NL8600922A - Sepg. mineral prods. from milk - by stepwise concn. of whey, with crystallisation and sepn. of minerals and later of lactose - Google Patents

Abstract

Prods. rich in minerals are obtd. from milk by (a) concentrating whey to a dry matter content in which the lactose is not yet super-satd. but mineral components may be super-satd., (b) opt. promoting crystallisation of minerals by addn. of substances which reinforce the super-satn. and/or initiate and promote crystal growth, allowing crystall-isation to proceed, and sepg. the crystals formed, (c) concentrating the cleared liq. further until the lactose can crystallise out and sepg. the crystallised lactose, (d) de-salting the liq., poor in lactose, by electrodialysis, opt. combined with treatment with an ion-exchanger, (e) opt. adding to the liq., lean in salt and lactose, substances which promote the super-satn. and/or crystallisation of minerals, and sepg. the crystallised components, after which the cleared liq. can be processed in the normal way to whey prods. low in minerals and lactose and (f) mixing the crystals obtd. in (b) the crystallised components obtd. in (e), and the soln. of minerals obtd. in (d), and drying the mixt, or using it in liq. form.

Description

-1- VO 8158

METHOD FOR EXTRACTING MINERAL-Rich PRODUCTS FROM MILK

The invention relates to a method for preparing mineral-rich products from milk. In addition to proteins, milk fat and milk sugar, milk naturally also has a content of mineral constituents that are tailored to the needs of young mammals. When the milk itself is consumed, this balanced diet is taken in as a whole. But milk is also used as a raw material for products such as cheese and the like, where these minerals are partly or wholly in the. whey ends up.

Usually, this whey can be used as a raw material for foodstuffs, but in that case the enrichment of minerals in that whey is not always desirable, for instance in the preparation of baby food. It is usual in such cases to desalinate whey to a greater or lesser extent. The separated mineral constituents are then regarded as waste and, in particular if they are obtained in the form of a dilute acidic or alkaline solution, may give rise to environmental problems.

For the preparation of new foods and dietary products, there is a need for mineral-rich products that come as close as possible to the balanced composition of milk. It is of course possible to add such minerals to a foodstuff in the form of a synthetic mixture of salts, but a milk-based mixture is certainly as attractive to the consumer. If such a mineral-rich product is obtained, '*' Λ .v *

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In general, this results in the problem that both electrodialysis and ion exchange produce dilute solutions, whether or not mixed with added acids, bases or salts, from the waste products obtained from the desalination of whey, so that concentrating and purifying such by-products makes the recovery of mineral-rich products from milk economically unattractive.

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It has now been found that one can avoid this last drawback if one successively: a. Concentrates whey to a dry matter content in which the milk sugar present is not yet supersaturated and mineral constituents present can become supersaturated, 15 b. optionally promotes crystallization of mineral constituents by adding substances which enhance supersaturation and / or initiate and promote crystal growth and allow crystallization to proceed and the formed crystals to separate, c. . further concentrates the clarified liquid until the milk sugar can crystallize out and then separates the crystallized milk sugar, -3- d. the low-sugar liquid by means of electrodialysis, optionally combined with treatment with ion exchangers, desalted, 5 e. add the supersaturation and / or the crystallization of mineral constituents, if appropriate, to the salt and milk sugar-low liquid thus obtained, and then the crystallized constituents are separated, and the clarified liquid is subsequently processed into mineral and milk-sugar whey products in the usual manner , f. the bee b. crystals obtained, the at e. crystallized constituents obtained and the d. the obtained mineral solution and the resulting mixture is dried or used in a liquid form.

An advantage of this method is that by separating a considerable part of the mineral constituents from the milk by crystallization, the minerals are obtained in a considerably more concentrated 2U form than in the case that all minerals are obtained in the usual manner by electrodialysis or ion exchange. extracts whey.

Accordingly, less also needs to be done to reduce the water content in the final product obtained to a concentration desired for use. For example, if one wishes to enrich a dry powdered product with milk minerals, then all the moisture present will have to be removed by drying, but liquid concentrates can also be used for a liquid imitation milk or a cosmetic liquid.

A complication here is the fact that in all processes that yield whey as a product, the mineral composition in the whey corresponds to that of milk. In particular, in the curdling of milk for the production of cheese, a considerable part of the minerals in the form of calcium phosphates disappears from the whey because it remains enclosed in the cheese curd. If the method is therefore applied to so-called sweet cheese whey or products of comparable origin, for example whey obtained after preparation of rennet casein, it is preferable to add to the mixture of minerals an amount of calcium phosphate which corresponds to the amount of calcium phosphate which is the cheese preparation has been separated from the whey. Likewise, the natural mineral ratio of milk is disturbed if casein curd is separated from milk by addition of a mineral acid such as sulfuric acid and the casein whey obtained serves as raw material for the extraction of milk minerals. In that case, the disturbed balance can be restored by replacing the b. add crystals of calcium phosphate obtained to the mixture in an amount corresponding to the calcium removed in b. crystal obtained. Methods in which milk is directly inhibited by contacting ion exchangers in the hydrogen form or by mixing with whey which has been acidified by ion exchange is described as, for example, in Patent Applications 6600767 or 7411060, whey with a mineral composition modified with respect to the cations . This deviation can be corrected by adding, in step b, a mixture of hydroxides such that a neutral whey with the same cation composition as milk is obtained.

