel" of Montedison
"Dowex" from Dow Chemical
"relite" of Residion
"Zerolit" of Permutit
The strongly acidic cationic resins with the following macroporous structure are preferred
- "Duolite C 26" (styrene-divinylbenzene copolymer with sulfonic acid groups, beads of particle size 0.3 to 1> 2 mm, bulk density 0.85 kg / l).

 "Amberlite 200" and "Amberlite 252" (styrene-divinylbenzene copolymer containing sulfonic acid groups, bulk density 0.80 kg / l, particle size 0.4-0.5 mm).

 "Lewatit SP 112" (polystyrene with sulfonic acid groups, beads of particle size 0.3-1.5 mm, bulk density 0.70-0.80 kg / liter).

 "kastel C 300 P" and "kastel 300 AGRP" (styrene-divinylbenzene copolymer) n sulfonic acid groups, beads having a particle size of 0.3-1.2 mm, bulk density 0.84-0.86 kg / iY.

 "Dowex MSC-" sulfonated styrene-divinylbenzene copolymer; beads with a particle size of 0.29-0.84 mm; apparent density 0.80 kg / l).

 The milk treated with the cation exchange resin is a "decationized" milk (ie containing only traces of calcium, sodium, potassium cations), and acidulated having a pH of less than or equal to 3.8, thus clearly less than the isoelectric point of casein (whereas the pH of ordinary milk is about 6.7), and containing all the protein materials, and lactose of ordinary milk.

 Its mineral content is less than 4 g / l; the Ca / P ratio is less than 0.5 (compared with 1.3 for normal milk).

 The treatment of the milk with the cation exchange resin can be carried out by techniques known per se, either by percolation of the milk through a fixed bed of cation exchange resin, or by the passage of milk countercurrently with the exchange resin. cations, either by mechanical or pneumatic stirring of the milk-resin-exchange-catirone mixture, or by any other suitable method.

 After saturation of the cation exchange resin with the milk cations, the acid exchange resin is re-negated. After rinsing the exchange resin thus regenerated with decationized water, the regenerated exchange resin is protected for a new treatment cycle.

The invention claimed in the main patent application also relates to the use of decationized milk
acidulated with a quantity of untreated normal milk,
sufficient to raise the pH of the mixture to the neighborhood
of the isoelectric point of milk casein, followed by
heating the mixture thus obtained at a temperature of
10 to 60 C, to coagulate the casein contained both
in the treated and untreated milk and
recovers the casein thus coagulated and the lactoserum as well
got.

 More particularly, the decationized acidulated milk is mixed with a certain volume of normal, untreated milk (preferably a volume equal to that of the decationized milk) to raise the pH of the mixture to a pH of 4.4-4.6. heats the mixture thus obtained to a temperature of 40 to 500C to cause the coagulation of the casein contained in said mixture.

 This coagulated casein is separated from the whey and then washed and dried according to the traditional methods (spray drying, or by hot air in a fluidized bed) or converted into caseinates of alkali or alkaline earth metals (sodium, potassium, calcium) or in casein-te ammonium.

 The whey recovered (which contains only the cations provided by the untreated milk) can then be dried in the state or after neutralization or undergo any usual technological operation such as demineralization, ultrafiltration, reverse osmosis concentration.

The lactoserum obtained according to the process described has a low mineralization and the ratios of the different mineral elements, although quite similar to those of the starting milk, have the following particularities:
normal whey whey whey whey
sweet acid according to the in
vention.

Ca # P> 1 # 1 # 1.5 <1
K # P l, 5> 1.5 # 2.5 # 2.0 #P
P 0.85 # 0.6 4 0.3 0.6
It is remarkable that this whey concentrated by ultrafiltration or not has good properties of overreaction and in all cases superior to those of a casein whey obtained by direct acidification and this, as much on the volume after threshing as on the texture.

 The present invention therefore relates to the use of decationized milk claimed in the main patent application for the acidification of normal milk for the preparation of acidified milks or that of cheese curd rennet without rennet and whey.

