METHOD FOR PRODUCING A COLD MIXED MILK DRINK

Abstract

A method for producing a cold mixed beverage made of milk and an acidic component having a denaturing step of the milk is disclosed. The milk is heated to a denaturing temperature T.sub.DENAT that is in a range of 72° C. to 155° C. prior to mixing with the acidic component and is maintained at the denaturing temperature T.sub.DENAT for a denaturing period t.sub.DENAT and then the denatured milk is mixed with the acidic component. The mixture is heat treated to increase the shelf life. The mixture is heated to a temperature T.sub.HALT which is in a range of 63° C. to 155° C., and maintained at the temperature T.sub.HALT for a heat treatment period t.sub.HALT. The heat-treated mixture is homogenized at a homogenizing pressure P.sub.hom which is in a range of 75 bar to 275 bar, and then cooled to a temperature that is in the range of 4° C. to 25° C.

Claims

1. Method for producing a cold mixed beverage made 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 T.sub.DENAT which is in a range of 72° C. to 155° C. prior to mixing with the acidic component, and is maintained at the denaturing temperature T.sub.DENAT for a denaturing period t.sub.DENAT, then mixing the denatured milk with the acidic component to form a mixture, heat treating the mixture to increase shelf life, wherein the mixture is heated to a temperature T.sub.HALT which is in a range of 63° C. to 155° C., and maintaining the mixture at the temperature T.sub.HALT for a heat treatment period t.sub.HALT, homogenizing the heat-treated mixture at a homogenizing pressure P.sub.hom which is in a range of 75 bar to 275 bar, and cooling the mixture to a temperature that is in the 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 and 7.0.

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

3. Method according to claim 1, characterized in that the denaturing period t.sub.DENAT is in a range from 30 sec to 1 h.

4. Method according to claim 3, characterized in that the denaturing period t.sub.DENAT is in a range from 60 sec to 420 sec, preferably in a range from 100 sec to 320 sec.

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

6. Method according to claim 1, characterized in that the homogenization of the heat-treated mixture is carried out at a temperature T.sub.hom which is in a range from 65° C. to 80° C.

7. Method according to claim 1, characterized in that the heat treatment of the mixture is a pasteurization, wherein the temperature T.sub.HALT is in a range of 63° C. to 133° C. and the heat treatment period t.sub.HALT is in a range of 2 sec to 2000 sec.

8. Method according to claim 1, characterized in that the heat treatment of the mixture is a ultra-high temperature heating, wherein the temperature T.sub.HALT is in a range of 130° C. to 155° C. and the heat treatment period t.sub.HALT is in a range of 1 sec to 30 sec.

9. Method according to claim 1, characterized in that the milk is prehomogenized immediately prior to the denaturing step, wherein the prehomogenization pressure p.sub.pre is in a range from 100 bar to 300 bar, preferably in a range from 150 to 250 bar.

10. Method according to claim 9, characterized in that the prehomogenization is carried out at a temperature T.sub.pre which is in a range from 65° C. to 80° C.

11. Method according to claim 1, wherein the milk and/or the acidic component comprises flavoring agents.

12. Method according to claim 1, characterized in that the milk and the acidic component are mixed in such a mixing ratio that the mixture, after homogenization and cooling, has a pH value that is in a range from 6.2 to 6.8, preferably in a range of 6.3 to 6.6, and/or in that the mixture, after homogenization and 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.

13. Method according to claim 1, characterized in that the mixture is first stored after cooling at a storage temperature and then filled, or in that the mixture is filled directly after cooling.

14. Method according to claim 13, 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.

15. Method according to claim 1, 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.

16. Method according to claim 1, characterized in that the acidic component is coffee or a liquid coffee extract.

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

18. Method according to claim 17, characterized in that the mixing temperature T.sub.MIX essentially corresponds to the denaturing temperature T.sub.DENAT of the milk +/−15° C.

