METHOD FOR PRODUCING A COLD MILK MIXED DRINK

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for producing a cold mixed drink from milk and an acidic component. DESCRIPTION

[0002] Cold milk drinks have been available on the market for some time. Such drinks often contain additives such as stabilizers, emulsifiers, acidity regulators, and / or binding agents. These additives are intended to stabilize the consistency and properties of a milk drink. Acidity regulators are used, for example, in the production of a mixture of milk and an acidic ingredient to prevent coagulation during production or storage. This allows a corresponding milk product to essentially retain its original consistency even over an extended period.

[0003] Recently, the trend in the food industry has also been toward offering products with as few additives as possible. However, if milk is to be mixed with an acidic component such as coffee, the challenge is to counteract the effects of, for example, the acidity of the coffee and / or the high temperature of freshly brewed coffee in an alternative way and to prevent unwanted flocculation during production and / or storage. WO 2012 / 017043 relates to a beverage product comprising a partially denatured protein system including kappa-casein and beta-lactoglobulin, wherein the product has a pH between 5.6 and 6.3, preferably between 5.8 and 6.3. SUMMARY OF THE INVENTION

[0004] It is an object of the present invention to provide an alternative process by which a mixed beverage made from milk and an acidic component can be produced and stored with as little flocculation as possible.

[0005] The problem is solved by a method for producing a cold mixed drink from milk and an acidic component, which comprises the following steps in this order: A milk denaturation step. The milk is heated to a denaturation temperature T DENAT before being mixed with an acidic component. The denaturation temperature T DENAT lies in a range from 72 °C to 155 °C. The milk heated in this way is held at the denaturation temperature T DENAT for a denaturation time t DENAT , which lies in a range from 30 seconds to 1 hour.

[0006] The denatured milk is then mixed with an acidic component.

[0007] The mixture of milk and the acidic component is then heat-treated to increase shelf life. For this purpose, the mixture is heated to a temperature T HALT , which lies within a range of 63 °C to 155 °C, and the mixture is held at this temperature T HALT for a heat treatment time t HALT .

[0008] The heat-treated mixture is then homogenized at a homogenization pressure p HOM in a range from 75 bar to 275 bar, and after homogenization the mixture is cooled to a temperature in a range from 4°C to 25°C.

[0009] The milk and the acid component are mixed in such a ratio that the mixture, after homogenization and cooling, has a pH value in the range of 5.8 to 7.0.

[0010] The process allows milk to be mixed with an acidic component without significant flocculation being formed during the mixing or manufacturing process.

[0011] It has been found that, in particular, a denaturing step prior to mixing the milk—i.e., without the acidic component—can produce a corresponding cold milk drink that is stable against potential flocculation during production and storage. Thus, if the milk is subjected to a separate denaturing step as described here, the milk can be mixed with an acidic component without the risk of flocculation and, if desired for production-technical and / or energy-related reasons, even under elevated temperature conditions. The mixture can then be subjected to a common heat treatment as required for preservation and finally homogenized as a finished product before storage.It is currently assumed that the separate denaturation step of the milk reduces the proportion of native milk proteins and thus results in fewer flocculated components in the milk already present during mixing.

[0012] The process described here can make it possible to dispense with the use of acidity regulators. Such acidity regulators are used in conventional processes, especially when an acidic component must be added to milk. They serve to stabilize the pH value and thus ultimately counteract the coagulation of milk proteins caused by the acidic component.

[0013] The process described here can also make it possible for further additives such as stabilizers, emulsifiers and / or binding agents to be eliminated, since a stable milk-based mixed drink can be produced simply by the previously described sequence of temperature and pressure treatments of the various ingredients.

[0014] A mixture with a final pH value in the range of 5.8 to 7.0 has proven suitable for producing a final product that is stable with regard to flocculation simply by choosing the right process parameters. The term "final product" refers to the finished product as it is packaged and ultimately sold in stores. If the final pH value is too low, the risk of unwanted flocculation during production and / or storage increases.

[0015] The denaturation step of the milk can, for example, take place in a tank heated to the denaturation temperature T DENAT or in a heat exchanger, such as a plate or tube heat exchanger.

[0016] Heat treatment of the mixture of milk from the denaturation step and the acid component serves to increase shelf life, as is necessary for the sale of perishable, natural dairy products. It can be done directly, for example, via infusion or ultra-perishability, or indirectly, for example, via tubular or plate heat exchangers. Depending on the type of heat treatment, such as pasteurization, high-temperature pasteurization, or ultra-high temperature treatment, the appropriate equipment or system can be selected.

[0017] The homogenization of milk or milk mixtures can be performed in any suitable homogenizer, for example, a two-stage piston homogenizer. The pressures specified here correspond to the total pressure applied during homogenization.

[0018] It may be necessary for the mixture to be cooled to a homogenization temperature T HOM after heat treatment for homogenization.

[0019] Cooling can be achieved passively by transferring the homogenized mixture to a storage room at the desired temperature and leaving it there, allowing it to cool down to the storage room temperature over time. However, it is particularly advantageous to actively cool the heat-treated and homogenized mixture, for example, using a heat exchanger such as a plate or tube heat exchanger.

[0020] The temperature to which the heat-treated and homogenized mixture is finally cooled can, for example, correspond to the storage temperature at which the mixture is to be stored until filling. The storage temperature, in turn, depends, for example, on the type of mixture and the heat treatment carried out to increase the shelf life of the mixture. For example, an ultra-high-temperature treatment mixture can be stored at a higher temperature, such as room temperature, provided it is stored in a sterile environment. A pasteurized mixture, on the other hand, may require storage at lower temperatures, such as 4°C to 12°C. Here, too, storage should be carried out in a sterile environment, if necessary, to avoid recontamination.

[0021] For example, storage in a sterile tank is suitable. Using such a sterile tank is particularly suitable for preventing recontamination, as it is itself treated to be germ-free, i.e., sterile.