 The process for preparing the acidified milk according to the present invention comprises mixing the decationized milk with untreated normal milk, in an amount sufficient to bring the pH of the mixture to the desired value.

 The process for preparing the cheese curd without rennet according to the present invention comprises: the mixture of decationized milk acidulated with untreated normal milk in an amount sufficient to raise the pH of the mixture to the vicinity of the isoelectric point of the casein of the milk, heating the mixture thus obtained at a temperature of 10 to 60 ° C to coagulate in the form of curd casein contained both in decationized acidulated milk and in normal milk untreated, -cutting the curd formed, the baking at a temperature between 48 and oOOC, the withdrawal of the whey that is recovered, washing the curd with cold water and then draining thoroughly to obtain drained acid curd.

 More particularly, the acidified decationized milk is mixed with untreated normal milk, previously cooled to a temperature of 0 to 4 ° C., in a sufficient quantity (preferably a volume equal to that of the decationized milk) to raise the pH of the mixture to a value of 4.4-4.8, preferably 4.4-4.6, and then the mixture is heated to a temperature of 30-350C to coagulate the curd.

 It is thus possible to carry out, by the method according to the invention described above, in particular the types of cheeses denominated as follows: "cottage cheese", "queso blanco" (white-American cheese) "quark" (Central European cheese) ), "cheddar-imitation", "ricotta", "blue-cheese" and pizza cheese.

 EXAMPLE: Manufacture of cheeses without presure.

 Preparation of decationized milk.

1000 liters of cooled pasteurized skimmed milk
at 20C are stirred with 100 liters of resin
cation exchange, strongly acidic (H + form)
under the name "Duolite C 26" (copolymer of
sulfonated styrene-divinylbenzene, with a macroporous structure)
in the form of beads of 0.3 to 1.2 mm.
five minutes, the milk is separated from the resin;
with water and regenerated with a 10% hydrochloric acid solution; the decationized milk thus collected is submitted to analysis and has the following composition:
Milk milk composition deca
departureized
Dry matter, g / l 92.5 84.8
Total nitrogen content g / l 34.9 32.2
Casein, g / l 27.3 26.5 Mineral substances g / l 7.9 3.2 pH h, 65 2.4
Calcium, g / l 1.2 0.15
Potassium, gil 1,5 traces
Sodium, 0.45 traces
Chlorides, gil 2.15 1.85 Phosphorus, g / l 1.05 1.0
The decationized milk is characterized by a strongly reduced content of mineral matter and a pB clearly lower than the isoelectric point of milk casein (3.2 g / l of mineral matter against 7.9 g / l for the starting milk; 2.4 vs 6.65 for the starting milk.

 Decationized milk no longer has the white color and opacity of normal milk; it appears as a translucent greenish yellow liquid.

 This decationized milk has no visible sediment after storage for 48 hours at room temperature.

 Preparation of the drained acid curd.

 1000 liters of skimmed pasteurized milk cooled to 20C are mixed with the decantized milk thus collected.

 The pH reaches a value between 4.4 and 5. The mixture is slowly warmed to 320C to coagulate the milk protein materials in the form of a curd.

 As soon as the curd obtained has a suitable firmness, it is cut. The chopped cut is allowed to stand for about 15 minutes and then it is cooked. The quail is heated very slowly to a temperature of between 52 and 550 ° C. and kept at this temperature for about 1 hour until curd presents the desired firmness.

 After withdrawal of the whey, the curd is washed and cooled with chlorinated water (10 mg / liter of free chlorine) acidified to 5.0 fold and then dripped; the washing and draining operations are repeated several times, ending with ice water (between 4 and 50 ° C).

 The quail is again drained in the bottom to remove excess water.

 Preparation of the cheese

 The drained curd may be packaged with or without salt or may be creamed and salted in a manner known per se.

 The resulting product has the texture and taste of traditional "cottage cheese" type cheeses.