19. Mixed beverage of milk and an acidic component, prepared according to claim 1, characterized in that the mixed beverage can be stored stably for at least 50 days without flocculation.

20. Mixed milk beverage according to claim 19, which consists of milk, and the acidic component, and flavoring substances, and one or more additives selected from a group comprising: stabilizers, emulsifiers and binders.

21. Mixed milk beverage according to claim 19, which consists of milk, and the acidic component, and flavoring substances.

22. Mixed milk beverage according to claim 19, characterized in that it consists of milk and the acidic component.

23. Mixed milk beverage according to claim 19, characterized in that the acidic component is coffee.

24. Mixed milk beverage according to claim 19, characterized in that the acidic component is fruit puree.

25. Mixed milk beverage according to claim 19, characterized in that the milk is: whole milk or skimmed milk or semi-skimmed milk or milk standardized for fat content or cream or one or more milk fractions or a combination thereof.

26. Mixed milk beverage according to claim 19, characterized in that the milk is: whole milk or skimmed milk or semi-skimmed milk or milk standardized for fat content or cream or a combination thereof, and in that the milk comprises at least one milk fraction which preferably comprises milk protein.

27. Plant (1) for carrying out a method having the method steps and in the sequence according to claim 1 for producing a cold mixed milk beverage made of milk and an acidic component, wherein the plant (1) comprises at least the following devices and plant parts: a denaturing device (2) for carrying out a separate denaturing treatment of the milk, a device (9) for mixing the denatured milk and the acidic component to form a mixture, a device (3) for performing a heat treatment on the mixture to increase its shelf life, a homogenizing device (4) for homogenizing the heat-treated mixture, a cooling device (5) for cooling the heat-treated and homogenized mixture to a storage temperature, characterized in that the plant is adapted to perform the method continuously, wherein the milk, the acidic component and the mixture are moved in continuously flowing streams from one device of the plant (1) to the next, and wherein the plant (1) further comprises: lines (6) for receiving the milk and guiding a milk flow, lines (7) for receiving the acidic component and guiding a flow with the acidic component, lines (8) for receiving a mixture comprising the milk and the acidic component and for guiding a mixture flow, and a controller (10) for controlling the method according to one of claims 1 to 16 as a continuous method.

28. Plant (1) according to claim 27, characterized in that the denaturing device (2) is a heat exchanger, preferably a plate heat exchanger or a tube heat exchanger.

29. Plant (1) according to claim 27, characterized in that the device (9) for merging the denatured milk flow and the flow with the acidic component into a mixture is a tube-based connector, for example a T-connector, preferably comprising a metering valve.

30. Plant (1) according to claim 27, characterized in that the device (3) for carrying out the heat treatment is a heat exchanger, preferably a plate heat exchanger or a tube heat exchanger, or an apparatus according to the infusion or uperization method.

31. Plant (1) according to claim 27, characterized in that the homogenizing device (4) is a piston homogenizer.

32. Plant (1) according to claim 27, characterized in that the cooling device (5) is a heat exchanger, preferably a plate heat exchanger or a tube heat exchanger.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0137] Exemplary embodiments of the present invention are explained in more detail with reference to figures, wherein:

[0138] FIG. 1 shows the main steps of the method in a schematic block diagram;

[0139] FIG. 2 shows in a further, schematized block diagram a special embodiment of the method for the production of a cold coffee-milk mixture with additional, optional steps, and

[0140] FIG. 3 shows a schematic block diagram of a plant in which the various plant elements for carrying out a continuous method are arranged.

DETAILED DESCRIPTION OF THE FIGURES

[0141] FIG. 1 shows a schematic block diagram of the main steps of the method. Milk alone, i.e. without the addition of the acidic component, is subjected to a denaturing step. Immediately afterwards, the acidic component is added. Due to the temperature treatment, this mixing step is less susceptible to flocculation. The resulting mixture is then subjected to a heat treatment, which is necessary to increase shelf life. The heat-treated mixture can then be homogenized and finally cooled. The resulting mixture is stable to flocculation.