[0022] Mixing here refers to the mixing process of the milk from the denaturation step and the acidic component. The addition of, for example, flavoring substances and / or other ingredients is understood as adding rather than mixing. It may be intended that the milk and the acidic component are brought to the same temperature for mixing, for example. However, it has been shown that due to the separate denaturation treatment of the milk, the temperature at which mixing takes place has no or no significant and thus negligible influence on the stability of the produced milk-based beverage. The choice of temperatures for the milk and the acidic component can therefore also be coordinated with process and energy-related aspects in mind.

[0023] In the context of the present invention, milk is understood to mean a milk-based liquid component. In this sense, one can also refer to the milk component. Milk can, for example, be whole milk, skimmed milk, semi-skimmed milk, milk standardized in fat content, cream, or combinations thereof. Milk standardized in fat content is usually understood to mean a mixture of semi-skimmed milk or skimmed milk and cream. Skimmed milk, for example, typically has a fat content of approximately 0.05% and cream a fat content of 37%. By selecting an appropriate mixing ratio of the different types of starting milk, a desired fat content of the milk component can be set in a targeted and reproducible manner. Milk can, for example, also be one or more milk fractions or a milk processing product.A milk fraction is understood here to be a fraction of milk obtained by a separation process such as filtration and / or centrifugation. Examples include whey or buttermilk, or components of such a fraction such as milk proteins or milk fats. The milk fraction can be in powder or liquid form, for example. Milk can also be a combination of one or more of the above-mentioned milk varieties with one or more milk fractions.

[0024] For example, the milk may have already undergone a treatment to reduce the lactose content before mixing, or such a treatment may be performed on the mixture after the homogenization step and / or after the cooling step, provided recontamination cannot occur. For this purpose, lactase may be added to the milk, or lactase may be added to the mixture after the homogenization step and before storage.

[0025] The milk can be pre-stored before the denaturation step begins and brought into the process at the desired start of denaturation. If necessary, the milk from pre-stored storage can first be subjected to pre-homogenization, as described later. Suitable storage temperatures for pre-stored milk range from 4°C to 8°C.

[0026] Flavoring agents include, for example, sugar or sugar varieties such as caramelized sugar syrup, glucose syrup, maltodextrin, honey, agave syrup and preparations thereof, sweeteners, cocoa powder, chocolate powder, and other flavorings. Such flavorings can be flavors, natural flavors, flavoring substances, flavor extracts, artificial flavors, or combinations thereof. Additives such as acidity regulators, stabilizers, emulsifiers, and binding agents, which are used to influence the consistency or stability of the produced milk beverage, must be distinguished from flavoring agents.

[0027] The acidic component can be, for example, fruit juice, fruit juice concentrate, fruit pulp, fruit puree and fruit preparations thereof, vegetable juice, vegetable juice concentrate, cereals and other fermented natural ingredients and preparations thereof, coffee, and / or tea, tea infusion and (liquid) tea extract, for example from powder or paste, and preparations thereof.

[0028] The specifications given here regarding treatment temperatures, times, and pressures are particularly suitable for using coffee or coffee extract as the acidic component. If a different acidic component is to be used, the settings can be adjusted accordingly within the specified parameters.

[0029] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the denaturation time t DENAT is in a range from 30 seconds to 1 hour.

[0030] The denaturation time t DENAT is adapted to the selected denaturation temperature T DENAT. With regard to the denaturation temperature T DENAT and the denaturation time t DNAT, the higher the denaturation temperature T DENAT, the shorter the denaturation time t DENAT. By coordinating the denaturation temperature T DENAT and the denaturation time t DNAT, the degree of denaturation of the native whey proteins can be influenced and a relatively high degree of denaturation of these proteins can be achieved. It is currently assumed that the denaturation step achieves a relatively high denaturation of native whey proteins, ranging from 60 to 99%, or a denaturation ranging from 60% to 100% when this specifically relates to the whey protein β-lactoglobulin B.During subsequent steps of the manufacturing process, such as mixing with an acidic component or preservation, or even during storage, fewer native milk proteins would be present, which could precipitate. The minimum required or optimal degree of denaturation, which should be targeted for a stable milk-based mixed drink, can be influenced not only by the raw material properties but also by process-related aspects. If a specific degree of denaturation within the above-mentioned range is targeted, the determination of the denaturation time t DNAT to be used can thus also be made taking into account additional aspects such as process-related conditions or raw material properties (such as the acid content of the acidic component, acid content in the recipe, etc.).

[0031] Excessively long denaturation, which could trigger a so-called Maillard reaction, is undesirable, as this could lead to undesirable coloration and / or flavor changes in the milk or the subsequent milk mixture. A shorter denaturation time may be undesirable, especially from a process-technical perspective.

[0032] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, a degree of denaturation of the native whey protein β-lactoglobulin B is produced by means of the denaturation step of the milk, which is in a range of 60% to 100%.

[0033] Accordingly, it can be provided, as mentioned, to achieve a degree of denaturation of the native whey protein β-lactoglobulin B in this range by adjusting, for example, the denaturation time t DENAT and / or the denaturation temperature T DNAT , and if necessary taking into account further process conditions such as conditions when mixing the milk and the acidic component and / or when homogenizing, and / or raw material properties of the milk and / or the acidic component.

[0034] The whey protein β-lactoglobulin B has established itself among experts as a suitable standard for determining or assessing the degree of denaturation of a milk component, as it represents a fraction of the total whey proteins that is very sensitive to denaturation. The degree of denaturation of β-lactoglobulin B is described as the percentage of denatured β-lactoglobulin B relative to the total β-lactoglobulin B fraction.

[0035] In this context, denaturation of 100% of the β-lactoglobulin B fraction is said to occur when measured values ​​above 99% are achieved.

[0036] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory thereto, a degree of denaturation of the native whey protein β-lactoglobulin B is produced by means of the denaturation step of the milk, which degree is in a range of 80% to 100%, in particular in a range of 80% to 99% or in a range of 80% to 95%.

[0037] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, a degree of denaturation of the native whey protein β-lactoglobulin B is produced by means of the denaturation step of the milk, which is in a range of 90% to 100%.

