Method for obtaining high-density quark

Abstract

The invention relates to a method for producing high-density quark, having the following steps: - A producing (100) milk , - B allowing milk (200) to stand, thereby forming curds and a whey fraction, and - C separating (400) the curds (30) from the whey fraction (20), thereby forming a curd fraction (30) with a dry substance content of more than 18%, wherein the separation (400) of the whey fraction (20) and the curds (30) is carried out using a solid-bowl screw-type centrifuge (1).

Description

[0001] PROCESS FOR PRODUCING HIGH-DENSITY QUARK

[0002] The present invention relates to a process for producing high-density quark with a dry matter content of more than 18%. Such products are particularly interesting for the bakery industry, as the product allows for greater variety in the production of cakes and gateaux.

[0003] In Austria, Bulgaria, the Czech Republic, and Hungary, you can also find a quark with a particularly low water content. It is known in Austria as "Bröseltopfen," "Bauerntopfen," or "pressed Topfen" and is used, among other things, to make quark dumplings, cheese dumplings, and Schlutzkrapfen.

[0004] In the world of quark production - ASTA eismann (asta-eismann.de) (Link: https: / / www.asta-eismann.de / de / quark-sauermilch-frischkaese-herstellung.html) - a so-called separator quark is known, which is characterized by its high creaminess. This quark has a dry matter content of typically 18%. The creaminess is technically achieved by the jet discharge of the quark from the centrifugal separator at high pressure. This homogenizes the quark with its liquid components. This makes the otherwise crumbly quark creamy. Technically, the maximum dry matter content in a jet separator is limited.

[0005] Another well-known method is an artisanal version in which whey is pressed from the curd using sterile linen bags.

[0006] An industrial development of this process involves the production of small batches and batch processes using Schulenburg makers (patent DE933367C) or curd makers from ASTA eismann. In the latter case, a basket is pressed into the curd. The whey flows into the basket and is then drained away.

[0007] EP 1 642 494 A1 discloses a process for producing high-density quark as a two-stage process, which is associated with increased mechanical expenditure and which provides a quark with a dry matter content of less than 35%.

[0008] Pseudo-continuous membrane filtration processes are also known, but these have the disadvantage that their product output changes in terms of product composition and technological and / or quality over the processing time. Thus, the shelf life and enjoyment value of a corresponding quark product can be limited by bitterness.

[0009] The use of semi-continuous processes, such as the long, semi-continuous segmented tub systems with mobile cutting units that have been transferred from soft cheese production to the cream cheese sector, produces almost exclusively crumbly products.

[0010] Surprisingly, a jet separator is not suitable for producing high-density curd. Tests have shown that the curd flows out of the separator's solids discharge on a condensate film created by the cooled housing. Conveying it in a pipeline is no longer possible at higher dry masses. The curd sticks to the walls, and forced conveyance is only possible in the center of the pipeline. The adhering film, however, is critical for any potential contamination of the product.

[0011] In addition, so-called separator quark is pressed through the nozzles of a centrifugal separator at approximately 200 bar. This homogenizes the quark, giving it a particularly creamy texture.

[0012] Based on the aforementioned prior art, the object of the present invention is to provide a process for producing a high-density curd, which enables a qualitatively superior product with a high dry matter content due to shortened production times.

[0013] This object is achieved by a method having the features of claim 1.

[0014] A process according to the invention relates to the production of high-density quark. Individual steps in the production of the aforementioned quark and cream cheese are similar. For example, within the scope of the present invention, a cheese curd is also mentioned, which must be separated from the whey. However, the term "cream cheese" refers to a product with a water content in the fat-free cheese mass of more than 73 percent according to German Cheese Regulations. Since the dry matter of the product can exceed this water content, the generic term "quark" (French: "fromage blanc") is used in the present invention.

[0015] The procedure includes the following steps:

[0016] A Providing milk B Curdling milk to form a curd and a whey fraction

[0017] C Separating the curd from the whey fraction to form a curd with a dry matter content of more than 18%.

[0018] According to the invention, the whey fraction and the curd are separated in a single step using a single solid-bowl screw centrifuge. Surprisingly, it has been shown that centrifugal preconcentration of the curd is not necessary.

[0019] By using this well-known device, curds with a high dry matter content of more than 18% can be achieved in this specific application. The quality is superior to products from existing processes due to the short residence time in separation step C.

