NZ712773B2

NZ712773B2 - Process and system for preparing dry milk formulae

Info

Publication number: NZ712773B2
Application number: NZ712773A
Authority: NZ
Inventors: Jitti Chiaranaipanich; Antonius Hendricus Janssen; Raoul Charles Johan Moonen; Olivier Bertrand Rabartin; John Tobin; Der Hoeven Martijn Johannes Van; Rudolph Eduardus Maria Verdurmen
Original assignee: Nv Nutricia
Priority date: 2013-04-03
Filing date: 2014-04-03
Publication date: 2021-05-27

Abstract

The present invention relates to a process and system for obtaining a dry milk formula, comprising the steps of (a-i) ultrafiltration of an animal skim milk composition comprising 70 - 90 wt% casein and 10 - 30 wt% whey proteins, based on total protein, and (a-ii) ultrafiltration of an animal whey composition comprising 0 - 25 wt% casein and 75 - 100 wt% whey proteins, based on total protein; or (a-iii) ultrafiltration of a mixture of the compositions of (a-i) and (a-ii), (b) preferably combining of the UF retentate originating from step (a-i) with the UF retentate originating from step (a-ii); (c) removing polyvalent ions from the UF permeate originating from step (a-i) and/or (a-ii) or (a-iii) to obtain at least one softened UF permeate; (d) combining the at least one softened UF permeate originating from step (c) with a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) to obtain a combined product; and (e-i) drying the combined product originating from step (d) to obtain a dry milk formula, and/or (e-ii) drying any UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) which is not combined in step (d), and drying any of the softened UF permeates originating from step (c) which is not combined in step (d), followed by combining the dried UF retentate with the dried softened UF permeate to obtain a dry milk formula. omposition comprising 0 - 25 wt% casein and 75 - 100 wt% whey proteins, based on total protein; or (a-iii) ultrafiltration of a mixture of the compositions of (a-i) and (a-ii), (b) preferably combining of the UF retentate originating from step (a-i) with the UF retentate originating from step (a-ii); (c) removing polyvalent ions from the UF permeate originating from step (a-i) and/or (a-ii) or (a-iii) to obtain at least one softened UF permeate; (d) combining the at least one softened UF permeate originating from step (c) with a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) to obtain a combined product; and (e-i) drying the combined product originating from step (d) to obtain a dry milk formula, and/or (e-ii) drying any UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) which is not combined in step (d), and drying any of the softened UF permeates originating from step (c) which is not combined in step (d), followed by combining the dried UF retentate with the dried softened UF permeate to obtain a dry milk formula.

Description

/050202 Process and system for preparing dry milk formulae The present invention relates to an advanced process for treating animal skim milk and animal whey, preferably for the manufacture of dry milk formulae such as infant milk formulae and other nutritional products for infants, as well as a system designed to implement the process according to the invention.

Background of the invention Human milk is considered the ‘golden standard’ for infant ion. Processing animal milk, for example cow’s milk, to more resemble the composition of human milk is known in the art. Such processing is known in the art as ‘humanizing’ animal milk. The process of humanizing animal milk es changing the ratio of casein:whey proteins as found in animal milk (e.g. approximately 80:20 for cows’ milk) to the desired ratio for infant nutrition as found in human milk (preferably between 75:25 and 30:70). In on, the mineral content of animal milk is typically higher that the content found in human milk.

Thus humanization of animal milk also involves reducing of the l content.

Preparation of ts suitable for use in infant nutrition typically involves blending of s individually purifled components in the appropriate , either wet or dry. Current manufacturing processes require multiple dairy ingredients from intermediate suppliers, including skim milk or a concentrate thereof (including skim milk powder), demineralised whey or a trate thereof ding demineralised whey powder), whey protein concentrates or isolates (normally as powders), and pure grade lactose (typically in powder form) to formulate a nutritionally balanced infant formula.

WO 96/08155 describes a process for treating skim milk for the manufacture of cheese and milk powders, wherein whey proteins are removed from skim milk by microflltration and further treatment es ultraflltration.

US 5,503,865 discloses a process for treating skim milk, comprising microﬁltration or ultraflltration. The permeate f may be demineralised by for example ion exchange and/or electrodialysis in order to make it suitable to be used in baby products.

US 4497836 ses a process wherein whey is subjected to ultraflltration, and the permeate thereof is subjected to electrodialysis or ion exchange.

WO 3689 discloses a s wherein milk serum is subjected to ultraflltration, and the te thereof is subjected to diaflltration. The ultraflltration retentate is combined with the diaflltration retentate in the production of infant milk formulae, by mixing the combined product with milk powder.

