Method and system for providing high solids whole milk concentrate or powder

Abstract

The present invention relates to a method for producing a whole milk powder and a system for producing a high solids whole milk concentrate with reduced energy consumption.

Description

[0001] Title of Invention

[0002] Method and system for providing high solids whole milk concentrate or powder

[0003] Technical Field

[0004] The present invention relates to a method for producing a whole milk concentrate and powder and a system for producing a high solids whole milk concentrate and powder with reduced energy consumption.

[0005] Background

[0006] Whole milk powder, also known as full cream milk powder, is a widely consumed dairy product that has a diverse range of applications in the food industry. It is manufactured by carefully removing the water content of milk, which produces a stable, easy-to-store powder. Modern manufacturing of whole milk powder involves a series of steps, such as spray dryers, to ensure the production of high-quality and long- lasting powdered whole milk.

[0007] The primary input material for the production of whole milk powder is fresh milk obtained from dairy farms. Modern facilities today separate the milk into cream and low fat milk by a series of steps involving clarification, centrifugation, and collection of separated components, and then standardization. The cream typically has a fat content in the range of 30-40 w%, while the low fat milk has a fat content which is usually below 0.5 w% fat, but the fat content may be higher. The fat content in the milk that is used in the production of whole milk powder is adjusted for producing a consistent product, usually by combining the low fat milk and the cream in a process known as standardization. The milk is usually also pasteurized and then homogenized to ensure a uniform distribution of fat globules, preventing cream separation. The subsequent step involves the concentration of milk through evaporation, which results in the removal of a significant portion of water content, leading to the formation of a milk concentrate. The final step in the manufacturing process of whole milk powder is the conversion of the milk concentrate into powder form using spray drying technology, the milk concentrate typically has a solids content of 45 - 53 w% before being fed to the spray drier. This process involves the atomization of the concentrated milk solution into fine droplets, which are subsequently exposed to hot air within a drying chamber. As the droplets come into contact with the hot air, the water evaporates rapidly, leaving behind dried milk particles that are collected and processed into powdered form.

[0008] Spray dryers are especially important in the production of whole milk powder, as they enable efficient water removal while maintaining the nutritional integrity and desired properties of the milk. However, the operation of spray dryers is energy- intensive, as it requires the generation of hot air at high temperatures to facilitate the rapid evaporation of water from the milk droplets. The energy consumption of spray dryers varies depending on several factors, including the scale of production, the design of the drying system, and the specific process parameters employed. Efforts have been made to enhance the energy efficiency of spray drying systems through the implementation of advanced heat recovery mechanisms and improved process control strategies.

[0009] Maintaining the quality of the resulting powder is a concern in the production of milk powders, in particular whole milk powder having a high fat content. The literature is scarce, but attempts have been made to reduce surface fat formation for milk powders in order to improve the quality and the reconstitution of the powders into a beverage, as it is a known problem that high fat content can cause problems in / the end product, cf. Foerster et al. Food Hydrocolloids 70 (2017), 163 - 180. In this study the problem was solved by adding carrageenan. The problem has also been addressed in US 6,780,452 which describes the challenges with maintaining the good properties of, in particular, highly concentrated milk products and as a solution describes a method in which the main principle is described as the ability to spray dry a milk concentrate containing up 63% by weight solids concentration this is achieved by drying a standardized milk in two steps with an intermediate homogenization step followed by spray drying. This solution is described to provide a satisfactory quality and productivity can be increased however the aspect of obtaining such advantages is not related to energy saving. Despite these efforts, there remains a need for processes which can further reduce the energy consumption of the spray drying step of whole milk powder production while maintaining productivity, the quality and standard high solids content of the obtained powder.

[0010] Summary of the invention

[0011] An object of the present invention is to address the above-mentioned drawbacks, and in particular to provide a method by which a lower overall energy consumption can be achieved for the production of whole milk powder and at the same time obtain comparable high solids content and quality of the whole milk powder.

[0012] In a first aspect, this and further objects are achieved by a method for producing a whole milk concentrate and powder, the method comprising the steps of: separately providing a low fat milk and a cream concentrating the low fat milk thereby obtaining a concentrated low fat milk concentrating the cream thereby obtaining a concentrated cream and a fat reduced fraction mixing the concentrated cream and the concentrated low fat milkto obtain a whole milk concentrate.

