Quark matrix with improved taste characteristics (II)

Abstract

A quark matrix having improved taste characteristics is suggested, which is obtainable by (a) subjecting raw milk to heat treatment, separating the cream, (b) subjecting the skimmed milk such obtained to an ultrafiltration step, a microfiltration step, and/or a reverse osmosis step, producing a high-protein retentate R1 and a high-lactose permeate P1 in the process, (c) enriching the retentate with an amount of lactose which corresponds to the amount that had been separated in the ultrafiltration step as permeate before, (d) subjecting the enrichment product such obtained to heat treatment until denaturation sets in, (e) fermenting the denaturation product such obtained by adding starter cultures and rennet, and (f) adjusting the fermentation product such obtained to defined dry matter and protein contents.

Claims

1. A process for the production of a low-mineral quark matrix, comprising the combination of the following order of steps of: (a) producing a skimmed milk by heat treatment of raw milk, and separation of cream; (b) subjecting the skimmed milk such obtained to an ultrafiltration step, with a membrane having a cut-off of 1,000 to 50,000 Dalton, obtaining a high-protein retentate R1 and a high-lactose permeate P1; (c) enriching the retentate R1 with an amount of lactose which corresponds to an amount separated in the ultrafiltration step as permeate, and which is not the permeate P1 removed in step (b), (d) heat treating an enrichment product such obtained until denaturation sets in, (e) fermenting a denaturation product such obtained by adding starter cultures and rennet, and (f) adjusting a fermentation product thus obtained to defined dry matter and protein content, wherein a quark matrix having both reduced sodium content and improved sensory taste properties being less bitter, less grainy, more fresh, more creamy and softer, is obtained.

2. The process of claim 1, wherein the ultrafiltration is performed using spiral coil modules and/or plate and frame modules.

3. The process of claim 1, wherein the ultrafiltration is performed at a temperature within the range of 10 to 55 C.

4. The process of claim 1, wherein the enrichment product is adjusted to a lactose concentration of about 0.1 to about 3% by weight.

5. The process of claim 1, wherein further additives are added to the enrichment product.

6. The process of claim 1, wherein the enrichment product of the retentate R1 and lactose is subjected to heat treatment at a temperature of 85 to 90 C. for a period of 5 to 10 minutes, and denaturing.

7. The process of claim 1, wherein the cultures and rennet are added to the denaturation product at 25 to 35 C.

8. The process of claim 1, wherein the cultures are one of the two following mixtures 1 or 2: Mixture 1 (i-1) Streptococcus thermophilus, (i-2) Leuconostoc species, (i-3) Lactococcus lactis subsp. lactis biovar diacetylactis, (i-4) Lactococcus lactis subsp. Lactis, and (i-5) Lactococcus lactis subsp. cremoris, and Mixture 2 (ii-1) Streptococcus thermophilus, (ii-2) Lactococcus lactis subsp. lactis, and (ii-3) Lactococcus lactis subsp. cremoris.

9. The process of claim 1, wherein the fermentation product is adjusted to a dry matter content of 15 to 20% by weight and a protein content of 10 to 15% by weight.

10. The process of claim 1, wherein the fermentation product is adjusted by adding a portion of the cream fraction from step (a).

11. The process of claim 1, comprising the additional step of (g) separately processing the permeate P1 obtained in step (b) and which practically contains all short-chain bitter proteins along with lactose.

12. The process of claim 4, wherein the enrichment product is adjusted to a lactose concentration of about 0.5 to about 2.5% by weight.

13. The process of claim 12, wherein the enrichment product is adjusted to a lactose concentration of about 1 to about 2% by weight.

14. The process of claim 1, wherein a quark matrix having a sodium content below 50 ppm is obtained.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The present invention will be described in greater detail with reference to the accompanying drawing which schematically illustrates the process according to the present invention compared to the prior art.

PRODUCTION OF SKIMMED MILK

(2) In order to produce skimmed milk, a separation of non-dairy components and the skimming of the fat content of about 4% by weight from the raw milk is initially performed. This is usually carried out in a special component, preferably a separator. Said components are adequately known from the state of the art. Separators of the company GEA Westfalia Separator GmbH, which allow that these steps may be performed together or individually, are widely used in the dairy industry.sup.1. Corresponding components have also been disclosed, for example, in DE 10036085 C1 (Westfalia) and are perfectly known to one skilled in the art. Therefore, no explanations are needed on how to carry out these process steps, as they are understood to be part of the general specialist knowledge. .sup.1(http://www.westfalia-separator.com/de/anwendungen/molkereitechnik/milch-molke.html).