[0020] Advantageous embodiments of the invention are the subject of the subclaims.

[0021] Preferably, the solid-bowl screw centrifuge can be operated via two motors. These are coordinated in such a way that they each contribute to driving both the bowl and the screw of the solid-bowl screw centrifuge. The power supplied by both motors is thus added together. Preferably, the drive can be configured with a first motor arranged axially to the screw's rotational axis and a second motor arranged parallel to the screw's rotational axis.

[0022] The solid-bowl screw centrifuge can preferably have a device for adjusting the pond depth of the solid-bowl screw centrifuge during operation. This can be, for example, an axially movable throttle disc.

[0023] For further optimized product quality, it is also advantageous if at least the separation in step C, and preferably the entire process, is carried out as a continuous processing step or as a continuous sequence of process steps. Batch processes, such as those typical for quark manufacturers, are therefore not used. The high-density curd produced in step C, which forms the curd, can also advantageously have a particularly high dry matter content of between 20-45%, preferably 25-43%.

[0024] To further improve product quality, at least one product fraction can be blanketed with sterile gas in the solid bowl screw centrifuge, using sterilized air or an inert gas, preferably an inert gas of culinary quality, in particular nitrogen, CO2 or a noble gas, as the sterile gas.

[0025] The average residence time of the curd in the solid bowl screw centrifuge can be less than 10 minutes, preferably 2-8 minutes, at a feed rate of 100 L / h.

[0026] Furthermore, an acidifying agent, preferably a culture, in particular a lactic acid bacteria culture, and / or an inorganic agent and / or another coagulant can be added between steps A and B. This enables a more controlled and time-efficient formation of a cheese curd.

[0027] The same applies if rennet is added between steps A and B.

[0028] At least in individual steps of the process, especially when adding the acidifying agent, pH monitoring can be carried out to monitor the process and improve process control.

[0029] In particular, the acidifying agent can be added in a dosed manner depending on the determined pH value and / or depending on a predetermined production time.

[0030] The milk provided in step A can be vat milk with a preferred fat content of less than 3.0% fat by weight, preferably less than 0.1% fat by weight. A high fat content is not mandatory and may even promote undesirable adhesion to surfaces during production. Therefore, it is advantageous to add fat only after the curd has been isolated.

[0031] After separation in step C, the fat content of the curd can be adjusted by adding additional cream and / or fat until a predetermined target value is reached. Furthermore, the milk can be cauterized, i.e., briefly heated to temperatures above 65°C, before or after acidification and before separation according to step C. This cauterization temperature advantageously prevents syneresis.

[0032] Furthermore, for a constant and even flow, the solids discharge from the solid bowl screw centrifuge can be determined during continuous separation by measuring the flow rate of the whey fraction discharge and the flow rate of the feed line. The whey and curd feed lines can then be adjusted to a desired setpoint for solids discharge.

[0033] The invention is described in more detail below using several embodiments. Identical components are provided with the same reference numerals. The invention is not limited to the embodiments. In particular, individual design features from the embodiments can also be transferred to other embodiments of the invention not shown. They show:

[0034] Fig. 1 Process flow of the process according to the invention;

[0035] Fig. 2 Representation of a solid bowl screw centrifuge used according to the invention with two motor drive and

[0036] Fig. 3 Illustration of a solid bowl screw centrifuge with sterile gas blanket according to a variant of the invention.

[0037] The aim of this process is to produce high-density quark with dry matter contents of more than 18%, particularly between 20.5% and 45%. Dry matter contents between 40% and 43% are considered edible. 45%, on the other hand, represents the maximum technically feasible. According to the invention, this is to be achieved in a continuous production process.

[0038] In a first step 100 of the method according to the invention, milk is provided.

[0039] The milk used can be raw milk, particularly skimmed milk and / or fermented milk. The aforementioned milk can, in particular, be a product obtained by single or multiple milkings of the normal udder secretion of animal species kept for milk production, or a mixture thereof.

[0040] Particularly preferred is skimmed milk and / or standardized milk with a maximum of 3.0% fat by weight, preferably less than 0.1% fat by weight.

[0041] More preferably, unconcentrated skimmed milk with at least 2.8 wt% casein or concentrated skimmed milk between 2.8 wt% and 4.0 wt% casein is used.

[0042] In particular, the milk in the vat can be standardized. Typical standardization involves the targeted adjustment of the milk's fat content.