[0013] By this method, the cream and the low fat milk are separately concentrated, such that a whole milk concentrate with a high total solids content can be obtained. This high solids content in turn leads to less water to be removed in the step of drying the whole milk concentrate to a whole milk powder. It was surprising that the problems with high solids and fat content, related to free fat and size of the fat globules that the prior art has sought to solve can be overcome with the method of the invention without compromising the quality of the final powder. Hence, the method both overcomes a quality problem without using special measures as presented in the prior art, and at the same time at a lower energy consumption.

[0014] Preferably the concentrate is further subjected to the step of: drying the whole milk concentrate whereby the whole milk powder is obtained.

[0015] It is contemplated that the concentrate is dried either directly downstream or it may be transported to another site for subsequent drying to a powder. If transported it may be necessary to pasteurize or otherwise treat the concentrate to prevent microbial growth.

[0016] The total solids content of the whole milk concentrate before drying may in the method of the invention be as high as in the range of 50-65 w%. Producing higher total solids content in this range requires more energy in the concentrating step, however, the extra energy required by the additional concentrating is offset by the energy savings of the subsequent drying step. This is because concentrating uses approximately 10 times less energy than removing the same amount of water in a drying step, leading to an overall energy saving of up to. 20 %. Hence, the energy saving is twofold: Spray drying of a concentrate instead of a more diluted stream and using centrifugation over evaporation. Another effect of the invention is that the result of concentrating the skim milk and cream fractions separately allows for, in an energy efficient manner, to arrive at solid contents that, when combined, result in the same or higher total solid content than prior art methods. This is while maintaining the high quality of the final product in terms of nutritional and functional quality aspects of the product also with the higher solids content in the feed, thus said feed having a different composition.

[0017] The separately provided low fat milk and cream may be obtained from the same portion of milk or can be obtained from two separate portions of milk.

[0018] A cream is in the context of this disclosure a fatty component of milk obtained from a separation of a milk. A cream typically contains at least 28 w% milk fat.

[0019] A low fat milk is in the context of this disclosure a low fat component of milk obtained from a separation of a milk, which low fat milk typically has a fat content of up to 2 w%, such as 0.03-1.2 w%, preferably 0.05-1 w%, more preferably 0.06-0.15 w%. As such in an embodiment the fat content of the low fat milk is up to 2 w%.

[0020] In an embodiment of the method of the present disclosure, the low fat milk is concentrated by falling film evaporation, reverse osmosis followed by falling film evaporation, reverse osmosis followed by falling film evaporation and / or agitated film evaporation, in the step of concentrating the low fat milk. Preferably, the low fat milk is concentrated by reverse osmosis followed by falling film evaporation. In an embodiment a homogenization step is included, preferably between the mixing and drying steps.

[0021] In an embodiment of the method of the present disclosure, the low fat milk is concentrated to obtain a low fat milk concentrate with a total solids content in the range of 50-64 w% of the concentrated low fat milk, in the step of concentrating the low fat milk.

[0022] In a further embodiment, the low fat milk is concentrated by a method selected from i) Falling film evaporation to achieve a solids content of the low fat milk in the range of 50-55 w%, preferably 52-55 w%, ii) Reverse osmosis followed by falling film to achieve a solids content of the low fat milk in the range of 50-55 w%, preferably 52-55 w% iii) Falling film evaporation followed by agitation evaporation to achieve a solids content of the low fat milk of up to 64 w%, preferably 55-60 w% and iv) Reverse osmosis followed by falling film again followed by agitation evaporation to achieve a solids content of the low fat milk of up to 64 w%, preferably 55- 60 w%.

[0023] In a particular embodiment the low fat milk is concentrated by reverse osmosis followed by falling film evaporation to obtain a low fat milk concentrate with a total solids content in the range of 52-55 w% of the concentrated low fat milk, in the step of concentrating the low fat milk. At present a preferred embodiment is reverse osmosis followed by falling film evaporation as this combination has shown to provide a good balance of solids content in the final product versus installation and operational costs.

[0024] In an embodiment of the method of the present disclosure, the cream is concentrated by centrifugation in the step of concentrating the cream.

[0025] In an embodiment of the method of the present disclosure, the cream has a fat content in the range of 38-42 w%. The majority of total solids in the cream is fat, typically 90 w% of the total solids in the cream is fat.

[0026] In an embodiment of the method of the present disclosure, the cream is concentrated to a total solids content in the range of 55-80 w%, such as 65-80 w%, more preferred 75-78 w% of the concentrated cream, in the step of concentrating the cream. The lower end of the solids content may be relevant with higher cost of energy. Presently the preferred range is 75-78 w%, such as 78 w%.