If whey is obtained by acidifying milk by microbiological means and separating the curd, one can obtain a raw material which, in terms of the mineral composition, need hardly differ from that of milk. Therefore, no additives or replacements with milk-foreign minerals are necessary. In that case, however, the milk sugar content is reduced by conversion to lactic acid. This not only reduces the yield of milk sugar, but also influences the composition of the mineral fractions that are used in b., E. and f. be obtained. Whey obtained via the electrolysis effected acidification of milk, combined with a simultaneous neutralization of the whey obtained, as described in Dutch patent application 8102826, yields a product which has very favorable properties as a raw material for preparing a milk mineral product.

For the separation of the crystallized mineral constituents in steps b. and e. one can use conventional separation techniques such as filtration, centrifugation and the like. Since it is important here how the dimensions of the crystals to be separated are and to what extent the substances in question can be crystallized, it is recommended to favor crystallization by ensuring an appropriate degree of supersaturation. This can be achieved in the first place by an appropriate choice of concentration and temperature, and in addition, the solubility product of the substances concerned, such as calcium phosphate, calcium sulfate, calcium citrate and the like, can also be influenced by the addition of pH-regulating agents. * Depending on the type of whey and the associated mineral composition, in some cases a more separable crystal will be obtained by lowering the pH with acids such as phosphoric, sulfuric or citric acid, while in other cases increasing the pH by adding calcium hydroxide, or ammonium hydroxide, if one does not wish to disturb the mineral balance, gives the desired effect on the crystallization.

It is also useful to initiate crystallization by already adding a certain amount of the desired compound in an appropriate fineness after the liquid has reached the desired degree of supersaturation by concentration and cooling. It is thereby achieved that the balance between the various mineral constituents is not disturbed when an amount of crystal obtained from a previous batch of whey is used for this crystal seed material, after an appropriate method of cleaning and size reduction. one can extract minerals from one batch of whey in a corresponding manner and use it in the processing of another batch of whey in order to improve the balance of the various minerals. Thus, for example, a calcium phosphate-rich product can be recovered from sour whey and used to make up for the lack thereof in a product based on sweet cheese whey or whey obtained by acidification with mineral acids, whereby at b. formed crystal does not have the desired composition.

It is of course important that in the crystallization of mineral components in steps b. and e. as few compounds as possible, other than minerals, are present in such a form that they interfere with the crystallization by insolubility, or that on step c. also the whey proteins remain in soluble form during concentration and that the crystallization of the milk sugar and its separation is as good and complete as possible. The manner in which this recovery of milk sugar can proceed is generally known, for instance from Dutch published patent application 132095, in which it is described that adjusting the pH to 3.6-3.8 is important in connection with the solubility of proteins. But also when desalting step d. and thereafter damage to the protein should be avoided as much as possible, so that all three products which can be obtained in the invented method, namely a milk-mineral mixture, milk sugar and low-sugar desalinated whey powder, in the most favorable possible form.

The invention is further illustrated by the following examples:

Example 1

Acid casein whey with pH 4.5, obtained after microbiological acidification of milk and recovery of acid casein, was concentrated to 22% dry matter by evaporation. Using ammonia, the acidity was reduced to pH 6.0 and the whey was stored at a temperature of 45 ° C for 1 hour with slow stirring. The crystallized material was separated by a centrifuge.

The centrifuged whey was further concentrated to 62¾ dry matter and cooled to 30 ° C with slow stirring. The crystallized milk sugar was separated by centrifuges and further processed.

The desugared whey was desalted by electrodialysis.

The desalinated liquid was adjusted to pH 7.5 with NaOH and kept at 45 ° C for 1 hour with slow stirring. The crystalline material formed was separated by centrifugation.

The latter crystalline material and the material separated from the whey concentrated to 22¾ was suspended in the reverse osmosis concentrated salt-rich liquid, which was obtained by electrodialysis and the mixture was dried.

Example 2

Sweet cheese whey, obtained after the preparation of Gouda cheese, with a pH of 6.5 was concentrated by evaporation to 26¾ dry matter. The whey was left for 1 hour. stored under slow stirring at a temperature of 45 ° C. The crystallized material was separated by a centrifuge. In a similar manner as in Example 1, the clarified whey was further processed to give successively milk sugar, desugared, desalinated whey and a salt solution obtained by electrodialysis plus an amount of crystalline mineral constituents.

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To the mixture of this salt solution and both crystal masses obtained by centrifugation, so much tricalcium phosphate was added that the obtained mineral mixture obtained a calcium content of 15¾ on dry matter.