[0043] Typically, the milk described above is the basis for cream cheese, quark or cream cheese preparations, which, in addition to the standard varieties according to the German Cheese Ordinance, forms the basic material and valuable main ingredient for preparations and foodstuffs.

[0044] This concerns the use as nutritionally and qualitatively high-quality food in the area of ​​ethnic, fusion, novel, snack or other food products.

[0045] The high-density quark products obtained by the process according to the invention differ significantly from industrial intermediates such as casein in their utility and enjoyment value. However, they can be used both as raw materials for commercial applications in bakeries and confectioneries and in catering kitchens, as well as for everyday use as fresh products for non-commercial, private end customers.

[0046] Likewise, comparability with traditionally produced products such as baker's quark (the Austrian equivalent is baker's curd cheese) and their recognizability must lead to market acceptance. This should not only improve yield in the economic sense but also improve sustainability by reducing raw material losses.

[0047] In a second step 200, starter or acidifying cultures are added to the milk. The addition of these cultures converts lactose into lactic acid. Mesophilic and / or thermophilic cultures are preferably used. These are low in gas production and produce EPS (exopolysaccharides).

[0048] Rennet can also be added to the milk, which stimulates the casein to coagulate. However, the addition of rennet is not absolutely necessary for coagulation.

[0049] Step 200, the addition of cultures 11 and / or rennet 12, is optional and advantageously allows for a more targeted acidification of the milk. However, raw milk can also undergo acidification on its own without any control.

[0050] The precipitation of protein in milk, e.g. vat milk, can be achieved in particular physicochemically by adding suitable, approved, animal, vegetable, biotechnologically produced, cultured or inorganic but suitable agents or coagulants or a combination thereof.

[0051] Technologically, the desired textures, product structure, dimensional stability, water binding capacity and permeability should be achieved reproducibly by selecting and dosing the aforementioned additives.

[0052] After acidification, either by adding cultures or by independently forming cultures, sour milk or curdled milk is formed.

[0053] Optionally, there is the option of calcining, i.e., tempering the milk, preferably after acidification, at temperatures higher than the coagulation temperature after acidification. Calcining preferably takes place over a time of less than 2 minutes, preferably between 10 and 30 seconds. The temperature can preferably be between 65 and 80°C. This allows for the denaturation of proteins.

[0054] If the intermediate step of firing is used, cooling can be carried out again to a lower separation temperature, preferably below 25°C, before the solid bowl screw centrifuge.

[0055] The sour milk is then curdled. Step 300 of curdling can be performed through a sequence of resting and stirring, and optionally through temperature changes, such as cooling or heating. The heat input depends, among other things, on the type of cheese or quark being produced—whether it has more hard or soft components. Curdling produces curd and whey. Curdling occurs at a pH of less than 4.6. However, mold and yeast also grow at this pH. Therefore, rapid processing is particularly advantageous for optimal product quality.

[0056] Sensory pH monitoring is carried out when the cultures and / or rennet are added and / or during curdling.

[0057] Particularly preferably, the cultures can be added in doses, with the dosage being determined based on a pre-calculated or desired pre-determined production time. This avoids a pH change at or beyond the isoelectric point.

[0058] In a further step 400, the whey is separated from the curd.

[0059] This is where a special aspect of the present invention comes in. While previously so-called quark makers, such as those from ASTA eismann or Schulenburg, were primarily used to achieve high dry matter contents, the invention uses a solid-bowl screw centrifuge with a horizontally mounted rotation axis to separate the whey.

[0060] It has been shown that when using nozzle separators with a vertical axis of rotation to achieve high-density curd with a dry matter content of greater than or equal to 19%, the drain becomes clogged, which creates a hygienic quality risk.

[0061] A horizontally mounted solid bowl screw centrifuge, also called a decanter, is preferably used for the process. This centrifuge preferably has two motors 2 and 3, a first motor 2 arranged axially to the axis of rotation of the screw 4 and a second motor 3 arranged parallel to the axis of rotation of the screw 4. This second motor 3 can transmit a rotational movement to the screw 4 and the bowl 6 via a gear, in particular a belt drive 5, so that the rotational energy of the first motor 2 is summed with that of the second motor 3. This variant of the drive is known by the applicant as a "summation drive" and is shown in Fig. 2. It has previously been used, for example, for the separation of sewage sludge and has been structurally adapted for use in the food sector in the area of ​​"hygienic design". There are therefore no non-cleanable grooves or gears in the product chamber.Thanks to the intelligent kinematics of this drive system, the power of the two motors is combined and then precisely transmitted to drum 6 and worm 4. Unnecessary conversion losses, which occur with other solutions that require power recirculation, such as backdrives or additional belts, are eliminated with this drive variant. Instead, the differential speed is provided energy-efficiently and seamlessly across a wide range, saving up to 5% in energy compared to other drives.