[0027] In a presently preferred embodiment, the solid content in the concentrated low fat milk is 52 w% and the solid content in the concentrated cream is 78 w%. In an embodiment of the method of the present disclosure, the ratio of solids content of the concentrated cream to concentrated low fat milk is in the range of 1:5 to 1:2.5, preferably 1:4.1 to 1:2.9.

[0028] In embodiments where the solid content in the concentrated low fat milk is 52 w% and the solid content in the concentrated cream is 78 w%, the ratio is in the range of 1:3.5 to 1:4.5, preferably 1:3.65 to 1:4.05.

[0029] These ratios result in a whole milk concentrate that has a solid content of 50 to 65 w%, preferably 52 to 60 w%, such as 55 to 58 w%, more preferred 56-58 w%. It is contemplated that other specific ratios may be applied provided they result in a whole milk concentrate having a solid content within the range specified and a fat content in the powder of 26 to 42 w% cf., the standard below, and preferably around 26-28 w%.

[0030] This ratio ensures that the final product, when the fractions are provided according to the invention, will result in the desired total solids in an energy efficient manner while obtaining the level of fat and protein and sugar as required to qualify as a whole milk powder according to known standards such as Codex Alimentarius 207. As is known to the skilled person total solids refers to and is constituted mainly of fat, carbohydrates, and protein. The primary source of fat is the cream fraction whereas the primary source of sugar and protein is the low fat milk fraction. It is also contemplated according to the standard that carbohydrate either milk permeate, or edible-grade lactose may be added.

[0031] In an embodiment of the method of the present disclosure, the whole milk concentrate is dried to obtain a whole milk powder with a total solids content of at least 90 w%, preferably at least 95 w%, more preferred at least 97 w% of the powder, in the step of drying the whole milk concentrate. The higher the solid content, the longer the shelf life.

[0032] In an embodiment, the method further comprises a homogenization step in between the mixing and drying step. The homogenization in the step of homogenizing the whole milk concentrate may be a 1-step homogenization. More preferably, the homogenization in the step of homogenizing the whole milk concentrate is a 2-step homogenization. In a 1-step homogenization process, the milk is forced through a single homogenization valve, where high pressure is applied to break down the fat globules. This process effectively reduces the size of the fat globules but may not achieve complete homogenization, leading to a relatively larger particle size distribution. A 2- step homogenization process involves passing the milk through two homogenization valves in succession, each operating at different pressures. This method allows for further reduction of the fat globule size and a more uniform distribution of fat particles throughout the milk.

[0033] In an embodiment of the method of the present disclosure, the whole milk concentrate is dried by spray drying or roller-drying, in the step of drying the homogenized whole milk concentrate. Preferably, drying is carried out via spray drying.

[0034] In an embodiment of the method of the present disclosure, the method further comprises the steps of: providing a low fat milk powder, which low fat milk powder is obtained from drying a milk optionally with a fat content in the range of 0-2 w% fat, prior to the step of drying the homogenized whole milk concentrate, supplying the low fat milk powder to the homogenized whole milk concentrate.

[0035] Low fat milk powder may be added as needed to obtain the desired relative composition of solid components.

[0036] In yet an embodiment of the method, the fat reduced fraction is combined with the low-fat milk before concentration. In this embodiment the fat reduced fraction from the step of concentrating the cream is further utilized in the process thereby reducing waste.

[0037] Typically, the fat reduced fraction can contain up to 8 - 9% w / w of fat. According to a second aspect of the present disclosure, a system for producing a high solids whole milk concentrate or powder is provided, the system comprising a concentration unit, a centrifuge, a mixer, an optional homogenizer, and an optional spray dryer, wherein the concentration unit has an inlet for receiving skim milk and an outlet for discharging a concentrated low fat milk; the centrifuge has an inlet configured for receiving a cream and a first outlet for discharging a concentrated cream; and a second outlet for discharging a fat reduced fraction; optionally the second outlet for discharging the fat reduced fraction is fluidly connected to the inlet of the concentration unit, the mixer is fluidly connected to the outlets of the concentration unit and the centrifuge respectively and has an outlet for discharging a whole milk concentrate; the optional homogenizer has an inlet for receiving the whole milk concentrate and an outlet for discharging a homogenized whole milk concentrate, and the optional spray dryer has an inlet fluidly connected to the outlet of the mixer or the optional homogenizer.