[0038] It may be that a denaturation time t DENAT ranging from 240 sec to 420 sec, or more specifically from 240 sec to 320 sec, is particularly suitable. For example, a denaturation time t DENAT of 420 sec is suitable for a denaturation temperature T DENAT of 86°C, while a denaturation time t DENAT of 320 sec is suitable for a denaturation temperature T DENAT of 88°C, or a denaturation time t DENAT of 240 sec is suitable for a denaturation temperature T DENAT of 95°C. For example, if a denaturation temperature T DENAT of 72°C is used, the suitable denaturation time t DENAT is 1 h (hour).

[0039] For example, if a denaturation temperature T DENAT of 155 °C is used, the suitable denaturation time t DENAT is approximately 30 seconds.

[0040] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory thereto, the denaturation time t DENAT , which lies in a range of 60 seconds to 420 seconds, is preferably in a range of 100 seconds to 320 seconds.

[0041] In particular, a denaturation time t DENAT in the range of 100 sec to 200 sec may be suitable.

[0042] As an example, a denaturation time t DENAT of 120 seconds is mentioned. This denaturation time t DENAT may be suitable if the other process conditions (process engineering or raw material engineering as mentioned above) can be adjusted to achieve a degree of denaturation in one of the ranges described above.

[0043] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the denaturation time t DENAT is in a range from 240 seconds to 320 seconds, with a denaturation temperature T DENAT in a range from 86 °C to 95 °C.

[0044] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory thereto, the denaturation step of the milk is carried out at a denaturation temperature T DENAT in a range from 86 °C to 95 °C.

[0045] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned or yet to be mentioned, unless contradictory, the denaturation temperature T DENAT is 90 °C and the denaturation time t DENAT is 300 sec.

[0046] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned or yet to be mentioned, unless contradictory, the denaturation temperature T DENAT is 90 °C and the denaturation time t DENAT is 120 sec.

[0047] It has been shown that even with a comparatively shorter denaturation time t DENAT a sufficiently high degree of denaturation is achieved, which makes it possible to produce a mixture which is sufficiently stable against flocculation, for example during mixing or storage.

[0048] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory thereto, the homogenization of the heat-treated mixture takes place at a temperature T HOM which is in a range from 65 °C to 80 °C.

[0049] It can be provided that in one embodiment of the process, which can be combined with any embodiment mentioned and yet to be mentioned, the homogenization of the mixture is carried out at a pressure p HOM which is in a range of 75 bar to 250 bar, preferably in a range of 100 bar to 170 bar, very particularly preferably in a range of 100 bar to 150 bar.

[0050] In one embodiment of the process according to the invention, which can be combined with any of the aforementioned and yet-to-be-mentioned embodiments, unless contradictory, the heat treatment of the mixture is pasteurization. For this purpose, the temperature T HALT is in a range from 63°C to 133°C, and the heat treatment time t HALT is in a range from 2 seconds to 200 seconds. By means of pasteurization, the mixture is treated in a gentle manner to kill vegetative pathogenic germs. The corresponding pasteurized end product can be stored stably in a refrigerated state for approximately 30 to 60 days. During pasteurization, the temperature T HALT and the heat treatment time t HALT are coordinated. For example, a batch pasteurization can be carried out at 63°C for approximately 2000 seconds. In a high-temperature pasteurization, i.e., pasteurization in the higher temperature range, a temperature of 125°C can be applied for approximately 2 to 8 seconds.

[0051] In one embodiment of the process according to the invention, which can be combined with any embodiment mentioned or yet to be mentioned, unless contradictory, the heat treatment of the mixture is ultra-high heating. For this purpose, the temperature T HALT is in a range from 130 °C to 155 °C and the heat treatment time t HALT is in a range from 2 seconds to 8 seconds. Ultra-high heating not only kills vegetative germs but also any spores that may be present. The corresponding ultra-high-heated end product can be stored unrefrigerated for 90 days or more. Even with ultra-high heating, the temperature T HALT and the treatment time t HALT are typically coordinated. For example, ultra-high heating can be carried out at 130 °C for 10 seconds to 30 seconds. If a higher temperature is to be selected, a temperature of 155 °C for 1 second to 10 seconds is possible, for example.

[0052] Alternatively, the heat treatment can also be sterilization, provided that the properties of the mixture are not affected.

[0053] In an embodiment of the method according to the invention, which can be combined with any of the aforementioned and yet-to-be-mentioned embodiments, provided that they do not contradict each other, the milk is prehomogenized immediately before the denaturation step. The prehomogenization pressure p PRE is in a range from 100 bar to 300 bar. In particular, the prehomogenization pressure p PRE can be in a range from 150 to 250 bar.

[0054] Such pre-homogenization of the milk can also improve stability and reduce flocculation. It is believed that by further reducing the diameter of the fat globules in the milk, the protein structures in the milk are further modified, which in turn contributes to reducing flocculation.

[0055] In an embodiment of the method according to the invention, which can be combined with any of the aforementioned and yet-to-be-mentioned embodiments, provided they do not contradict each other, prehomogenization takes place at a temperature T PRE ranging from 65 °C to 80 °C. The prehomogenization temperature T PRE can, for example, be adapted to the properties of the milk and / or selected according to plant-related aspects. For example, a higher temperature T PRE is selected if milk with a higher fat content is used.

[0056] In an embodiment of the process according to the invention, which can be combined with any of the aforementioned and yet-to-be-mentioned embodiments, unless contradictory, the milk and / or the acidic component comprise flavoring agents. The extent to which such flavoring agents are added to the milk or the acidic component, or both, can be decided based on process-related aspects. In order not to counteract the effect of increasing shelf life, it may be provided to add such optional flavoring agents before heat treatment of the mixture and / or the individual components.

[0057] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the milk and the acid component are mixed in a mixing ratio which, after homogenization and cooling, results in a mixture having a pH value in a range of 5.8 to 6.8.

[0058] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory thereto, the milk and the acidic component are mixed in a mixing ratio which, after homogenization and cooling, results in a mixture which has a pH value which is in a range of 6.2 to 6.8 and / or which has an acidity which is in a range of 4.5 °SH to 12.5 °SH.

[0059] A mixture with a final pH value in this range has proven particularly suitable for producing a flocculation-stable end product simply by selecting the process parameters discussed here. The term "end product" refers to the finished product as it is packaged and ultimately sold in stores. If the final pH value is too low, the risk of unwanted flocculation during production and / or storage increases.