(3) Heat treatment of the raw milk is preferably carried out in heat exchangers, in which case, specifically, plate heat exchangers have proved to be particularly suitable. There is a temperature gradient at the heat exchangers, which, however, is selected such that the raw milk is heated to a temperature of about 70 to 80 C., and particularly of about 72 to 74 C. for a residence time of a minimum of 20 and a maximum of 60 seconds, preferably about 30 seconds.

(4) Ultrafiltration, Microfiltration, and Reverse Osmosis

(5) In the second process step, the skimmed milk is separated, by means of an ultrafiltration step, into a dairy protein concentrate, which is obtained as retentate, and a dairy permeate.

(6) The term ultrafiltration describes a filtration through membranes having a pore size<0.1 m (1,000 to 50,000 Dalton), while a filtration at pore sizes>0.1 m is usually referred to as microfiltration. In both cases, this concerns purely physical, i.e., mechanical membrane separation methods which apply the principle of mechanical size exclusion: all particles in the fluids which are larger than the membrane pores are retained by the membrane. The driving force in both separation methods is the differential pressure between the inlet and the outlet of the filter area, which is between 0.1 and 10 bar. Depending on the area of application, the filter area material may consist of stainless steel, synthetic material, ceramics or textile fabric. Filter elements appear in different forms: candle filters, flat membranes, spiral coil modules, bag filters and hollow fibre modules, all of which are, in principle, suitable within the meaning of the present invention.

(7) Ultrafiltration is preferably performed at temperatures within the range of about 10 to about 55, preferably about 10 to 20 C., with membranes preferably having an average pore size of 1,000 to about 50,000, more particularly about 5,000 to about 25,000 Dalton. Preferably, the membranes are so-called spiral coil modules or plate and frame modules made of polysulfone or polyethylene membranes.

(8) Reverse osmosis represents an alternative to ultrafiltration. In this process, the skimmed milk is dehydrated using a semi-permeable membrane, increasing the concentration of the valuable dairy proteins as a result. The principle of the process is that the system is subjected to a pressure which must be higher than the pressure created by the osmotic pressure for concentration equilibration. As a result of this, the molecules of the solvent can migrate in the opposite direction to their natural osmotic spreading direction. The pressure forces them into the compartment in which dissolved substances are present in a less concentrated form. Milk has an osmotic pressure of less than 2 bar, the pressure applied for reverse osmosis of milk is 3 to 30 bar, depending on the membrane used and the configuration of the equipment. The osmotic membrane through which only the carrier liquid (solvent) is allowed to pass, retaining the dissolved substances (solutes), must be able to withstand these high pressures. In case the pressure difference more than balances the osmotic gradient, the molecules of the solvent are passing through the membrane just like in a filter, while the milk molecules are retained. In contrast to a classic membrane filter, osmotic membranes do not have through pores. Reverse osmosis is preferably performed at a temperature within the range of 10 to 55, more particularly 10 to 20 C. with semi-permeable membranes having a cut-off of 0 to 1,000 Dalton.

(9) Adjusting the Lactose Content

(10) In the course of ultrafiltration, a retentate is obtained, which contains the valuable long-chain taste-neutral proteins while the permeate contains lactose, salts, and short-chain bitter proteins; these can be treated separately. In order to obtain a pleasantly tasting quark matrix on the basis of the retentate, lactose is added to the same in an amount such that the original lactose content is reached. It is certainly also possible to adjust smaller amounts of lactose if it is intended to obtain low-lactose products. Typically, the retentate is adjusted to a lactose content of about 0.1 to about 3% by weight, preferably about 0.5 to about 2.5% by weight and particularly about 1 to about 2% by weight. If lactose is exchanged for a mixture of glucose and galactose having the same molecular mass, it is possible to produce lactose-free products.