EP 1133238 describes a process wherein animal milk is subjected to microflltration through a membrane having a porosity of 0.1 — 0.2 micrometer, after which the microﬁltration permeate comprising whey proteins is demineralised by electrodialysis. The l content of the electrodialyzed microflltration te is very low, and subsequent fortif1cation with minerals and trace elements is required to obtain an infant formula.

Summary of the invention It is an object of the present invention to provide an improved process for preparing or obtaining a dry milk formula wherein the amount of filtration and tion steps are reduced compared to existing methods, problems related to ne fouling are reduced and yield in obtaining lactose or milk proteins is improved. This object, wholly or in part, is 2O solved by the present invention according to the appended .

In general, the present invention relates to a process for obtaining a dry milk formula in which more optimal use is made of ﬁltration and separation technologies. In a preferred embodiment, the present invention relates to a s for obtaining a dry milk formula, preferably for obtaining a dry milk formula that can be further processed into an infant milk formula or a dry milk infant formula (for human infants). Preferably, the process of the present invention involves ultraflltration of animal skim milk and ultraflltration of animal whey followed by mixing of the ultraflltration retentates, which are enriched in milk proteins and whey ns respectively. Adding animal whey to animal skim milk alters the protein composition of the skim milk, thereby humanizing the skim milk to more le the n composition of human milk. Both animal skim milk and animal whey contain polyvalent ions, the contents of which are reduced in order to make the combination of animal skim milk and animal whey suitable as dry milk formulation for human consumption or as a nutritional formulation for feeding human infants. In a red embodiment, also monovalent ions are removed from the UF te and/or the UF retentate to sufﬁciently low levels such that the dry milk formula is adapted for feeding human infants. Thus, broadly worded, the present invention relates to a process for obtaining a dry milk formula comprising the steps of ultraf11trating of animal skim milk and animal whey, removing lent ions from at least one UF permeate, and combining the softened UF permeate with the UF retentate followed by a drying step to obtain the dry milk formula.

The s ing to the invention employs ultraflltration for fractioning of casein and whey proteins from lower molecular weight animal skim milk and animal whey tuents (e.g. soluble salts, lactose, non-protein nitrogen (NPN), organic acids). As such, neither the animal skim milk nor the whey require r softening or removal of monovalent ions to the extent which is ordinarily done in the art, in order to reduce the soluble salts content to a desirably low level, preferably sufﬁciently low for infant nutrition preparation. The process according to the invention circumvents the need for including ively softened or demineralized whey proteins or extensive softening or demineralization of liquid whey protein streams, or the need for externally adding large amounts of dry lline lactose for the cture of dry milk powder suitable for infant nutrition preparation, by employing ultraflltration of animal skim milk and animal whey which are combined in a preferred ratio to ze animal skim milk.

The lactose that is removed from both the animal skim milk and the animal whey as ultraflltration permeate is subjected to polyvalent ion removal and preferably monovalent ion removal, and used in the resulting dry milk formula. As such, the mineral content of the resulting formulation can be adapted to sufficiently low levels to enable infant nutrition preparation according to regulatory bodies (e.g. EU directive 2006/l4l/EC, US Food and Drug Administration 21 CFR Ch 1 part 107).

Consequently, the t invention relates to a process for obtaining a dry milk formula, comprising the steps of: (a-i) ultraflltration (UF) of an animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% whey proteins, based on total protein, and (a-ii) ultraflltration of an animal whey composition comprising 0 — 25 wt% casein and 75 — 100 wt% whey proteins, based on total protein; or (a-iii) ultraflltration of a mixture of the compositions of (a-i) and (a-ii); (b) preferably combining ofthe UF ate originating from step (a-i) with the UF retentate ating from step (a-ii); (C) removing polyvalent ions from the UF te originating from step (a-i) and/or (a-ii) or (a-iii) to obtain at least one softened UF permeate; (d) combining the at least one softened UF permeate originating from step (c) with a UF retentate originating from step (a-i) and/or ; or (a-iii) or (b) to obtain a combined product; and drying the combined product originating from step (d) to obtain a dry milk formula; and/or drying any UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) which is not ed in step (d); and drying any of the softened UF permeates originating from step (c) which is not combined in step ((1), followed by combining the dried UF retentate with the dried softened UF permeate to obtain a dry milk formula.

