Dairy product and a process for production thereof

Field of the invention

The present invention relates to dairy products, products from sour milk and milk containing products such as drinking milks, raw materials for production of confectionaries or ice creams, baby foods and similarly and a method for production of these products or a method for production of their milk base respectively.

Background of the invention

The general base for production of a dairy product is milk today.

A well known and usual process for production of dairy products, products from sour milk and other milk containing products starts with collection of milk that is than reserved, heated, skimmed, normalized, homogenized, pasteurised, cooled, leavened and in the case of production of products from sour milk also fermented. Then it is filled in, marked and stored for the next processing. The dairy products obtained from the milk processed as mentioned above have on the one hand lower biological value which is given by lower peptide contain in milk and on the other higher price that is given by the price of the starting raw material, i.e. milk.

The aim of this invention is to suggest a preferred dairy product or a milk base respectively for production of dairy products and simultaneously a convenient and effective technology for production of dairy products having higher biological value and the price lower than the products made in usual way.

Summary of the invention

Great deal of the above stated disadvantages of the prior art is removed and the set task is solved by the dairy product or the milk base containing processed milk and/or cream according to the invention the essence of which consists in that the milk and/or cream constitutes one component of a mixture the second component of which is constituted by milk whey demineralized to the demineralization level of 20 to 95% and with an acidity decreased to pH of 5,8 to 7.

It is preferred according to the invention that the starting milk whey used for the demineralization has its dry matter content at most 30%.

According to the invention, such a dairy product or milk base for production milk products respectively is preferred in which the lactose in the whey has been hydrolyzed to the level of 30 to 70%.

For some types of dairy products suggested especially for a specific customer group, it is convenient if the lactose in the milk whey is isomerized to lactulose up to the isomerization level of 10 to 70%.

According to the invention, such a dairy product is preferred in which the whey demineralized by electrodialyzis is mixed with milk and/or cream in the ratio of 1:9 to 9:1. Of course, this dairy product can contain also one or more admixtures of non-milk origin.

The essence of the process for production of the dairy product and/or the milk base for that dairy product, and eventually also the products of sour milk and other milk containing products, in which process the milk raw material is processed by conventional procedures, consists according to the invention in that the milk whey being demineralized by electrodialysis to demineralization level of 20 to 95% and having its acidity decreased to a pH of 5,8 to 7 is used as the milk raw material for production of the milk base or

milk product respectively instead of processed milk and this processed milk whey is mixed with milk and/or cream in a given proportion.

In accordance with the present invention, it is preferred if the milk whey with dry matter content at most 30%, that is advantageously prepared by vacuum evaporation, nanofiltration or reverse osmosis, is used as the milk raw material for the electrodialysis .

Another advantageous solution consists according to the invention in that the lactose in the whey is hydrolyzed up to the level of 30 to 70%.

According to the invention it is profitable if the lactose of the milk whey is lsomerized to lactulose, namely to isomerization level of 10 to 70% before or after the demmeralization .

In the milk contatining products, also other components of non-milk origin can be added to the milk base.

By substitution of the milk base for milk, which milk base being based on the mixture of demmeralized milk whey with milk and/or cream and enriched with whey proteins, dairy products with increased biological value at substantially lower production cost are obtained which expressively increases assortment of these products.

The above mentioned conventional procedure of the milk raw material can include, as generally known, collection, purification, separation, normalization, homogenization, pasteurization and cooling and in products from sour milk also inoculation and fermentation.

Description of particular examples

As the dairy product according to the invention or the milk base respectively for production thereof are advantageously prepared according to just the method of the invention, the description of the product will be combined

with the description of methods of production thereof without darkening the essence of the solution.

The process of production of the dairy product according to the invention is carried out in such a way that the quality of the whey used is tested, the whey is separated out of fat and casein dust, pasteurized, cooled down and reserved. Further, the milk whey demineralization is carried out by means of electrodialysis .

In using concentrated milk whey, the whey concentration is carried out up to the mass portion of dry material at most 30% after reservation, e.g. in an apparatus for vacuum evaporation or by means of an apparatus for reverse osmosis and/or nanofiltration. Only the whey treated in this manner is then processed by means of electrodialysis.

In case the dry whey is used, the regeneration of the whey by means of boiled drinking water cooled to 45 to 50 ⁰ C up to the dry matter portion of 30% is first carried out whereupon filtration and cooling down follow.

The processing of natural or concentrated milk whey by means of electrodialysis is carried out up to the demineralization level in the range of 20 to 95% and active acidity values of the milk whey are adapted to the pH range of 5,8 to 7 in the electrodialysis apparatus. The whey treated in this way is mixed with milk in relation of from 1:9 to 9:1 and according to the fat content it is normalized with cream for the milk base to form. The milk base obtained in this manner is then used for production of various dairy products, products from sour milk and other milk containing products by means of conventional processing technologies for respective particular product.