[0060] The °SH refers to the acidity according to Soxhlet-Henkel.

[0061] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the milk and the acid component are mixed in a mixing ratio which, after homogenization and cooling, results in a mixture having a pH value in a range of 6.3 to 6.6.

[0062] Depending on the components used in the mixture (particularly the acidic component and milk), the critical lower limit of the pH of the mixture can vary slightly. Factors such as the nature / type of the acidic component used, its acidity and / or desired volume fraction in the final product, and / or the protein content of the milk used can influence the pH and stability of the mixture. Fruits, for example, can contain more acid than coffee, so fruit-based mixtures can tend to be more acidic than coffee-based mixtures. In addition, the protein content of the milk can have a buffering and thus pH-stabilizing effect. For example, a pH of approximately 6.2 was measured for a mixture of skimmed milk, cream, sugar, and fruit puree, whereby the mixture met the stability requirements.A lower pH value of the mixture may also be possible, although it has been shown that mixtures with a pH below 5.8 do not exhibit the desired stability against flocculation. For example, the recipe in Table 1 has a pH value between 6.5 and 6.6, measured in the final product.

[0063] On the other hand, the pH can be increased, for example, by adding a pH stabilizer, for example, to 6.9 or even 7.0 in a mixture of milk and coffee. A pH of 7.0 is considered a suitable upper limit for the pH of the mixture of milk and acidic component or the final product, with a pH of 6.9 being particularly suitable, and especially a pH of 6.8 or even 6.6.

[0064] For a mixture according to the invention of milk and the acidic component, depending on the properties of the mixture, a final pH value can result which can be derived from the combination of one of the lower limits discussed above with one of the upper limits discussed above.

[0065] When speaking of the pH value of the mixture after homogenization and cooling, the pH value is inherently related to the end product (i.e. the final pH value).

[0066] It may be particularly advantageous for the mixture, after homogenization and cooling, to have a pH value in a range from 6.3 to 6.6 and / or an acidity in a range from 5.5 °SH to 11.9 °SH, for example in the case of a milk-coffee-based mixture.

[0067] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the mixture is first stored after cooling at a storage temperature and then filled, or the mixture is filled directly after cooling.

[0068] In an embodiment of the process according to the invention, which can be combined with any of the aforementioned and yet-to-be-mentioned embodiments, unless conflicting, the storage temperature is in a range of 4°C to 25°C. Filling of the mixture can take place at the storage temperature. Typically, filling takes place in the appropriately designated container in which the finished mixture is to be sold. As already mentioned, the storage temperature and / or the filling temperature can be adapted to the type of heat treatment used (pasteurization, ultra-high temperature treatment, sterilization).

[0069] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the acidic component is selected from a group comprising: fruit juice, fruit juice concentrate, fruit pulp, fruit puree and fruit preparations thereof, vegetable juice, vegetable juice concentrate, cereals and other fermented natural ingredients and preparations thereof, coffee, and / or tea, tea infusion and liquid tea extract, for example from powder or paste, and preparations thereof.

[0070] The acidic component has an acidic pH, i.e., a pH below 7.0. What is crucial for the properties of the mixture of milk and the acidic component is not so much the pH of the acidic component itself, but rather its proportion in the milk mixture and the resulting pH of the mixture with the applied mixing ratio.

[0071] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the acidic component is coffee.

[0072] Coffee here refers to a liquid component containing coffee. Coffee can be, for example, brewed coffee beans or the product of a so-called cold brew process. The liquid component containing coffee can also be dissolved instant coffee, coffee concentrate diluted from paste, or preparations thereof.

[0073] In one embodiment of the method according to the invention, which can be combined with any of the aforementioned and yet-to-be-mentioned embodiments, provided they do not conflict, the coffee is produced from coffee beans. For this purpose, the coffee beans are first roasted. Depending on the device used and / or the coffee bean, roasting can take place at a temperature between 150°C and 240°C, for example, for a period of 10 to 20 minutes. A suitable roaster is, for example, a Probat roaster.

[0074] The roasted coffee beans are then ground and subjected to a brewing process. The brewing process can be carried out at a higher temperature range, for example, within a range of 80°C to 100°C, particularly within a range of 86°C to 96°C. However, the brewing process can also be carried out at a lower temperature range, for example, if the coffee is to be produced using the cold brew method. In this case, the brewing process can be carried out at a temperature range of 2°C to 25°C. With this method, brewing typically takes place over a longer period of time, for example, several hours or days.

[0075] Suitable coffee beans include Arabica varieties from Central America, South America, India, or other origins, or blends thereof. Robusta varieties from various origins can also be suitable.

[0076] The liquid coffee produced by brewing can then be temporarily stored for up to four days, for example. A suitable storage temperature is between 4 °C and 8 °C. During intermediate storage, the coffee can be heated from storage temperature to a mixing temperature T MIX and then added to the milk stream after denaturation. Such pre-storage has the advantage that the coffee can be produced relatively independently of the milk and can be fed directly from the storage into the process for the production of the cold coffee-milk blend.

[0077] It is also possible for the freshly brewed coffee to be transferred directly from the brewing process into the milk stream for mixing. In this case, the coffee may need to be cooled or heated to adjust to the mixing temperature, or the coffee may be taken directly from the coffee stream at the desired mixing temperature (T MIX) and then requires no additional temperature treatment.

[0078] In an embodiment of the method according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the coffee is stored separately before mixing with the milk and preheated to a mixing temperature T MIX for mixing.

[0079] In an embodiment of the process according to the invention, which can be combined with any embodiment mentioned and yet to be mentioned, unless contradictory, the mixing temperature T MIX corresponds essentially to the denaturation temperature T DENAT of the milk + / - 15 °C.

[0080] As previously mentioned, due to the separate denaturation treatment of the milk, the temperature at which it is mixed has no, or at least no significant, and thus negligible, influence on the stability of the resulting milk-based beverage. The choice of milk and coffee temperatures can therefore also be adjusted based on process and energy-related considerations.