In another aspect; the present ion relates to a modular system for carrying out the process according to the invention; comprising: 2O (1) an ultraflltration module; comprising (1a) an inlet for ing a ﬁrst liquid composition as meant herein and/or a second liquid composition as meant herein; or a mixture thereof; to a ﬁrst side of an lltration membrane; (lb) the ultraflltration membrane; (lc) a ﬁrst outlet for discharging an ultraflltration retentate (UFR) from the ﬁrst side of the ultraflltration membrane; and (1d) a second outlet for discharging an ultraflltration permeate (UFP) from the second side of the ultraflltration membrane; (2) a polyvalent ion removal module; comprising (2a) an inlet for receiving the UFP originating from the lltration module (1), (2b) means for removing polyvalent ions; and (2c) an outlet for discharging a softened UFP; W0 2014/163493 (3) at least one mixing module, comprising (3 a) a ﬁrst inlet for receiving the softened UFP originating from the polyvalent ion removal module (2), (3bl) a second inlet for receiving the ﬁrst liquid ition or an UFR of the ﬁrst liquid composition and a third inlet for receiving the second liquid composition or an UFR of the second liquid, or (3b2) a second inlet for receiving the mixture of the ﬁrst liquid composition and the second liquid composition or an UFR of the ﬁrst liquid composition and an UFR ofthe second liquid composition, and (3c) an outlet for discharging a recombined product, and (4) a drying module, comprising (4al) a ﬁrst inlet for receiving the UFR originating from the ultraﬁltration module (1) and a second inlet for ing the softened UFP originating from the polyvalent ion removal module (2), or (4a2) an inlet for receiving the recombined product originating from the mixing module (3), (4b) drying means, and (40) an outlet for discharging a dried ition, wherein the ﬁrst liquid composition is an animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% 2O whey ns, based on total protein, and wherein the second liquid composition is an animal whey composition comprising 0 — 25 wt% casein and 75 — 100 wt% whey ns, based on total protein.

List of preferred embodiments The invention particularly pertains to: l . A s for obtaining a dry milk formula, comprising the following steps: (a-i) ultraﬁltration (UF) of an animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% whey proteins, based on total protein, and (a-ii) ltration of an animal whey composition comprising 0 — 25 wt% casein and 75 — 100 wt% whey proteins, based on total protein, or (a-iii) ultraﬁltration of a mixture of the compositions of (a-i) and (a-ii), (b) preferably ing of the UF retentate originating from step (a-i) with the UF retentate originating from step (a-ii), (c) removing polyvalent ions from the UF permeate originating from step (a-i) and/or (a-ii) or (a-iii) to obtain at least one softened UF permeate, (d) combining the at least one softened UF permeate originating from step (c) with a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) to obtain a combined product; and (e-i) drying the combined product originating from step (d) to obtain a dry milk formula, and/or (e-ii) drying any UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) which is not ed in step (d), and drying any of the softened UF permeates originating from step (c) which is not combined in step (d), followed by combining the dried UF ate with the dried softened UF permeate to obtain a dry milk formula. 2. The process according to 1, wherein the animal skim milk comprises 75 — 85 wt% casein and 15 — 25 wt% whey proteins, based on total protein, preferably about 80 wt% casein and about 20 wt% whey protein or the animal skim milk composition comprises or is selected from animal skim milk, diluted animal skim milk, concentrated animal skim milk, (optionally diluted) skim milk concentrate or reconstituted skim milk powder. 3. The s according to 1, n the animal whey composition comprises 0 — 20 wt% casein and 80 — 100 wt% whey proteins, based on total protein, preferably 0 — 10 wt% casein and 90 — 100 wt% whey proteins, more preferably 0 — 5 wt% casein and 95 — 100 wt% whey proteins or the animal whey ition comprises or is selected from animal whey, diluted animal whey, concentrated animal whey, (optionally diluted) animal whey concentrate and tituted animal whey powder. Preferably, the animal whey is or comprises sweet whey and/or acid whey, preferably the animal whey is sweet whey. 4. The process according to any one of l — 3, wherein a UF te originating from step (a-i) and a UF permeate ating from step (a-ii) are combined prior to said removal of polyvalent ions of step (c).

. The process according to any one of l — 4, wherein a UF retentate originating from step (a-i) and/or (a-ii) is/are concentrated prior to the combining of step (b), (d) or drying of step (e-i) and/or (e-ii), and/or a UF retentate ating from step (a-iii) and/or (b) is/are concentrated prior to the combining of step (d) or drying of step (e-i) and/or (e-ii), ably by nanoflltration. 6. The s according to any of 1-5, wherein the UF permeate originating from step (a-i) is combined with a permeate ating from (a-ii) prior to polyvalent ion removal of step (c), and preferably concentrated after polyvalent ion removal of step (c). 7. The process according to any of 1-6, wherein the softened UF te originating from step (c) and/or the combined product of step (d) is/are concentrated, prior to the combining of step (d) or the drying of step (e-i) and/or (e-ii). 8. The process according to any of 5-7, wherein concentration occurs by reverse osmosis and/or nanofiltration. 9. The process ing to any one of l — 8, wherein polyvalent ion removal of step (c) occurs by electrodialysis, ion exchange, lactose crystallization and/or salt precipitation, more preferably by a combination of nanoflltration, salt precipitation, ultraflltration and electrodialysis, most preferably following the sequence of nanoflltration, salt precipitation, ultrafiltration and electrodialysis.