[0142] Above the block diagram a highly schematized temperature curve is shown. In this case, the heat treatment of the mixture to increase shelf life takes place at a higher temperature T.sub.HALT than denaturation of the milk T.sub.DENAT, while homogenization takes place at a slightly lower temperature T.sub.HOM than the denaturation. Subsequently, the temperature drops sharply, which in this case corresponds to cooling to a lower temperature for storage, for example.

[0143] FIG. 2 shows a in schematic block diagram an exemplary embodiment of the method for producing a cold coffee-milk mixture with additional, optional steps. For the sake of clarity, an exemplary temperature curve for the respective steps is also shown here.

[0144] This method is based on the of formulation according to Table 1:

TABLE-US-00001 TABLE 1 SHARE IN INGREDIENT FORMULATION Whole milk 75 g/100 g Brewed coffee 17 g/100 g Cream  5 g/100 g Sugar  3 g/100 g

[0145] The desired milk is provided and stored until the desired start of the manufacturing process. For this purpose, the milk can have a temperature in a range of 4° C. to 8° C., for example. In this case, the milk is stored in a 4° C. storage room.

[0146] Coffee is provided by obtaining a brewed coffee from coffee beans. For this purpose 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 then brewed at a slightly lower temperature. For example, the brewing temperature may be in the 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 first stored cooled in an intermediate storage 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 fed to the milk flow. The temperature curve of the coffee drops accordingly.

[0147] Flavoring substances can be added to either the milk or the coffee, or both. This is indicated by the dashed arrows. In this exemplary method, sugar is added to the milk component and subjected to the denaturing step together with it.

[0148] In this illustrated method, the upstream milk is subjected to a first “prehomogenization” and preheated to the corresponding temperature T.sub.PRE for this purpose. In this case, the temperature of the prehomogenization T.sub.PRE can be in the range of 65° C. and 75° C., for exam pie at a pressure between 150 and 200 bar. The milk is then heated further, to the denaturing temperature T.sub.DENAT, and denaturation of the milk takes place, for example, for 120 sec or up to 300 sec at approximately 90° C.

[0149] At the same time, the temporarily stored coffee is also heated to a mixing temperature and then added to the milk after denaturation. In this case, the mixing temperature T.sub.MIX is also around 90° C.

[0150] The resulting mixture of milk and coffee is then heated further to a pasteurization temperature T.sub.HALT, which in this case can be in the range of 120° C. to 133° C. Specifically, a temperature of 72° C. was applied here for 15 sec for pasteurization. During this heat treatment, vegetative germs are killed and the milk mixture is thus rendered low of germs.

[0151] Immediately after pasteurization, the mixture is then homogenized again. In this case, homogenization takes place at a temperature T.sub.HOM in a range of 65° C. to 70° C., so that the mixture is cooled for homogenization. Cooling can be carried out, for example, with a tubular or plate heat exchanger.

[0152] Homogenization of the mixture takes place, for example, at a pressure in a range of 100 to 150 bar. Subsequently, the homogenized mixture is cooled to a storage temperature which is in a range of 5° C. to 10° C. and stored in a sterile tank. Once this is desired, the cooled mixture can then be filled at the storage temperature. Filling is usually carried out into such containers in which the final mixture product is to be sold later.

[0153] FIG. 3 shows in a schematized block diagram a plant 1 in which the various plant elements for carrying out a continuous method are arranged. This plant 1 is particularly suitable for a method as described for FIG. 2, in which coffee is used as the acidic component, wherein the steps described below are controlled with the settings described above by means of the controller 10.