[0081] For example, for making a cold coffee-milk mixture, the fat content of the milk used can range from 0.05% to 10%. The milk used can be tailored to the final product. For example, if a cappuccino is to be made, milk with a fat content of approximately 1.5% is particularly suitable, whereas for making a macchiato, milk with a fat content of approximately 5.0% is particularly suitable.

[0082] Also described are various mixed drinks made from milk and an acidic component, produced by the process according to the invention. Such a mixed drink can be stored stably for at least 50 days without precipitating.

[0083] This stable shelf life refers to product-appropriate storage. For example, pasteurized mixed drinks can be stored for at least 50 days at 4 to 10 °C, while ultra-high-temperature mixed drinks can be stored for up to three or more months, even at room temperature, for 50 days. It is currently assumed that the prior denaturation of the milk significantly reduced the proportion of milk proteins that can be coagulated after production. In this context, stable shelf life is understood to mean storage for the aforementioned periods without visible coagulation. The presence of coagulation is assessed visually on the final product.

[0084] An example milkshake can consist of: Milk, and the acidic component, and flavoring substances, and / or one or more additives selected from a group comprising: stabilizers, emulsifiers and binders.

[0085] The use of an acidity regulator was not necessary here.

[0086] Another example milk drink can consist of Milk, and the acidic component, and flavoring substances.

[0087] This milk drink does not contain any additives for stabilization.

[0088] An example milk-based drink might consist of milk and the acidic component. No additives, including flavorings, are used. This could, for example, be a product made from milk and coffee (café au lait) or a milk-fruit juice blend.

[0089] In an example milkshake, the acidic component may be coffee.

[0090] In an example milkshake, the acidic component may be fruit puree.

[0091] The milk of an example milk mix drink can be: whole milk, skimmed milk, semi-skimmed milk, milk or cream with a fat content standardized to standardize on, or one or more milk fractions, or a combination thereof. The milk or its composition can depend in particular on which exact end product is to be produced. For a cold cappuccino with coffee as the acidic component, for example, a composition can be selected that has a fat content of approximately 1.5%, whereas for a macchiato, also with coffee as the acidic component, a composition can be selected that has a fat content of 5%. In addition to or alternatively to the fat content of the milk, the viscosity or consistency can also be adjusted in general via the composition of the milk.

[0092] In an exemplary milk-based beverage, the milk can be whole milk, skimmed milk, semi-skimmed milk, fat-standardized milk or cream, or a combination thereof. Furthermore, the milk comprises at least one milk fraction, which preferably comprises milk protein.

[0093] In particular, the consistency of the final milk mixture can be influenced in a natural way by adding milk protein.

[0094] It is currently assumed that the separate pretreatment of milk without coffee extract or acidic components leads to a change in the protein structures in the milk, thus achieving stabilization during further heat treatments to increase shelf life and subsequent homogenization, which occur through the addition of the acidic component, such as the coffee component, in a slightly acidic range. Thus, based on the process alone, the addition of acidity regulators, stabilizers, emulsifiers, and / or binding agents can be dispensed with, if desired, without compromising the stability of the milk mixture with regard to possible flocculation.

[0095] Also described is an installation 1 which is suitable for carrying out a process with the process steps and in the sequence as described above. Depending on the process, the installation 1 may have additional

[0096] Elements. Annex 1 includes at least the following devices and components: a denaturing device 2 for carrying out a separate denaturing treatment of the milk. With this denaturing device 2, the milk is heated to the denaturing temperature T DENAT and held at the denaturing temperature T DENAT for the denaturing time t DENAT. Such a denaturing device 2 can, for example, be a heat exchanger, such as a plate or tube heat exchanger. a device 9 for combining the denatured milk and the acidic component to form a mixture. Since in this case streams are combined, the mixing step takes place by combining them. a device 3 for carrying out a heat treatment of the mixture to increase its shelf life. With this device 3, the mixture, which comprises milk from the denaturing treatment and the acidic component, is treated to increase its shelf life.Such a device 3 is designed to heat the mixture to the required temperature T HALT for the corresponding time t HALT , and accordingly, for example, to carry out pasteurization or ultra-high temperature treatment. The device can be, for example, a tubular or plate heat exchanger, or, if the heat treatment is carried out via infusion or hyperization, a device using the infusion or hyperization process. A first homogenization device 4 for homogenizing the heat-treated mixture. The first homogenization device 4 is designed to build up the desired homogenization pressure p HOM . Such a homogenization device 4 can, for example, be a two-stage piston homogenizer.It may be possible for the homogenization device 4 to be functionally connected to a heat exchanger to bring the mixture to be homogenized to a desired homogenization temperature T HOM , as described later. A cooling device 5 for cooling the heat-treated and homogenized mixture to a storage temperature. The storage temperature can, as already described above, be in a range from 4°C to 25°C. The cooling device 5 can, for example, be a heat exchanger such as a plate or tube heat exchanger.Lines 6 for receiving the milk and conducting a milk stream, lines 7 for receiving the acidic component and conducting a stream containing the acidic component, lines 8 for receiving the mixture comprising the milk and the acidic component and for conducting the mixture stream, and a controller 10 for controlling the process according to one of the above-described embodiments or combinations thereof as a continuous process.

[0097] In this context, a continuous process is understood to be a process in which the individual components and the mixture are processed in a continuous sequence of process steps, i.e., essentially without interruption. The respective streams of liquid components (be it milk, the acid component, or the mixture) are continuously flowing from one device to the next. Therefore, there is no so-called "batch production" here, in which the individual components or the mixture are processed in batches and ultimately combined as a single product. Accordingly, the milk, the acid component, and the mixture are moved in continuously flowing streams from one device in Plant 1 to the next.

[0098] The individual components and the mixture are therefore moved in corresponding lines 6, 7, 8. For controlled transport of the liquids through lines 6, 7, 8 and the various devices, system 1 may comprise one or more operatively connected pressure pumps and / or valves with which a respective flow rate is controlled. Such pumps and / or valves may, for example, be operatively connected to one or more lines 6, 7, 8 for controlling the individual volume flows.