. The process according to any one of l — 9, wherein the softened UF permeate of step (c) and/or the UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) is/are subjected to monovalent ion removal, preferably by electrodialysis, ltration, lactose crystallization and/or salt precipitation. 11. The process according to any one of l — 10, wherein a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) and/or a UF permeate originating from step (a-i) and/or (a-ii) or ), and/or the softened UF permeate originating from step (c) or the combined t of step (d) is/are heat-treated, preferably heat-sterilized by DSI, prior to the drying of step (e-i) and/or (e-ii), preferably the combined product of step (d) is heat- treated, preferably by DSI, prior to the drying of step (e-i), or preferably any of the UP retentates of step (e-ii) and/or any of the softened UF permeates of step (e-ii) is heat-treated, ably by DSI, prior to the drying of step (e-ii). 2014/050202 12. The process according to any one of 1 — 11, wherein drying of step (e-i) and/or (e-ii) is by spray-drying. 13. The process ing to any one of 1 — 12, wherein the combined product ating from step (d), the dried combined product of (e-i), and/or the dried UF retentate of (e-ii) which is combined with the dried softened UF permeate of (e-ii) in step (e-ii) is further sed into a nutritional product for providing nutrition to infants. Preferably, to the combined product originating from step (d) is/are added suitable amounts of fat or oils, dietary ﬁber, optionally additional lactose, vitamins and optionally onal minerals. 14. The process according to any one of 1 — 13, wherein the animal skim milk composition and animal whey composition of step (a-iii) or the UF retentates originating from step (a-i) and (a-ii) are combined in such a ratio that a product is obtained having a :whey protein weight ratio of between 75:25 to 30:70, preferably between 64:36 to 36:64, more preferably 60:40 to 40:60 or about 50:50.

. The process according to any one of 1 — 13, wherein the mixture of the animal skim milk composition and animal whey composition of step (a-iii) or the combined UF retentate of step (b), or the combined product of step (d), the dry milk formula of (e-i) or the dry milk formula of (e-ii) has a casein:whey protein weight ratio of between 75:25 and 30:70, more preferably between 70:30 and 35:65, most preferably between 64:36 and 36:64 or about 50:50. 16. The process according to any one of 1 — 15, n the at least one softened UF permeate of step (c) is obtained in a single polyvalent ion removal step or treatment. 17. The process according to any one of 1 — 16, wherein any UF retentate originating from step (a-i) and/or , or step (a-iii) or step (b) is ted to a maXimum of two or preferably only one concentration and/or lent ion removal step and preferably to one or no polyvalent ion removal step before being subjected to the (e-i) or (e-ii) drying step. 18. The process according to any one of 1-7, n a UF permeate ating from step (a-i) and a UF permeate originating from step (a-ii) are combined prior to said combining in step (d), or preferably combined prior to the removal of polyvalent ions of step (c). 19. The process according to any one of 1 — 18, wherein the UF permeate originating from step (a-i) and the UF permeate originating from step (a-ii) are combined in a volume ratio of between 10:1 and 1:20, preferably 5:1 and 1:15, more preferably 1:1 and 1:10, most preferably between 1:2 and 1:6. 20. The process according to any one of 1 — 19, wherein the mixture of step (a-iii) is obtained by combining the animal skim milk composition and the animal whey composition in a volume ratio of between 10:1 and 1:10, ably 6:1 and 1:6, more preferably 3:1 and 1:3 or wherein the combining in step (b) comprises ing the UF permeate originating from step (a-i) with the UF permeate originating from step (a-ii) in a volume ratio of between 10:1 and 1:10, preferably 6:1 and 1:6, more preferably 3:1 and 1:3. 21. The process according to any one of 1 — 20, wherein the UF retentate ating from step (a-i), , (a-iii) and (b) are enriched for casein and whey proteins compared to the ﬁrst animal skim milk and second animal whey compositions, and/or the UF permeate originating from step (a-i), (a-ii) and (a-iii) is enriched for lactose compared to the ﬁrst animal skim milk and second animal whey compositions. 22. The process according to any one of 1 — 21, wherein the ultraf11tration, polyvalent ion removal step, monovalent ion removal step, any concentration step and/or any combining step is performed at a temperature below 40 0C, more preferably between 3 oC and 30 oC even more ably n 5 oC and 20 oC, most preferably between 8 and 12 oC. Higher temperatures may increase the risk of spoilage of the dairy products, and lower temperatures may give rise to freezing of the liquid streams, which are both undesirable. 23. The process according to any one of 1 — 22, n the process operates with 500 — 2500 kg, more preferably 800 — 1800 kg, most preferably 1000 — 1400 kg dry matter of the animal skim milk composition incoming per hour. 24. The process ing to any one of 1 — 23, wherein the process according to the invention operates with 1500 — 5000 kg, more preferably 2200 — 4000 kg, most preferably 2600 — 3000 kg dry matter of the animal whey composition, incoming per hour.