[0062] Furthermore, the pond depth of the solid-bowl screw centrifuge can be variably adjusted. This is advantageous for adapting the unit's operation to changing conditions, such as the addition of curdled milk from a second tank with a different whey content or curd consistency.

[0063] The variable pond depth setting allows for very quick adaptation of the machine's continuous operation to changed product and / or process parameters.

[0064] The variable pond depth can be positioned in the area of ​​the clarified liquid outlet using an axially movable throttle disc. The throttle disc can be used to determine the gap width of the outlet opening; a smaller gap results in lower whey discharge and thus a higher liquid level. The liquid level and / or the amount of whey discharge can be determined by level and / or flow sensors and adjusted to a preferred range by axially moving the throttle disc.

[0065] The use of the solid bowl screw centrifuge enables efficient clarification of the resulting whey 20, which is reflected in improved yield as well as a continuous and consistently stable discharge of the HD-Quark 30 product as a solid.

[0066] Established processes for further processing HD quark, such as fat-reducing, the production of bars, the production of refined cream cheese, or further blending, extrusion, and / or glazing, can also be facilitated and promoted in advance by the method according to the invention, enabling new / novel, successful products. Preferably, during separation, a sterile gas blanket is applied between the whey 20 and the curd 30, such that the curd is blanketed with sterile gas 50 during the discharge. This is shown in Fig. 3. In the context of the present invention, in addition to sterilized air, an inert gas such as nitrogen or a noble gas can also be considered as a sterile gas.

[0067] Particularly preferably, in a step after separation between the whey and the curd, a cleaning agent is introduced into the solid bowl screw centrifuge for cleaning purposes.

[0068] The setting of the dry matter is preferably determined by the parameter differential speed between the bowl and the screw in the rotor of the solid bowl screw centrifuge.

[0069] A particularly optimized discharge of the separated solids is possible through the above-described preferred drive from two motors with a specific torque over the entire speed range.

[0070] The residence time of the solid to be separated and discharged in the centrifugal field depends on the throughput and the differential speed.

[0071] The drum speed can be varied within a defined, relatively wide range.

[0072] The lower limit of the drum speed is preferably determined by the penetration of centrifugally separated solids, i.e., precipitated protein, into the whey phase to be clarified. The upper limit is determined by the occurrence of syneresis induced by mechanical overload, which leads to an undesirable change in the curd, manifested by a grittiness / gritty product.

[0073] Once the optimal settings for the solid-bowl screw centrifuge have been found in the process, combined with the pretreatment, high-density curd (HD curd) can be produced continuously with the desired dry matter content and quality, as well as with the technological and sensory properties. The dry matter content of curds achievable with jet separators is far exceeded.

[0074] In particular, the HD quark remains pasty and, in particular, pumpable. After the separation of whey and curd into whey and HD quark in the solid-bowl screw centrifuge, a further mixing of cream with the resulting curd can preferably be carried out according to a variant of the inventive process. The goal of the process is initially to achieve a high milk protein and solids content. Fat can also be added after the whey separation, as described.

[0075] In contrast to creamy separator quark, the quark produced by the process according to the invention is rather crumbly, which is particularly desirable in certain applications. One of these applications is use in bakeries for making cakes. Furthermore, increased liquid weights are disruptive during baking. Therefore, dry matter contents above 25% are particularly preferred for HD quark.

[0076] The resulting HD quark has a significantly higher solids content than usual. It also boasts a longer shelf life due to the short processing time.

[0077] Previously known processes typically require several hours for the separation of curds, whereas the present invention achieves the separation of curds into whey and HD curds in less than 10 minutes. This occurs while largely eliminating recontamination risks and providing better control of the much more tightly controlled process.

[0078] Furthermore, the process is characterized by only minimal protein losses. These typically occur due to a shift in the pH value and thus the isoelectric point during longer processing times. The proteins dissolve and drip off with the whey. Residues on and in the sieve mesh of the curd makers commonly used to date lead to additional losses.