Composition of the cheese obtained according to
the invention.

Dry extract.

22 X
Protein8 96.00 Z compared to the extract
dry Mineral materials 2,75 Z ""
Fat 0.75%
Lactose 0.50 Z
Composition of the whey Control whey obtained obtained by the acid acidification method of the invention. hydrochloric,
Dry matter 64.75 g / l 69.30 g / l
Nitrogenous matter 12.57% 12.48% compared to
dry matter
NaCl 2.90 2 6.86 Z
Ash 7.2 Z 11.00 Z
Calcium 1,25 Z 1,82 t
Potassium 1.46% 2.40 Z
Sodium 0.46 Z 0.75 Z
Magnesium 0.13 Z 0.17 Z

Claims (17)

REVENDICATTONS  1. A method of treating milk with a cation exchange resin in acid form, according to one of claims -I to 13 of the main patent application, characterized in that it comprises the following steps a) the contacting the milk with the cation exchange resin in acid form, at a temperature of 0 to 40C. during the time necessary to lower the pH of said milk to a value of less than or equal to 3.8, followed by the separation of the thus obtained decationized milk from the exchange resin, b) the mixing of the decationized milk thus obtained with normal untreated milk in sufficient quantity to bring the pH of the mixture to the desired value. 2. A process for treating ltit by means of a cation exchange resin in acid form, according to one of claims I to 13 of the main patent application, for the preparation of cheese curd acid without rennet and whey, characterized in that it comprises the following steps: a) contacting the milk with the cation exchange resin in acid form, n at a temperature of 0 to 4 ° C, for the time necessary to lower the pH of said milk at a value less than or equal to 3.8, followed by the separation of the decationized milk thus obtained from the exchange resin, b) the mixing of the decationized milk with normal untreated milk, in an amount sufficient to raise the pH of the mixture to the vicinity of the isoelectric point of the milk casein, c) heating the mixture thus obtained to a temperature of 10 to 600C, to coagulate in the form of quail casein contained in both decationized milk acid and in the untreated milk, and (d) the cutting of the curd formed, its cooking at a temperature between 48 and 60 ° C, the withdrawal of the whey and its recovery, the washing of the curd with cold water and the draining thoroughly of said curd. 3. Method according to claim 2, characterized in that the contacting of the milk with the cation exchange resin is carried out for the time necessary to allow the pH of said milk to a pS of 1.5 to 3.5. 4. Process according to claim 2, characterized in that the resin is a strongly acidic cation exchange resin with a polystyrenic backbone carrying sulfonic acid groups, with a gel structure or with a macroporous structure. 5. Method according to claim 2, characterized in that the volume ratio of the milk treated with the exchange resin is 5: 1 to 15: 1. 6. Method according to claim 2, characterized in that the contacting is at a temperature of 0 to 20C. 7; Process according to Claim 2, characterized in that the milk to be treated is skimmed milk. 8. Method according to claim 2, characterized in that the contacting is done with stirring or by percolation, or against the current. 9. Method according to claim 2, characterized in that the untreated normal milk has been previously cooled to a temperature of 0 to 40C. 10. Method according to claim 2 or 3, characterized in that the decationized milk is mixed with a quantity of untreated normal milk, sufficient to raise the pH of the mixture to a value of 4.4 - 4.8. 11. The method of claim 2, 3 or 4, characterized in that the heated mixture of decationized milk and untreated milk at a temperature of 30 to 350C to coagulate the curd. 12. The method of claim 2 or 3, characterized in that the volume ratio between the amount of untreated milk and that of decationized milk is about 1: 1.  13. The method of claim 2 or 3, characterized in that the recovered whey is neutralized with an alkaline or alkaline earth hydroxide, and then concentrated and finally dried. 14. Sour milk curd obtained by the process according to one of claims 2 to 12. Cheese without rennet prepared from the curd according to claim 14. 16. Whey obtained by the process according to one of claims 2 to 13. 17. Acidified milks obtained by the process according to claim 1.