[0038] The second aspect achieves at least the same objects and has at least the same advantages as the first aspect.

[0039] In an embodiment of the system of the present disclosure, the concentration unit comprises a reverse osmosis unit fluidly connected to a falling film evaporator; a reverse osmosis unit fluidly connected to a falling film evaporator which in turn is fluidly connected to an agitated film evaporator; or a falling film evaporator fluidly connected to an agitated film evaporator.

[0040] In an embodiment of the system, the spray dryer is mandatory. In another embodiment, the second outlet for discharging the fat reduced fraction is fluidly connected to the inlet of the concentration unit.

[0041] In an embodiment of the system of the present disclosure, the system furthermore comprises a heat pump configured to provide heat to the spray dryer.

[0042] Brief description of drawings

[0043] FIG. 1 shows an embodiment of a system for producing a whole milk powder according to the present disclosure. FIG. 2 shows a variation of figure 1 in which a homogenizer is included.

[0044] FIG. 3 shows an embodiment in which the fat reduced fraction is recycled and mixed with the low fat milk before concentration.

[0045] Detailed description

[0046] The present invention will now be described in more detail hereinafter with reference to the accompanying drawing, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness.

[0047] Referring to FIG. 1, an embodiment of system 100 for producing a whole milk powder is shown. The system 100 embodied comprises a concentration unit 101 comprising a reverse osmosis unit 101a and falling film evaporator 101b, a centrifuge 102, a mixer 103, a spray dryer 105, and a heat pump (not shown). It is contemplated that the concentration unit may comprise other variations as described herein. The reverse osmosis concentrator has an inlet 101a_i for receiving a low fat milk, such as skim milk, and an outlet 101a_o for discharging a concentrated skim milk (not shown). Similarly, the falling film evaporator 101b has an inlet 101b_i which is fluidly connected to the outlet of the reverse osmosis concentrator, for receiving the low fat milk leaving the reverse osmosis unit, and an outlet 101b_o for discharging a concentrated skim milk. The centrifuge 102 has an inlet 102a configured for receiving a cream and a first outlet 102b for discharging a concentrated cream. The mixer 103 is fluidly connected to the outlet 101b_o of the falling film evaporator 101b via the inlet 103x and to the outlet 102b of centrifuge 102 via the inlet 103y. The Mixer 103 has an outlet 103z for discharging a whole milk concentrate, which outlet is fluidly connected to an inlet 105a of the spray dryer 105. Heat is provided to the spray dryer 105 via a heat pump (not shown) to the spray dryer via inlet 106a.

[0048] Referring now to FIG. 2, the units and references are the same as shown in figure 1 unless specified. The centrifuge 103 has an outlet 103z for discharging a whole milk concentrate, the outlet is fluidly connected to the inlet 104a of the homogenizer 104. The outlet 104b of the homogenizer 104 is fluidly connected to an inlet 105a of a spray dryer 105

[0049] Further parts typically present in such systems are well-known to the skilled person, including for instance further inlets to and outlets from the falling film evaporator, the centrifuge, the mixer, the homogenizer, and the spray dryer, but also lines to and from the falling film evaporator, the centrifuge, the mixer, the homogenizer, and the spray dryer.

[0050] In a typical application, a low fat milk with a fat content of 0.06-0.15 w% is fed to the inlet of the concentration unit 101, such that a concentrated skim milk with a total solids content in the range of 52-55 w% of the concentrated skim milk is produced and discharged at the outlet 101b_o.

[0051] A cream with a fat content of 38-42 w% is fed to the inlet 102a of the centrifuge 102, and is centrifuged such that a concentrated cream with total solids content in the range of 75-78 w% of the concentrated cream is produced and discharged at the outlet 102b. The concentrated low fat milk and the concentrated cream are then fed to the mixer 103 via the inlets 103x and 103y, respectively. The concentrated cream and the concentrated low fat milk are mixed in a ratio of 1:1.4 by weight (1:4 based on the solids content of the concentrates) to produce a whole milk concentrate, which is then discharged via the outlet 103z into inlet 105a of the spray dryer 105. The whole milk concentrate is then spray dried by means of the spray dryer 105 to obtain a whole milk powder (not shown) with a total solids content of least 97 w% of the powder.