. The process according to any one of 1 — 24, wherein the process according to the invention preferably es with 750 — 4000 kg, more preferably 1000 — 3000 kg, most preferably 1500 — 2000 kg UF ate obtained per hour from the ultraf11tration of (a-i) and (a-ii) or (a-iii). 26. The process according to any one of 1 — 25, wherein the process according to the invention preferably operates with 1000 — 5000 kg, more ably 1500 — 4000 kg, most preferably 2000 — 2500 kg UF permeate obtained per hour from the ultraf11tration of (a-i) and (a-ii) or (a-iii). 27. The process according to any one of 1 — 26, wherein the 11tration of step (a-i) is operated using a volume concentration factor of 1.5 — 6, preferably 1.7 to 4, more ably 1.8 to 3, most preferably about 2, and the ultraf11tration of step (a-ii) is operated using a volume concentration factor of 2 — 15, preferably 3 - 10, more preferably 4 — 7, most preferably about 5 and the 11tration of step (aii-i) is operated using a volume tration factor of 1.5 — 10, ably between 2 and 8, more preferably between 3 and 6, most preferably about 4. 28. The process according to any one of 1 — 27, wherein at least 10 or 20 wt% of the polyvalent ions that are present in said UF permeate (on dry weight basis thereof) is removed, preferably at least 50 wt%, 60 wt%, more preferably 70 wt% or at least 80 wt%, most preferably at least 90 wt%. 29. The process according to any one of 1 — 28, wherein monovalent ion removal comprises removal of at least 10 or 20 wt% (on dry weight basis) of the monovalent ions from the composition which was subjected to a monovalent ion removal step, more preferably at least wt% or 50 wt%, most preferably at least 60 wt%. 2014/050202 . The s according to any one of l — 29, wherein the mixture of (a-iii) comprises a casein:whey protein ratio of between 75:25 and 30:70, more preferably between 70:30 and :65, most preferably between 64:36 and 36:64 or about 50:50.

Detailed description of the invention Present day manufacturers of dry milk (infant) nutritional compositions largely rely on supply and use of highly purified ingredients, such as purif1ed lactose, demineralized whey proteins and minerals, to produce said compositions by mixing these sourced ingredients.

The present inventors have designed a process for treating animal skim milk and animal whey for manufacturing dry dairy products, in particular dry milk formulations, which largely circumvents buying such high-grade, pure ingredients from third parties.

The s of the t invention has several advantages over existing methods of producing dry milk ae, e. g. the loss in lactose yield and whey during the processing of skim milk and whey is reduced (e.g. during conventional demineralization of whey and crystallization of lactose), cations related to fouling of membranes and tion of protein material are reduced, the use of (externally added) chemicals is d and waste water may be recycled in the s to a large extent. As such, the amount of waste and waste streams is reduced compared to the conventional process. In addition, the need for energy consuming drying, softening and demineralization steps is d. More in particular, whereas lactose yield in conventional puriﬁcation methods for the production of dairy products lies around 83-85%, the lactose yield can be improved to over 90% in the process of the present invention. Hence, the process according to the invention has a lower environmental impact compared to the conventional process for producing dairy ts such as dry formulae or milk powders, in particular nutritional products for feeding infants.

The process according to the invention employs two incoming liquid compositions (i.e. step (a-i) and (a-ii)), the first thereof is an animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% whey proteins, based on total n, and the second thereof is an animal whey composition being comprising 0 — 25 wt% casein and 75 — 100 wt% whey proteins, based on total protein. At one point in the process, the first and second liquid compositions are combined or mixed. This combining or mixing may occur prior to ultraflltration, such that the ultraflltration of step (a-iii) is performed on a mixture of the first and the second liquid composition. Alternatively, the combining or mixing may occur after 11tration, such that ultraflltration is performed on the first liquid composition in step (a- i) and the second liquid composition in step (a-ii).