[0099] The controller 10 is designed to carry out the process in an embodiment described above or a combination of embodiments as a continuous process on the system 1. For example, the controller can control the various devices and / or one or more lines 6, 7, 8 such that they are adapted to the volumes of the liquid flows to be moved. These can be, for example, adjustments to the capacities of the devices and / or adjustments to regulate the respective liquid volumes and their flow properties. For example, the controller 10 can be used to control a process in which the liquid flow of the milk accounts for 75 to 95% of the total liquid volume, and the liquid flow of the acidic component accounts for 5 to 25% of the total liquid volume. The adjustments can be made individually for the desired end product.

[0100] The controller 10 is preferably also designed to control the corresponding process parameters such as treatment times of the milk, the acidic component and / or the mixture such as t DENAT , t HALT , and / or treatment temperatures T DENAT , T HALT , T HOM , T PRE , T MIX , ​​and / or treatment pressures such as p HOM and p PRE , which are used for example during denaturation and / or during heat treatment to increase the shelf life and / or for one or more homogenization steps, and / or to adapt these if necessary depending on the line conditions such as the length of the line and diameter as well as to the desired flow rate.

[0101] The device 9 for merging the milk flow and the flow containing the acidic component is, for example, a simple T-connector. The merging can be controlled by one or more valves in the milk flow line 6 and / or the line 7 for the acidic component, in this case the coffee flow line. However, the device 9 for merging the milk flow and the flow containing the acidic component can also have other line configurations other than a T-piece, as long as it allows the two previously separately formed lines to be merged into a common mixture line. A dosing valve can additionally control the merging.

[0102] The system 1 can comprise additional cooling devices 5', 5", etc., in order to reduce the temperature of one or both individual components or of the mixture as needed in possible intermediate steps. For example, it may be necessary to cool the mixture of milk and the acidic component to a desired, lower homogenization temperature T HOM after the heat treatment in order to increase its shelf life by means of a cooling device 5'. It is also possible, for example, to cool one of the individual components for an intermediate storage step, for example to a storage temperature. If, for example, coffee is used as the acidic component, the coffee brewed from coffee beans can be cooled to, for example, 4°C for intermediate storage by means of a cooling device 5". Such cooling devices 5, 5', 5" can each be a heat exchanger, such as a plate or tube heat exchanger.

[0103] The system may additionally comprise one or more heating devices 12 to preheat the corresponding liquids for a desired process step, if necessary. Such a heating device may, for example, be a heat exchanger.

[0104] An exemplary system may include a second homogenization device 11. This second homogenization device is used to pre-homogenize the milk, as described above. The second homogenization device 11 may, for example, be a two-stage piston homogenizer designed to apply the desired pre-homogenization pressure p PRE to the milk. The second homogenization device 11 may be functionally connected to a heating device 12 to heat the milk to a desired pre-homogenization temperature T PRE for pre-homogenization.

[0105] The denaturing device 2 can be a heat exchanger, preferably a plate heat exchanger or a tubular heat exchanger. If designed as a heat exchanger, the denaturing device 2 includes a heat-holding section designed to keep the milk hot for the required time. This can be achieved, for example, by selecting the length, the diameter, or the material of the corresponding line.

[0106] The device 9 for combining the denatured milk stream and the stream containing the acidic component into a mixture may be a tube-based connector, for example, a T-connector, which preferably includes a metering valve. Alternatively, the tube-based connector may have a shape other than a T-shape, for example, a Y-shape, as long as the shape allows the mixing or combining of the denatured milk stream with the stream containing the acidic component, as mentioned above.

[0107] The device 3 for carrying out the heat treatment can be a heat exchanger, preferably a plate heat exchanger or a tubular heat exchanger, or a device using the infusion or supersaturation method. If the device 3 for carrying out the heat treatment is a heat exchanger, it includes a heat-holding section designed to keep the milk hot for the required time. This can be achieved, for example, by selecting the length, the diameter, or the material of the corresponding line.

[0108] The homogenization device 4 can be a piston homogenizer.

[0109] The cooling device 5 may be a heat exchanger, preferably a plate heat exchanger or a tube heat exchanger.

[0110] In an exemplary system, the lines 6, 7, 8 connect the various devices in such a way that the devices are fluidically connected in a sequence such that the method is carried out continuously according to the inventive sequence described above: For example, at least one line 6 for receiving the milk and guiding a milk stream is fluidly connected to the denaturing device 2 in order to guide the milk into the denaturing device 2. Furthermore, one or more further lines 6 for receiving and guiding the milk may be provided, for example, for feeding the milk into a heating device 12 before the milk is fed into the denaturing device 2. In this case, the milk can also be guided through a line 6 from the heating device 12 into the denaturing device.Analogously, by means of one or more lines 6, the milk flow can be guided from the denaturing device 2 to the device 9 for combining the denatured milk and the acidic component to form a mixture; or to and / or from one or more devices which are arranged upstream of the denaturing device 2, for example a second homogenizing device 11 for pre-homogenization and / or an additional heating device 12, as described, for example, in connection with pre-homogenization.

[0111] Also by way of example, at least one line 7 for receiving the acidic component and conducting a flow containing the acidic component is fluidly connected to the device 9 for combining the denatured milk and the acidic component into a mixture in order to conduct the acidic component into this device 9. It can be provided that one or more lines 7 ensure the flow of the acidic component to and / or from devices arranged upstream of the mixing device, for example, if the acidic component is to be heated in an additional heating device 12 before being mixed with the milk.

[0112] Also by way of example, at least one line 8 for receiving the mixture and conducting the mixture flow fluidly connects the device 9 for combining the milk and the acidic component with the device 3 for heat-treating the mixture. Additional lines 8 can be provided to conduct the mixture flow, for example, from the heat-treatment device 3 to and / or from a cooling device 5, 5' and / or the first homogenization device 4 and / or the intermediate storage.

[0113] For example, see Annex 1, as it is shown in Figure 3 described.