[0154] In a first liquid flow, the milk is first taken from a preliminary storage, for example a storage tank at 4° C., and fed to the second homogenizing device 11 via one or more lines 6 for the milk flow. Flavoring substances can be added to the milk, for example, directly after removal from the preliminary storage, as described in connection with FIG. 2. The second homogenizing device 11 is designed to carry out the previously described prehomogenization of the milk. In the plant described here by way of example, after storage the milk is first passed over a heating device 12, in this case a heat exchanger, with which the milk is preheated to the prehomogenization temperature T.sub.PRE. Immediately thereafter, the milk is then fed into the second homogenizing device 11 for prehomogenization.

[0155] Subsequently, the now prehomogenized milk is first further heated to the desired denaturing temperature T.sub.DENAT via lines 6 by means of a heating device 12 and immediately thereafter passed to the denaturing device 2, where it is subjected to the denaturation treatment as described above. For the formulation referred to in FIG. 2, the volume of the milk flow is 75% by volume (Vol %) of the total volume. The total volume here is the volume of the final mixed product of milk and the acidic component, as in this case coffee. The lines 6 are suitably designed for the controlled transport of the milk flow with such a volume. By means of the controller 10, it is ensured, for example, that the desired denaturing period t.sub.DENAT is not significantly exceeded or undercut for the given line characteristics and flow rates. This also applies to the other treatment times.

[0156] At the same time, liquid, brewed coffee is taken from the pre-storage and preheated to the desired mixing temperature T.sub.MIX by means of a heating device 12. For the formulation mentioned for FIG. 2, 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 onward via appropriately designed coffee flow hues 7.

[0157] Immediately after the denaturation treatment of the milk, the coffee stream from coffee flow line 7 is combined with the preheated coffee and the milk flow from milk flow line 6 by means of a device 9 for merging the milk flow and the acidic component stream. The subsequent devices and lines 8 are adapted to the corresponding final volume (100 percent by volume) under the control of a controller.

[0158] The final mixture at hand is then fed via lines to a device 3 for carrying out heat treatment of a mixture to increase its shelf life, where it is subjected to the appropriate heat treatment. In this case, it is a pasteurization device, more precisely a tubular heat exchanger. In this case, the temperature T.sub.DENAT of the treatment to increase shelf life is higher than the denaturing temperature T.sub.DENAT of the milk and the mixing temperature T.sub.MIX of the coffee. Therefore, the mixture for the heat treatment to increase shelf life is preheated to the temperature T.sub.HALT via the tubular heat exchanger and held for pasteurization for the appropriate time.

[0159] The pasteurized mixture of milk and coffee is now fed to the first homogenizing device 4 via lines 8. In this case, this is a two-stage piston homogenizer, with which the pressure P.sub.HOM described in FIG. 2 and at the temperature T.sub.HOM are applied to the mixture.

[0160] Since this homogenization takes glace at a lower temperature than pasteurization, before the mixture enters the first homogenizing device 4, it is cooled from the pasteurization temperature T.sub.HALT to the homogenization temperature by means of a cooling device 5′, in this case a heat exchanger, and then passed on to the homogenizing device 4.

[0161] Finally, the pasteurized and homogenized milk-coffee mixture is fed from the homogenizing device 4 to the cooling device 5, in this case a heat exchanger, by means of appropriate mixture flow lines 8, where it is cooled to the desired storage temperature. Since in this method the mixture has been pasteurized, a storage temperature of 4° C. is selected. Storage can now take place in one or more sterile tanks, for example, it can also be provided that filling into the corresponding containers takes place immediately after cooling.

[0162] Each of the steps described herein and the devices used are under substantially complete control of the controller 10.

LIST OF REFERENCE NUMERALS

[0163] 1 Plant

[0164] 2 Denaturing device

[0165] 3 Device for performing a heat treatment of a mixture to increase its shelf life,

[0166] 4 First homogenizing device

[0167] 5,5′ Cooling device

[0168] 6 Milk flow lines

[0169] 7 Lines for acidic component flow

[0170] 8 Mixture flow lines

[0171] 9 Device for merging the milk flow and the acidic component flow

[0172] 10 Controller

[0173] 11 Second homogenizing device

[0174] 12 Heating device