[0052] The whole milk concentrate may be discharged via the outlet 103z to the inlet 104a of the homogenizer 104 before entering the drier. In some embodiments the whole milk concentrate is then homogenized, preferably two-step homogenized, to produce a homogenized whole milk concentrate (not shown), which homogenized whole milk concentrate is then discharged via outlet 104b.

[0053] Now referring to FIG. 3 an embodiment is shown where the centrifuge 102 has an inlet 102a configured for receiving a cream and a first outlet 102b for discharging a concentrated cream and a second outlet 102c for discharging the fat reduced fraction. The second outlet 102c for discharging the fat reduced fraction is connected to the inlet of the concentration unit 101a_i.

[0054] In this embodiment, the cream with a fat content of 38-42 w% is fed to the inlet 102a of the centrifuge 102 and is centrifuged such that a concentrated cream with total solids content in the range of 75-78 w% of the concentrated cream is produced and discharged at the first outlet 102b and the fat reduced fraction is discharged from the second outlet 102c. The fat reduced fraction is then fed to the inlet of the concentration unit 101a_i and is combined with the low fat milk, either before or during feeding to the concentration unit. The concentrated cream and low fat milk fractions are then fed to the mixer 103 via the inlets 103x and 103y, respectively. The variation described in figure 3 is not limited to embodiments with homogenisation. Hence, it is contemplated that the same recirculation step may also be applied in the embodiment shown in figure 1.

[0055] The principles of the energy saving of the invention will be illustrated in the below examples.

[0056] Examples - energy saving

[0057] In the examples below the energy consumption for spray drying of whole milk has been calculated to compare the invention with traditional spray drying of whole milk.

[0058] Assumptions made for the calculation:

[0059] In the evaporator 418 kJ / kg of water is assumed removed and in the spray dryer 5256 kJ / kg of water is assumed removed. Assumptions in accordance with the numbers disclosed in Tanguy et al. "Concentration of dairy products using a thin film spinning cone evaporator" Journal of Food engineering, Vol. 166, Dec. 2015, pp 356- 363 were used. Direct enthalpy change for evaporation is assumed to be ~2400 kJ / kg of water evaporated. So as a rough estimate, a spray dryer has an efficiency of 50%. The mass flow that forms basis for the calculation is: The input is 30,000 kg / h of raw milk containing 13% w / w solids. Solid flow is 3,900 kg / h and water flow is 26,100 kg / h. The target humidity of the powder is assumed to be 4% w / w humidity, which means that 156 k / h water will remain in powder and a total of 25,944 kg / h of water is to be evaporated. It is the basis of this water removal the calculations are based.

[0060] In traditional production of whole milk powder comprising an evaporation and spray drying step, the evaporation step removes water to a solid content of 52% w / w. This means that the solid 3,900 kg / h leaving the evaporator comprises 3,391 kg / h of water. The water evaporated in the evaporator then equals 26,100 kg / h - 3,391 kg / h = 22,709 kg / h. The energy costs for evaporating this amount of water in the evaporator is 9.49E6 kJ / h. In the spray dryer, providing a final water content of 156 kg / h, 3,391 - 156 kg / h = 3,235 kg / h water needs to be removed. This means that the energy costs for removing water in the spray dryer is 17 E6 kJ / h. Hence, the total energy needed is: 9.49E6 kJ / h + 17 E6 kJ / h = 26.49 E6 kJ / h. cost according to the invention

[0061] In the step of concentrating the cream, a total of 1,175.6 kg / h of water is removed from the cream. In embodiments where the fat reduced fraction from the cream concentration step is added to the low fat milk before evaporation, the low fat milk contains 25,496 kg / h of water. Similarly, without recirculation of the fat reduced fraction, the low fat milk would contain 24,321 kg / h of water. Of the 25,296 kg / h of total water in the feed, 23,148 kg / h of water is to be evaporated in the concentration step, which in this example is assumed to be an evaporator. The energy cost in the evaporator would be 9.7E6 kJ / h. The concentrated low fat milk comprises 2,681 kg / h water. To reach the 4% w / w target humidity, the drying step must ensure 2,525 kg / h of water is evaporated. The energy cost for this step is 13.3E6 kJ / h. The total energy needed according to the invention is 9.7E6 kJ / h + 13.3E6 kJ / h = 23 E6 kJ / h.

[0062] If there is no additional cooling / heating for the method according to the invention the method would require consumption of 22.7E6 kJ / h compared to 26.49E6 kJ / h for traditional spray drying corresponding to an energy saving of approximately 14% compared to a prior art method. If assuming some additional heating in the method according to the invention an energy saving of around 11% would be expected.