[0114] When specifying ranges, the mentioned key values ​​are included in the range. SHORT DESCRIPTION OF THE CHARACTERS

[0115] Embodiments of the present invention are explained in more detail with reference to figures. Figure 1the essential steps of the process in a schematic block diagram; Figure 2 in a further schematic block diagram, a special embodiment of the method for producing a cold coffee-milk mixture with additional, optional steps, and Figure 3 in a schematic block diagram, a plant in which the various plant elements are arranged to carry out a continuous process. DETAILED DESCRIPTION OF THE FIGURES

[0116] Figure 1shows the essential steps of the process in a schematic block diagram. Milk alone, i.e., without the addition of the acid component, undergoes a denaturation step. Immediately afterward, the acid component is added. Due to the temperature treatment, this mixing step is less susceptible to flocculation. The resulting mixture is then subjected to heat treatment, which is necessary to increase its shelf life. The heat-treated mixture can then be homogenized and finally cooled. The resulting mixture is stable against flocculation.

[0117] A highly schematic temperature profile is shown above the block diagram. In this case, the heat treatment of the mixture to increase shelf life takes place at a higher temperature (T HALT ) than the denaturation of the milk (T DENAT ), while homogenization takes place at a slightly lower temperature (T HOM ) than the denaturation. The temperature then drops sharply, which in this case corresponds to cooling to a lower temperature, for example, for storage.

[0118] Figure 2 shows a schematic block diagram of an exemplary embodiment of the method for producing a cold coffee-milk mixture with additional, optional steps. For clarity, an exemplary temperature profile for the respective steps is also shown here.

[0119] This process is based on the following recipe according to Table 1: Table 1 INGREDIENT AMOUNT IN RECIPE Whole milk 75g / 100g Brewed coffee 17g / 100g cream 5g / 100g Sugar 3g / 100g

[0120] The desired milk is prepared and stored until the desired start of the production process. For this purpose, the milk can, for example, have a temperature in the range of 4°C to 8°C. In this case, the milk is stored in a 4°C storage room.

[0121] Coffee is prepared by brewing coffee from coffee beans. To do this, the beans are first roasted at a relatively high temperature, for example, in a range of 150°C to 240°C. The roasted coffee beans are then ground and brewed at a slightly lower temperature. The brewing temperature can, for example, be in a range of 85°C to 97°C. In this example, the coffee is brewed at 88°C to 92°C. The coffee produced in this way is then initially stored in an intermediate storage facility at a temperature in the range of 4°C to 10°C, in this case in a 4°C storage room, until it can be added to the milk stream. The temperature curve of the coffee drops accordingly.

[0122] Flavoring agents can be added to either the milk or the coffee, or both. This is indicated by the dashed arrows. In this example process, sugar is added to the milk component and subjected to the denaturation step together with it.

[0123] In this process, the stored milk undergoes an initial "pre-homogenization" and is preheated to the appropriate temperature T PRE . The pre-homogenization temperature T PRE can be in the range of 65°C to 75°C, for example, at a pressure between 150 and 200 bar. The milk is then further heated to the denaturation temperature T DENAT , and the milk is denatured, for example, for 120 seconds or up to 300 seconds at approximately 90°C.

[0124] At the same time, the temporarily stored coffee is also heated to a mixing temperature T MIX and then added to the milk after denaturation. The mixing temperature T MIX in this case is also approximately 90 °C.

[0125] The resulting mixture of milk and coffee is then further heated to a pasteurization temperature T HALT , which in this case can range from 120 °C to 133 °C. Specifically, 72 °C was used for pasteurization for 15 seconds. During this heat treatment, vegetative germs are killed, thus rendering the milk mixture low in germs.

[0126] Immediately following pasteurization, the mixture is homogenized again. In this case, homogenization takes place at a temperature T HOM in the range of 65 °C to 70 °C, so that the mixture is cooled for homogenization. Cooling can be achieved, for example, using a tube or plate heat exchanger.

[0127] The mixture is homogenized, for example, at a pressure in the range of 100 to 150 bar. The homogenized mixture is then cooled to a storage temperature of 5 °C to 10 °C and stored in a sterile tank. Once desired, the cooled mixture can then be filled at storage temperature. Filling is typically done in containers in which the final mixture product will later be sold.

[0128] Figure 3shows a schematic block diagram of a plant 1 in which the various plant elements for carrying out a continuous process are arranged. This plant 1 is particularly suitable for a process such as Figure 2 in which coffee is used as the acidic component, the steps described below being controlled by means of the controller 10 with the settings described above.

[0129] In a first liquid stream, the milk is first taken from a pre-storage area, for example a storage tank at 4 °C, and is fed via one or more lines 6 for the milk flow to the second homogenization device 11. Flavoring substances can be added to the milk, for example, directly after removal from the pre-storage area, as in connection with Figure 2described. The second homogenization device 11 is designed to perform the previously described pre-homogenization of the milk. In the system described here as an example, the milk, after storage, is first passed through a heating device 12, in this case a heat exchanger, with which the milk is preheated to the pre-homogenization temperature T PRE . Immediately thereafter, the milk is then passed into the second homogenization device 11 for pre-homogenization.

[0130] The now pre-homogenized milk is then heated further via lines 6 by means of a heating device 12 to the desired denaturation temperature T DENAT and then immediately passed to the denaturation device 2, where it is subjected to the denaturation treatment as described above. Figure 2In the recipe mentioned, the volume of the milk stream is 75 percent by volume (vol%) of the total volume. The total volume is the volume of the finished product made up of milk and the acidic component, in this case, coffee. The lines 6 are designed for the controlled transport of the milk stream with such a volume. The control system 10 ensures, for example, that the desired denaturation time t DENAT is not significantly exceeded or undershot, given the line characteristics and flow rates. This also applies to the other treatment times.

[0131] At the same time, liquid, brewed coffee is taken from the pre-storage and preheated to the desired mixing temperature T MIX by means of a heating device 12. For the Figure 2In the recipe mentioned above, the volume of the coffee stream is 25 percent by volume (vol%) of the total volume. For this purpose, the coffee is first transported to the heating device 12 and then further via appropriately designed coffee flow lines 7.

[0132] Immediately after the denaturing treatment of the milk, the coffee stream from coffee stream line 7 is combined with the preheated coffee and the milk stream from milk stream line 6 by means of a device 9 for combining the milk stream and the acid component stream. The subsequent devices and lines 8 are controlled to the corresponding final volume (100 percent by volume).