In a ﬁrst advantageous embodiment, the present invention relates to a process for obtaining a dry milk formula, n preferably a single ultraflltration step is conducted, comprising the following steps: (a-iii) ultraf11tration of a mixture of an animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% whey proteins, based on total protein, and an animal whey composition comprising 0 — 25 wt% casein and 75 — 100 wt% whey proteins, based on total protein, (c) ng polyvalent ions from the UF permeate originating from step (a-iii) to obtain a softened UF permeate, (d) combining the softened UF permeate originating from step (c) with a UF retentate originating from step (a-iii) to obtain a combined product, and (e-i) drying the combined product originating from step (d) to obtain a dry milk formula.

In this first advantageous embodiment, the ratio of casein to whey protein can be inﬂuenced by ing the volume ratio of the animal skim milk composition the animal whey composition to be ultraf11trated. Thus, in this embodiment, preferably the animal skim milk composition and animal whey composition of step (a-iii) are combined in such a ratio that a UF retentate product is obtained having a casein:whey n weight ratio of n 75:25 to 30:70, preferably between 64:36 to 36:64, more preferably 60:40 to 40:60 or about 50:50.

Preferably, a volume ratio of n 10:1 and 1:10, preferably 6:1 and 1:6, more preferably 3 :1 and 1:3 of the animal skim milk ition to the animal whey composition is used to achieve this end. This UF retentate product is preferably subjected to a concentration and/or monovalent ion removal step before being combined with the softened permeate in step (d). ably, this UF retentate product is subjected to a single concentration step (e.g. reverse osmosis and/or nanof11tration) during which also monovalent ions are removed before being combined with the ed permeate in step (d).

Furthermore, in this first advantageous embodiment, removing polyvalent ions in step (c) to obtain a softened UF te, is followed by a monovalent ion removal step (preferably by WO 63493 a nanofiltration and/or diaflltration step) before combining in step (d) takes place. This is especially preferred when ion exchange against monovalent ions is used for softening. The lactose enriched, softened UF permeate may be subjected to one, two or three nanoflltration and/or reverse osmosis steps to remove sufﬁcient monovalent ion amounts when preparing a dry milk formulation usable for feeding a human infant. rmore, in this first advantageous embodiment, ultrafiltration of step (aii-i) is operated using a volume concentration factor of 1.5 — 10, preferably n 2 and 8, more preferably between 3 and 6, most preferably about 4.

In a second ageous embodiment, the invention relates to a process for obtaining a dry milk formula, comprising the following steps: (a-i) ultraflltration (UF) of an animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% whey proteins, based on total protein, and (a-ii) ultraflltration of an animal whey composition comprising 0 — 25 wt% casein and 75 — 100 wt% whey proteins, based on total protein, (b) preferably combining of the UF retentate originating from step (a-i) with the UF retentate originating from step (a-ii), (c) removing polyvalent ions from the UF permeate originating from step (a-i) and/or 2O (a-ii) to obtain at least one softened UF permeate, (d) ing the at least one softened UF permeate originating from step (c) with at least a UF retentate originating from step (a-i) and/or , or (b) to obtain a combined product, and (e-i) drying the combined product ating from step (d) to obtain a dry milk formula, and/or (e-ii) drying any UF retentate originating from step (a-i) and/or (a-ii) or (b) which is not combined in step (d), and drying any of the softened UF permeates originating from step (c) which is not combined in step (d), followed by combining the dried UF ate with the dried softened UF permeate to obtain a dry milk formula.

In this second advantageous ment, the ratio of casein to whey n can be inﬂuenced by selecting the volume ratio ofUF retentate originating from (a-i) and (a-ii), either in step (b) or in step (d) or (e-ii). Thus, in this embodiment, preferably the UF retentates ating from step (a-i) and (a-ii) are combined in such a ratio that a UF retentate product is obtained having a casein:whey protein weight ratio of between 75:25 to :70, preferably between 64:36 to 36:64, more preferably 60:40 to 40:60 or about 50:50.

Preferably, a volume ratio of between 10:1 and 1:10, preferably 6:1 and 1:6, more preferably 3 :1 and 1:3 of the UP retentates originating from step (a-i) and (a-ii) is used to achieve this goal. The UF retentates originating from (a-i) and/or (a-ii) or (b) is/are preferably ted to a tration and/or monovalent ion removal step before being combined with the softened te in step (d). Preferably, any or all of these UF retentates are subjected to a single concentration step (e.g. reverse osmosis and/or nanoflltration) during which also monovalent ions are removed before being combined with the softened permeate in step (d).

Furthermore, in this second advantageous embodiment, removing polyvalent ions in step (c) to obtain a softened UF permeate, is followed by a monovalent ion removal step (preferably by a nanof11tration and/or diaflltration step) before combining in step (d) takes place. This is especially preferred when ion ge against lent ions is used for softening. The lactose enriched, softened UF permeate may be subjected to one, two or three nanoflltration and/or reverse osmosis steps to remove sufﬁcient monovalent ion amounts when ing a dry milk formulation usable for feeding a human .