To obtain products with low lactose content, first the hydrolysis of lactose in the demineralized whey up to the hydrolysis level of 30 to 70% is carried out by a well known

method and only then the whey is mixed with milk in order that the the milk base may be produced.

In order that products with lactulose may be obtained, isomerization of the lactose contained within the whey to lactulose up to the isomerization level of 10 to 70% is carried out by means of one of the well known methods before and/or after the demineralization of the whey.

The determination of the limits of the above mentioned pH range is limited by the fact that, at lower pH values, the mixture of milk whey with milk does not tolerate necessary thermal treatment while at the pH values above the upper limit of the fixed range, the whey protein decomposition occurs which results in generation of unpleasant odour and taste or flavour.

The choice of the milk whey demineralization level follows from the fact that the whey smack or flavour is unsatisfactory due to high salt content at lowering the demineralization level to less than 20% and, at demineralization level higher than 95%, the process is difficult to carry out and, in addition, energy-consuming.

In concentrating or regenerating the dry milk whey before the electrodialysis thereof, the limitation of the dry matter content to not more than 30% is given on the one hand by reduced lactose solubility and on the other by probability of forming lactose crystals in exceeding the limit of 30% of the dry matter content.

As an illustration, the composition of the milk base obtained according to the invention in the form of a mixture of milk and/or cream with demineralized milk whey in comparison with milk is shown in the table below. The dry matter mass fraction in the studied samples was determined by the method of drying up to the steady mass and by refractometry method. The protein mass fraction was determined by Keldahl method and by means of electrophoresis

method and the lactose mass fraction by polarimetry method and by the method of gas-liquid chromatography. The fat mass fraction was determined by the acid method according to Gerber, the mineral substances mass fraction was determined by combustion up to the steady mass and the vitamin mass fraction was determined by chromatography method.

Table

Comparison of milk content with exemplary milk bases according to the invention having the demineralization level of 70%.

* hydrolysis level 70%.

Some preferred examples of compositions and corresponding use of the milk bases according to the present invention are discussed bellow.

Example 1

Milk raw materials are accepted for processing according to the mass and quality. Milk is weighed, mechanical

impurities are removed and, eventually, the milk is reserved, heated and separated. The milk whey is separated for fat and casein powder separation, pasteurized and cooled for short-time reservation. Further, the concentration of the whey up to the dry matter mass portion of 30% is carried out by means of the the above mentioned methods of vacuum distillation, nanofiltration or reverse osmosis followed by cooling, electrodialysis of the concentrated milk whey up to demineralization level of 30% and bringing the active acidity up to the pH value of 5,8 to 7 by means of electrodialysis. Then, the milk base is prepared by mixing the milk being normalized according to its fat content by cream with the demineralized milk whey in the ratio of 9:1. The milk base is homogenized, pasteurized and cooled down. The obtained dairy product, which is drinking milk, can be then dosed into containers, marked and dispatched.

Example 2

The procedure is practically the same as in Example 1 except for the demineralization of the concentrated milk whey realized by electrodialysis that is carried out up to the demineralization level of 60%. The final product is drinking milk again.

Example 3

The procedure is again the same as in Example 1. Only the demineralization level is 90%. The final product is drinking milk again.

Example 4

Also in this case, the drinking milk is prepared similarly to Examples 1 to 3 except of the difference that the electrodialysis of natural milk whey or the concentrated

whey with dry matter content of less than 30% is carried out .

Example 5

The procedure is the same as in Examples 1 to 4 but the milk base is in this case milk normalized according to its fat content by cream and mixed with demineralized milk whey in the ratio of 50:50.

Example 6

The procedure in production of seed yeasts, starters (clabbered milk) and suchlike is again the same as according to Examples 1 to 5. However, the operations of seeding (inoculating), cease fermenting, admixing the ingredients necessary for the technology and following conventional processing to obtain sour milk products are put into the technology process for production of the final product.

Example 7

The procedure is the same as in Example 6 but the milk base consists of milk being normalized according to the fat content with cream and demineralized milk whey mixed together in the ratio of 1:9.

Example 8

To obtain products with low lactose content that are destined for people suffering from lactose deficiency, the precedure is again similar as in Examples 1 to 7. However, the demineralized milk whey lactose is in addition hydrolyzed up to the level of 30 to 70% by means of a well known method.

Example 9

To obtain a functional product with probiotic properties, the procedure is again similar to Examples 1 to

7. Before or after the lactose demineralization, however, the lactose of the milk whey is isomerized by a well known metod to lactulose namely up to the isomerization level of 10 to 70%.

Example 10

One can proceed in the same way as in Examples 1 to 9. To prepare milk containing products, food components of non- milk origin are, however, additionally introduced into the milk base.

Example 11

To obtain milk cans, condensed concentrates or dry products with a long storage life, one can again proceed similarly to Examples 1 to 10. The obtained dairy product, milk containing product or sour milk product is, however, finally concentrated or thickened and/or dehydrated, respectively.

The above described particular examples of the invention are intended only for illustration thereof and not to limit the scope and essence of the invention which is defined in the patent claims.