(11) It is also possible to use this process step in order to introduce other substances. Herein, the nature of these other additives is uncritical. Said additives may be other carbohydrates, for example, sugar, but also food additives such as lactoferrin or unsaturated fatty acids may be introduced.

(12) Denaturation

(13) In the following step, the high-protein fraction from the ultrafiltration step, i.e., the retentate, which was enriched with an amount of lactose as described above, is subjected to heat treatment. The denaturation now performed may be carried out by a method known in itself, namely, for a period of about 5 to about 10 min, and preferably about 6 min, and at temperatures of about 85 to about 90 C., more particularly about 88 C.

(14) Fermentation and Standardisation

(15) Also the fermentation of the denatured precursor can be performed according to the known methods of the state of the art. To this end, suitable starter cultures, preferably lactic acid bacteria, and rennet, are added. Suitable starter cultures are particularly probiotic bacteria of the type Bifido bacterium lactis B12 or Lactobacillus acidophilus as well as mesophilic bacteria such as, for example, Lactococcus lactis or Leuconostoc cremoris.

(16) Further, the two following cultures are particularly preferred, which consist of 5 or 3 probiotic bacteria, namely:

(17) Mixture 1

(18) (i-1) Streptococcus thermophilus,

(19) (i-2) Leuconostoc species,

(20) (i-3) Lactococcus lactis subsp. lactis biovar diacetylactis,

(21) (i-4) Lactococcus lactis subsp. lactis, and

(22) (i-5) Lactococcus lactis subsp. cremoris, as well as

(23) Mixture 2

(24) (ii-1) Streptococcus thermophilus,

(25) (ii-2) Lactococcus lactis subsp. lactis, and

(26) (ii-3) Lactococcus lactis subsp. cremoris.

(27) Preferably, the starter cultures contain about 10 to about 90% by weight, preferably about 25 to about 75% by weight and more particularly about 40 to about 60% by weight of mixture (i), and about 90 to about 10% by weight, preferably about 75 to about 25% by weight and more particularly about 60 to about 40% by weight of mixture (ii)
with the proviso that the quantities add up to 100% by weight.

(28) Particularly preferred are starter cultures, containing about 40 to about 60% by weight of mixture (i), and about 60 to about 40% by weight of mixture (ii)
with the proviso that the quantities add up to 100% by weight.

(29) In another preferred embodiment, the five microorganisms forming mixture (i) and the three microorganisms forming mixture (ii) are each contained in about the same quantities. About the same in this context is to be understood as meaning that in mixture (i) the five microorganisms are each contained in quantities of 205% by weight, and in mixture (ii) the three microorganisms are each contained in quantities of 335% by weight. Instead of employing the commercially available preparations (i) and (ii) together, it is, in principle, certainly also possible to use the five microorganisms individually, mixing them such that a mixture of starter cultures is obtained, by means of which the quark products having an improved taste are obtained. Those starter cultures preferably contain about 20 to about 30% by weight Streptococcus thermophilus, about 5 to about 15% by weight Leuconostoc species, about 5 to about 10% by weight Lactococcus lactis subsp. lactis biovar diacetylactis, about 20 to about 30% by weight Lactococcus lactis subsp. lactis, about 20 to about 30% by weight Lactococcus lactis subsp. cremoris, and with the proviso that the quantities add up to 100% by weight.
Particularly preferred are starter cultures, containing 25% by weight Streptococcus thermophilus, 12% by weight Leuconostoc species, 13% by weight Lactococcus lactis subsp. lactis biovar diacetylactis, 25% by weight Lactococcus lactis subsp. lactis, 25% by weight Lactococcus lactis subsp. cremoris

(30) All microorganisms mentioned are commercially available.

(31) The temperature at which fermentation is performed depends on the range of temperature which is optimal for the microorganisms used in each case; typically, the temperature is within the range of about 18 to about 35 C., and preferably at about 30 C.

(32) The quark matrix obtained after fermentation is subsequently adjusted to the desired dry matter and protein contents, for example, by the addition of cream (about the fraction obtained during the production of the skimmed milk). Preferably, the dry matter content is about 15 to about 20% by weight, and more particularly about 18% by weight. The protein content may be about 10 to about 15% by weight, and preferably about 12% by weight.