In a preferred version of this second advantageous embodiment, the UP retentates originating from (a-i) and (a-ii) are (individually or separately) subjected to a concentration and/or monovalent ion removal step prior to ing in step (b). Next, the thus treated and combined UF retentate is combined in step (d) with a softened permeate originating from (c). Preferably, the softening in this step (c) involves removing polyvalent ions from a single UF permeate originating from combining the permeates originating from (a-i) and (a- ii) to obtain one softened UF permeate.

In an ative , a process for treating animal skim milk and animal whey is mentioned , sing: (a) ultraflltration (UF) of a mixture of animal skim milk and animal whey (sweet and/or acid whey) over an ultraflltration membrane having a molecular weight cut-off of 2.5 — 25 kDa using a volume concentration factor of 1.5 — 10, preferably between 2 and 8, more preferably between 3 and 6, most preferably about 4, and obtaining a retentate and a permeate. Optionally, polyvalent ions are removed from the UF permeate originating from step (a) after which the softened UF permeate is preferably subjected to a concentration and/or monovalent ion removal step. Optionally, also the UF retentate is subjected to a concentration and/or monovalent ion removal step. Preferably, the softened UF permeate, which preferably also has undergone monovalent ion removal, is mixed with the UP retentate originating from step (a), which UF retentate may or may not have undergone concentration and/or monovalent ion removal, to obtain a mixture. Said e is preferably dried to a dry milk formula. Preferably, the e of animal skim milk and animal whey comprises a casein:whey protein ratio of between 75:25 and 30:70, more preferably between 70:30 and 35:65, most preferably between 64:36 and 36:64 or about 50:50.

Deﬁnitions The term "animal whey" herein refers to the liquid by-product obtained from the cheese- making industry. The term “whey protein” refers to proteins that are present in said animal whey, such as sweet whey or acid whey. Typically, whey proteins include, i.a. beta- lactoglobulin, alpha-lactalbumin, bovine serum albumin, immunoglobulins, lactoferrin, lactoperoxidase and/or glycomacroprotein.

The term “sweet whey” herein refers to the liquid (whey protein containing) by-product of the cheese manufacture industry which makes use of enzymatic cheese curd formation (e. g. based on casein precipitation using rennet), which material is readily accessible in the commercial market. lly, whey proteins present in sweet whey include, i.a. beta- lobulin, alpha-lactalbumin, bovine serum albumin, immunoglobulins, lactoferrin, lactoperoxidase and glycomacroprotein Conversely, the term “acid whey” herein refers to the liquid (whey n containing) by- t of the cheese cture industry which makes use of (edible) acids for cheese curd formation (e.g. based on casein precipitation using acids such as citric acid), which al is y accessible in the commercial market. Typically, whey proteins present in acid whey include, i.a. actoglobulin, alpha-lactalbumin, bovine serum albumin, globulins, lactoferrin and lactoperoxidase The term n" herein refers to casein or caseinate proteins as found in animal skim milk, such as bovine skim milk, more in particular cows' skim milk. Preferably, casein or caseinate is in substantially intact, non-hydrolyzed form.

By a “UF retentate originating from” is meant the liquid retentate composition that is (directly) obtained from ultraflltration steps (a-i), (a-ii) and (a-iii). The term also refers to the UF retentates that are conveyed as (liquid) compositions from the ultraflltration step to the optional combining step (b) or the ing with a softened UF te in step (d) to obtain the combined permeate/retentate product or drying in step (e-ii). Irrespective of whether between the obtaining of the UF retentate from step (a-i), (a-ii) or (a-iii) and the combining in step (d) or drying in step (e-ii), the UF retentate is ted to a concentration step, such as reverse osmosis or nanoflltration, the term UF retentate still applies to this UF fraction. Thus, the term UF retentate is meant to denote the (protein enriched) fraction that is processed ing to the steps of the invention from the ultraflltration step up to the point where it is (re)combined with a UF permeate. rly, the term “UF permeate originating from” herein means the liquid permeate composition that is (directly) obtained from ultraflltration steps (a-i), (a-ii) and (a-iii). The term also refers to the UF permeates that are conveyed as (liquid) compositions from the ultraflltration step to the polyvalent ion removal module, optional means for removing monovalent ions and/or optional concentration module to eventually obtain the combined te/retentate product of (d) or to the drying module for drying in step (e-ii).