Claims

Claims1. A method for producing a whole milk concentrate the method comprising the steps of: separately providing a low fat milk and a cream concentrating the low fat milk thereby obtaining a concentrated low fat milk concentrating the cream thereby obtaining a concentrated cream and a fat reduced fraction mixing the concentrated cream and the concentrated low fat milk to obtain a whole milk concentrate.

2. A method according to claim 1 wherein the concentrate is subjected to the step of drying the whole milk concentrate whereby a whole milk powder is obtained.

3. The method of claims 1 or 2, wherein in the step of concentrating the low fat milk, the low fat milk is concentrated by falling film evaporation, reverse osmosis followed by falling film evaporation and / or agitated film evaporation or falling film evaporation followed by agitated film evaporation.

4. The method according to any one of claims 1 to 3 further comprising the step of homogenizing the whole milk concentrate before the drying step and after the mixing step to obtain a homogenized whole milk concentrate.

5. The method according to any one of claims 1 to 4, wherein in the step of concentrating the low fat milk, the low fat milk is concentrated to obtain a low fat milk concentrate with a total solids content in the range of 50-64 w% of the concentrated low fat milk.

6. The method according to any one of the preceding claims, wherein in the step of concentrating the cream, the cream is concentrated by centrifugation.

7. The method according to any one of the previous claims, wherein the fat content of the low fat milk is in the range of 0-2 w%.

8. The method according to any one of the preceding claims, wherein the cream has a fat content in the range of 38-42 w%.

9. The method according to any one of the preceding claims, wherein in thestep of concentrating the cream, the cream is concentrated to a total solids content in the range of 55-80 w%, such as 65-80 w%, preferably 75-78 w% of the concentrated cream.

10. The method according to anyone of the previous claims, wherein in the step of mixing the concentrated low fat milk and the concentrated cream the ratio of solids content of the concentrated cream to concentrated low fat milk is in the range of 1:5 to 1:2.5, preferably 1:4.1 to 1:2.9.

11. The method according to anyone of the previous claims 2 to 10, wherein in the step of drying the homogenized whole milk concentrate, the homogenized whole milk concentrate is dried to obtain a whole milk powder with a total solids content of least 90 w%, preferably at least 95 w%, more preferred at least 97 w% of the whole milk powder.

12. The method according to any one of the preceding claims, wherein in the step of drying the optionally homogenized whole milk concentrate, the whole milk concentrate is dried by spray drying or roller-drying.

13. The method according to any one of the preceding claims wherein the fat reduced fraction is combined with the low fat milk before the concentration step.

14. A system for producing a high solids whole milk concentrate or powder, the system comprising a concentration unit (101), a centrifuge (102), a mixer (103), an optional homogenizer (104), and a spray dryer (105), wherein the concentration unit (101) has an inlet (101_i or 101a_i) for receiving skim milk and an outlet (101_o, 101b_o or 101c_o) for discharging a concentrated low fat milk; the centrifuge (102) has an inlet (102a) configured for receiving a cream and a first outlet (102b) for discharging a concentrated cream and a second outlet (102c) for discharging a fat reduced fraction; optionally the second outlet (102c) for discharging the fat reduced fraction is fluidly connected to the inlet (101_i or 101a_i) of the concentration unit, the mixer (103) is fluidly connected to the outlets of the concentration unit (101a_o, 101b_o or 101c_o) and the centrifuge (102b) and has an outlet (103z) for discharging a whole milk concentrate; the spray dryer (105) has an inlet (105a) fluidly connected to the outlet of the mixer (103), when present the optional homogenizer (104) has aninlet (104a) for receiving the whole milk concentrate from the mixer (103) and an outlet (104b) for discharging a homogenized whole milk concentrate, and the spray dryer (105) has an inlet (105a) fluidly connected to the outlet (104b) of the homogenizer (104).

15. The system according to claim 14, wherein the concentration unit (103) is a falling film evaporator (101); a reverse osmosis unit (101a) fluidly connected to a falling film evaporator (101b); or a reverse osmosis unit (101a) fluidly connected to a falling film evaporator (101b) and / or an agitated film evaporator (101c).

16. The system according to claim 14 and / or 15, wherein the second outlet (102c) for discharging the fat reduced fraction is fluidly connected to the inlet (101_i or 101a_i) of the concentration unit.

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