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Example 5

Acid casein whey, obtained after recovering acid casein by acidifying milk with sulfuric acid, at pH 4.0, was concentrated to 30% dry matter by evaporation. The whey was stored under slow stirring at a temperature of 45 ° C for 1 hour. The crystallized material was separated by centrifuge and discarded after washing.

The clarified whey was concentrated to a product with 60-62¾ dry matter and a pH of 3.6-3.8, after which the milk sugar crystallized and separated. In a similar manner as in Examples 1 and 2, the desugared whey salt became, with a by-product a mixture of the salt solution obtained by desalination, and the crystalline mass recovered by crystallization and centrifugation. To compensate for the previously separated and discarded crystalline material, 0.6 grams of tricalcium phosphate was added to the above-mentioned salt solution per gram of dry matter in the discarded material.

-10-

Example 4

As in Example 3, a crystallized material was separated from acid casein whey, which was washed. 20 of this washed material was added to a subsequent batch of whey of the same size as the first batch, in order to accelerate the crystallization, so that the crystal could be separated again after a shorter crystallization time. The further processing was carried out as in Example 3, with the difference that the amount of tricalcium phosphate added as compensation was calculated on the difference between added and subsequently separated and discarded material.

Example 3 15

Casein whey was acidified by ion exchange with an acid-charged cation exchanger, after which this whey was mixed with milk until a pH of 4.5 was reached in the mixture and the casein could be separated as curd. Part of the whey was then acidified again with ion exchangers, the rest concentrated to 22¾ dry matter. The concentrate was adjusted to pH 6.0 with a mixture of potassium, sodium and calcium hydroxide in the ratio as the ions in milk existed and the whey was further treated as in Example 1.

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Pre-loaded 6 #

A mineral mixture as described in Example 1 was added to a solution of soy protein in water. In this solution 5, a mixture of vegetable fats and monoglyceride emulsifiers was emulsified using a homogenizer and the emulsion was dried in a spray dryer. Such a milk substitute can serve, for example, for people with cow's milk allergy as a coffee whitener, since it shows good dissolving properties and whitening power. The nutritional value can be increased at will by supplementing vitamins and other important components of milk during preparation.

Claims (7)

1. Process for the extraction of mineral-rich products from milk, characterized in that one successively concentrates: a. Whey to a dry matter content in which the milk sugar present is not yet supersaturated and mineral components present may become supersaturated, b. optionally promotes crystallization of mineral constituents by adding substances which enhance supersaturation and / or initiate and promote crystal growth and allow crystallization to proceed and the formed crystal to be separated, c. further concentrating the clarified liquid until the milk sugar can crystallize and then separates the crystallized milk sugar, d. the milk-sugar-reduced liquid by means of electrodialysis, whether or not combined with a treatment with ion exchangers, desalinated, -13- _ -r = · - - - * e. add the supersaturation and / or the crystallization of mineral constituents, if appropriate, to the salt and milk sugar-poor liquid thus obtained, and then the crystallized constituents are separated off, after which the clarified liquid is processed in a usual manner to mineral and low-whey whey products, f. the bee b. crystals obtained, the at e. crystallized constituents obtained and the d. the obtained mineral solution and the resulting mixture is dried or used in liquid form. 2. A method according to claim 1, characterized in that whey obtained is obtained by acidification of milk by microbiological means or by electrolysis and by subsequently separating the curd, whereby steps b. and e. does not add any substances other than minerals from milk or whey. 20 Method according to claim 1, characterized in that cheese whey is started from and subsequently added to f. obtained mixture adds an amount of calcium phosphate which corresponds to the amount of calcium phosphate which ends up in the cheese during cheese preparation. -14- 4. Process according to claim 1, characterized in that whey is obtained from acidification of milk with mineral acids and separation of the curd, and that instead of bee b. crystals separated, a corresponding amount of calcium phosphate to the f. listed mineral mixture. 5. Process according to claim 1, characterized in that whey obtained by acidification of 'milk by means of ion exchange applied to the milk or on whey' which is subsequently mixed with the milk is started from, and subsequently in step b. adds such a mixture of hydroxides that a neutral whey with the same cation composition as milk is obtained. 15 6. Process according to claim 1, characterized in that a batch of whey is concentrated to a dry matter content, in which the milk sugar present is not yet supersaturated and mineral elements present may become supersaturated, optionally promoting crystallization by adding substances which supersaturate and / or initiate and promote crystal growth and that the crystallization is allowed to proceed and the crystal formed is separated and then this crystal is used after a possible further cleaning in another batch of whey as a substance which, as stated under b », initiates the crystal growth and promotes. -15- 7. Process according to claim 1, characterized in that a batch of whey is concentrated to a dry matter content in which the milk sugar present is not yet supersaturated and mineral elements present may become supersaturated, optionally promoting crystallization by adding substances which enhance the supersaturation and / or initiate and promote crystal growth and allow the crystallization to proceed and the crystal formed to be separated and then, after any further cleaning, this crystal is used in a different batch of whey to add it to f. obtained mineral mixture.