INDUSTRIAL APPLICABILITY

(33) A further subject matter of the present invention relates to foods, containing the quark matrices according to the invention. This is to be understood as meaning that the matrices themselves represent a component of the food, for example, of a fresh cheese preparation or a quark dish, or are used as an ingredient in the process of the production of the food, for example, in the production of quark (cheese) cake.

EXAMPLES

Comparison Example V1

(34) 4,000 kg skimmed milk were treated at 88 C. for 6 min, denaturing the proteins obtained. Lactic acid bacteria according to mixture (i) and rennet were added to the matrix, which was allowed to ripen at 30 C. for about 18 h and subsequently stirred. Subsequently, the fermentation product was placed into a centrifuge, separating ca. 3.2 kg acid whey as a liquid component. The remaining quark matrix (ca. 800 kg) was adjusted to a fat content of 40% by weight in the dry matter and a protein content of 12% by weight by adding cream.

Comparison Example V2 (Analogous to EP 2796051 A1

(35) 4,000 kg skimmed milk were subjected to an ultrafiltration step using a spiral coil membrane (cut-off 25,000 Dalton) at 20 C. The high-protein retentate was separated, and the permeate was subjected to a nanofiltration step using a spiral coil membrane at 20 C. (cut-off 500 Dalton). Sodium salts and potassium salts were separated along with the permeate. Subsequently, the retentate was treated by adding an aqueous calcium chloride solution that had been adjusted to pH=6 using NaOH, precipitating the phosphates as calcium phosphate. The permeate such obtained was combined with the high-protein retentate from the first step, it was treated at 88 C. for 6 min, denaturing the proteins contained therein. Lactic acid bacteria according to mixture (i) and rennet were added to the matrix, which was stirred at 30 C. for about 2 h. Subsequently, the fermentation product was placed into a centrifuge, separating the acid whey as a liquid component. The remaining quark matrix was adjusted to a fat content of 40% by weight in the dry matter and a protein content of 12% by weight by adding cream.

Example 1

(36) 4,000 kg skimmed milk were subjected to an ultrafiltration step using a spiral coil membrane (cut-off 25,000 Dalton) at 20 C. The high-protein retentate was separated, and the permeate, which contained short-chain bitter proteins along with lactose, was processed separately. The retentate was adjusted to its original content of 2.8% by weight using lactose such that quark was obtained directly after the fermentation step, and the enrichment product such obtained was subsequently treated at 88 C. for 6 min, denaturing the proteins contained therein. Lactic acid bacteria according to mixture (i) and rennet were added to the matrix, which was stirred at 30 C. for about 2 h. Subsequently, the fermentation product was placed into a centrifuge, separating the acid whey as a liquid component. The remaining quark matrix was adjusted to a fat content of 40% by weight in the dry matter and a protein content of 12% by weight by adding cream.

(37) Tasting

(38) The quark matrices were stored in a refrigerator at 10 C. for 24 hours, were subsequently allowed to adapt to environment temperature for 5 minutes, and were then evaluated by 5 assessors for their taste and sensory properties, wherein the scale ranged from (1)=weakly present to (5)=very pronounced. In addition, the sodium content of the products was determined. The results are summarised in Table 1. The average values of the tasting are indicated. Example 1 is according to the invention, examples V1 and V2 are for comparison purposes.

(39) TABLE-US-00001 TABLE 1 Results of the tasting V1 V2 1 Taste evaluation bitter 4.0 2.5 1.0 grainy 4.0 2.5 1.5 fresh 2.0 4.0 4.0 Sensory evaluation creamy 2.5 4.0 4.0 soft 2.5 4.0 4.0 Sodium content Not determined 145 28 [ppm]
In comparison with the closest state of the art, the product according to the invention is not only characterised in that it has a sodium content that is reduced by more than , but it is also perceived to be less bitter and less grainy during the tasting, and tends to be more fresh and more creamy.

(40) In the following, the processes according to examples 1 as well as V1 and V2 are schematically explained in FIG. 1. Here, the abbreviations have the following meaning:

(41) T=Heat treatment (denaturation)

(42) FM=Fermentation

(43) SP=Separation

(44) ST=Standardisation

(45) UF=Ultrafiltration

(46) DM=Demineralisation

(47) MX=Mixing