[0133] The final mixture is then conveyed via lines 8 to a device 3 for heat-treating the mixture to increase its shelf life, where it undergoes the appropriate heat treatment. In this case, this device is a pasteurization device, more precisely a tubular heat exchanger. In this case, the temperature T HALT of the shelf-life treatment is higher than the denaturation temperature T DENAT of the milk and the mixing temperature T MIX of the coffee. Therefore, the mixture for the heat-treatment to increase its shelf life is preheated to the temperature T HALT via the tubular heat exchanger and held for the appropriate time for pasteurization.

[0134] The pasteurized mixture of milk and coffee is then fed via lines 8 to the first homogenization device 4. In this case, this is a two-stage piston homogenizer, with which the Figure 2described pressure p HOM and at temperature T HOM is applied to the mixture.

[0135] Since this homogenization takes place at a lower temperature T HOM than the pasteurization, the mixture, before it reaches the first homogenization device 4, is cooled from the pasteurization temperature T HALT to the homogenization temperature T HOM by means of a cooling device 5', here a heat exchanger, and then passed on to the homogenization device 4.

[0136] Finally, the pasteurized and homogenized milk-coffee mixture is fed from the homogenization device 4 to the cooling device 5, in this case a heat exchanger, via appropriate mixture flow lines 8, where it is cooled to the desired storage temperature. Since the mixture was pasteurized in this process, a storage temperature of 4 °C is selected. Storage can then take place, for example, in one or more sterile tanks. It can also be provided that filling into the appropriate containers takes place immediately after cooling.

[0137] Each of the steps described herein and the devices used are under substantially complete control by the controller 10. List of reference symbols

[0138] 1System 2Denaturing device 3Device for performing a heat treatment of a mixture to increase its shelf life, 4First homogenization device 5.5'Cooling device 6Milk flow lines 7Lines for acid component flow 8Mixture flow lines 9Device for combining the milk and acid component flow 10Control system 11Second homogenization device 12Heating device

Claims

1. Method for producing a cold mixed beverage of milk and an acidic component, wherein the method comprises the following steps in this order: • a denaturing step of the milk, wherein the milk is heated to a denaturing temperature TDENAT which is in a range of 72°C to 155°C prior to mixing with the acidic component and the milk is maintained at the denaturing temperature TDENAT for a denaturing period tDENAT, which is in a range of 30 sec to 1 h. • subsequently mixing the denatured milk with the acidic component to a mixture, • heat treating the mixture to increase shelf life, wherein the mixture is heated to a temperature THALT which is in a range of 63 °Cto 155 °C, and maintaining the mixture at the temperature THALT for a heat treatment period tHALT, • homogenizing the heat-treated mixture at a homogenizing pressure pHOM which is in a range of 75 bar to 275 bar, and • cooling the mixture to a temperature that is in a range of 4°C to 25°C, wherein the milk and the acidic component are mixed in such a mixing ratio that the mixture, after homogenization and cooling, has a pH value which is in a range of 5,8 to 7,0.

2. Method according to claim 1, characterized in that a degree of denaturation of a native whey protein β-lactoglobulin B, which is in a range from 60% to 100%, is produced by means of the denaturing step of the milk.

3. Method according to claim 1, characterized in that the denaturing period tDENAT is in a range of 60 sec to 420 sec, preferably in a range of 100 sec to 320 sec.

4. Method according to claim 3, characterized in that the denaturing step of the milk is carried out at a denaturing temperature TDENAT in a range of 86°C to 95°C.

5. Method according to one of the preceding claims, characterized in that the homogenization of the heat-treated mixture is carried out at a temperature THOM which is in a range of 65°C to 80°C.

6. Method according to one of claims 1 to 5, characterized in that the heat treatment of the mixture is a pasteurization, wherein the temperature THALT is in a range of 63°C to 133°C and the heat treatment period tHALT is in a range of 2 sec to 2000 sec.

7. Method according to one of claims 1 to 5, characterized in that the heat treatment of the mixture is an ultra-high temperature heating, wherein the temperature THALT is in a range of 130°C to 155°C and the heat treatment period tHALT is in a range of 1 sec to 30 sec.

8. Method according to one of the preceding claims, characterized in that the milk is prehomogenized immediately prior to the denaturing step, wherein the prehomogenization pressure pPRE is in a range of 100 bar to 300 bar, preferably in a range of 150 to 250 bar.

9. Method according to claim 8, characterized in that the prehomogenization is carried out at a temperature TPRE which is in a range of 65°C to 80°C.

10. Method according to one of the preceding claims, wherein the milk and / or the acidic component comprises flavoring agents.

11. Method according to one of the preceding claims, characterized in that the milk and the acidic component are mixed in such a mixing ratio that the mixture, after the homogenization and the cooling, has a pH value that is in a range of 6,2 to 6,8, preferably in a range of 6,3 to 6,6, and / or in that the mixture, after the homogenization and the cooling, has a degree of acidity which is in a range of 4,5°SH to 12,5 °SH, preferably in a range of 5,5 °SH to 11,9 °SH.

12. Method according to one of the preceding claims, characterized in that the mixture is first stored after the cooling at a storage temperature and then filled, or in that the mixture is filled directly after the cooling.

13. Method according to claim 12, characterized in that the storage temperature is in a range of 4°C to 25°C, and / or in that the filling is performed at the storage temperature.

14. Method according to one of the preceding claims, characterized in that the acidic component is selected from a group comprising: fruit juice, fruit juice concentrate, fruit pulp, fruit puree and fruit preparations thereof, vegetable juice, vegetable juice concentrate, cereals and other fermented natural ingredients and preparations thereof, coffee and liquid coffee extract and preparations thereof, and / or tea, tea infusion and liquid tea extract, and preparations thereof.

15. Method according to one of the preceding claims, characterized in that the acidic component is coffee or a liquid coffee extract.

16. Method according to claim 15, characterized in that the coffee is stored separately before the mixing with the milk and is preheated to a mixing temperature TMIX for mixing.

17. Method according to claim 16, characterized in that the mixing temperature TMIX essentially corresponds to the denaturing temperature TDENAT of the milk + / -15°C.