[0079] There is also a reduced risk of culture failure in later productions due to a much increased risk of phage proliferation due to aerosol formation and drip whey drying.

[0080] In the continuous process, however, and especially on the steel surfaces of solid-bowl screw centrifuges, very little residue remains. The inflow of curdled milk and the outflow of whey and / or curd are preferably controlled by flow measurement.

[0081] When carrying out the process described above, the speed of the decanter can advantageously be reduced by up to 20% from a maximum speed of 5000 rpm to 4000 and the same throughput.

[0082] Reference symbol

[0083] 1 solid bowl screw centrifuge

[0084] 2 engines

[0085] 3 Engine

[0086] 4 snail

[0087] 5 Belt drive

[0088] 6 drum

[0089] 11 biological cultures e.g. lactic acid cultures

[0090] 12 Lab

[0091] 20 whey

[0092] 30 cheese curds / high-density quark

[0093] 50 sterile gas

[0094] 100 Providing milk

[0095] 200 Addition of starter or acidification cultures (acidification)

[0096] 250 burning

[0097] 300 Curdling the sour milk

[0098] 400 Separating whey from curd

[0099] 500 Remixing of cream and / or fat

Claims

Patent claims 1. A process for producing high-density curd comprising the following steps: A Providing (100) milk; B Curdling (300) of milk to form a curd and a whey fraction; C Separating (400) the curd (30) from the whey fraction (20) to form a curd (30) with a dry matter content of more than 18%. characterized in that the separation (400) of the whey fraction (20) and the curd (30) takes place in a single step by a single solid-bowl screw centrifuge (1).

2. Method according to claim 1, characterized in that the solid bowl screw centrifuge (1) is operated by two motors (2 and 3), preferably with a first motor (2) arranged axially to the axis of rotation of the screw (4) and a second motor (3) arranged parallel to the axis of rotation of the screw (4).

3. Method according to claim 1 or 2, characterized in that the solid bowl screw centrifuge (1) has a device for adjusting the pond depth of the solid bowl screw centrifuge (1) during operation, preferably an axially displaceable throttle disc.

4. Method according to one of the preceding claims, characterized in that at least the separation (400) in step C, and preferably the entire method, takes place as a continuous processing step.

5. Method according to one of the preceding claims, characterized in that the high-density curd provided in step C in the form of curd (30) has a dry matter content of between 20-45%, preferably 25-43%.

6. Method according to one of the preceding claims, characterized in that in the solid bowl screw centrifuge (1) a sterile gas overlay is carried out on at least one product fraction, wherein sterilized air or an inert gas, in particular nitrogen or a noble gas, is used as the sterile gas (50).

7. Method according to one of the preceding claims, characterized in that the residence time of the curd (30) in the solid bowl screw centrifuge (1) is less than 10 minutes at a feed rate of 100 l / h.

8. Method according to one of the preceding claims, characterized in that between steps A and B an addition of an acidifying agent, preferably a culture (11), in particular a lactic acid bacteria culture, and / or an inorganic agent and / or another coagulant takes place.

9. Method according to one of the preceding claims, characterized in that between steps A and B an addition of rennet (12) takes place.

10. Method according to one of the preceding claims, characterized in that pH monitoring is carried out at least in individual steps of the method, in particular during the addition (200) of the acidifying agent. 11 . Method according to one of the preceding claims, characterized in that the addition (200) of the acidifying agent is carried out in a metered manner depending on the determined pH value.

12. Method according to one of the preceding claims, characterized in that the addition (200) of the acidifying agent takes place as a function of a predetermined production time.

13. Process according to one of the preceding claims, characterized in that the milk provided in step A is a skimmed milk with a preferred fat content of less than 3.0% by weight fat, preferably less than 0.1% by weight fat.

14. Method according to one of the preceding claims, characterized in that after the separation (400) in step C, an adjustment (500) of the fat content of the curd is carried out by additional supply of cream and / or fat until a predetermined target value is reached.

15. Method according to one of the preceding claims, characterized in that distillation of the milk takes place before or after the acidification (200) and before the separation (400) according to step C.

16. Method according to one of the preceding claims, characterized in that the solids discharge from the solid bowl screw centrifuge (1) is determined on the basis of a flow measurement of the discharge of the whey fraction and the flow measurement of the feed line.

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