Irrespective of whether between the obtaining of the UF permeate from step (a-i), (a-ii) or ) and the combining in step (d) or drying in step (e-ii), the UF permeate is subjected to a processing step (e.g. a polyvalent ion removal step, a concentration step, reverse osmosis and/or nanoflltration), within the context of the present invention the term UF permeate still applies to this UF on. Thus, the term UF permeate is meant to denote the (lactose ed) fraction that is processed according to the steps of the invention from the ultraflltration step up to the point where it is mbined with a UF retentate.

As used herein, the term alent ions” refers to ions having a positive or negative charge of two or more. More in particular, this term refers to Mg2+, Ca2+ and polyvalent phosphate anions (e.g. HPO42', PO43) The term “monovalent ions” refers to ions having a positive or negative charge of one, in particular Na+, K+, Cl'.

The term al of polyvalent ions” means that said polyvalent ions are removed from the UP te composition which is ted to the polyvalent ion removal step (step (c)). Preferably, the term “removal of lent ions” indicates that at least 10 or 20 wt% of the polyvalent ions that are present in said UF permeate (on dry weight basis thereof) is removed, preferably at least 50 wt%, 60 wt%, more preferably 70 wt% or at least 80 wt%, most preferably at least 90 wt%. The weight percentage (wt%) of polyvalent ion removal is determined by comparing the total weight of polyvalent ions present after step (c) to the total weight of polyvalent ions present prior to step (c). Likewise, the term “softening” is used to denote the removal of polyvalent ions. Hence, herein “softening” and “removal of polyvalent ions” is used interchangeably. Analogously, the term “softened” is used to refer to a composition from which polyvalent ions have been removed. Preferably, the term “softened” means that at least 10 or 20 wt% (on dry weight basis) of the polyvalent ions is removed from the ition by polyvalent ion removal, preferably at least 50 wt% or 60 wt%, more preferably 70 wt% or 80 wt%, most preferably at least 90 wt%. “Signif1cant polyvalent ion removal” denotes the removal of at least 70 wt% of the polyvalent ions, preferably at least 85 wt%, more preferably at least 95 wt% or even at least 99 wt% of the polyvalent ions. Polyvalent ion l or softening may be accompanied with monovalent ion l, either in the same step or in a separate step. Preferably, polyvalent ion removal refers to removal of at least or all of calcium, magnesium and/or phosphate s to the extent as deﬁned in this paragraph.

The term “removal of monovalent ions” means that said monovalent ions are removed from the composition which is subjected to the monovalent ion removal step (preferably a softened UF permeate and/or any UF retentate). In case not indicated otherwise, preferably at least 10 or 20 wt% (on dry weight basis) of the monovalent ions is removed from the ition which was subjected to a lent ion removal step, more preferably at least 35 wt% or 50 wt%, most preferably at least 60 wt%. Removal of monovalent ions is particularly preferred in case the process according to the ion aims to manufacture dry powder formulations intended for use as infant nutrition. “Signif1cant monovalent ion removal” denotes the removal of at least 70 wt% of the monovalent ions, preferably at least 85 wt%, more preferably at least 95 wt% or even at least 99 wt% of the monovalent ions.

Preferably, monovalent ion removal refers to removal of at least or all of sodium, potassium and/or chloride to the extent as defined in this paragraph.

The “total solid content” of a liquid composition denotes the weight percentage of solids present in the composition, based on the total weight of the composition. Solids include all non-volatiles, typically everything except water.

The term “enriched” herein refers to the situation wherein the amount of a certain constituent in a (liquid) composition (as wt% based on dry weight) is higher after a s step, when compared to the t of the same ingredient in the (liquid) composition before said process step. Preferably, the dry weight percentage of an ingredient that is ed has a content in a stream discharged from the process step of at least 110 %, more preferably at least 125%, most ably at least 150 %, based on the dry weight percentage of said ingredient in the incoming stream of said process step. Exemplary is the ultraflltration of animal skim milk, wherein the milk proteins are ed in the retentate while water and small s permeate through the ultraflltration membrane. As such, the UF retentate is enriched in milk proteins, as the t of milk proteins in the retentate, as wt% based on dry weight of the composition, is sed compared to the wt% of milk proteins in skim milk. Likewise, the UF permeate is enriched in small solutes (preferably lactose), as the amount of proteins is significantly reduced in the permeate, and e constitutes by far the largest part of the dry weight of the permeate.

The term “dry milk formula” refers to a dry powder which at least comprises milk proteins, in particular casein and whey, and minerals which is obtained by drying animal skim milk and animal whey and is intended for human consumption. As such, the milk formula is dried and has a water content of between 0.5 and 5 wt%, based on total weight of the formula, preferably n 1 and 4 wt% or 1.5 and 3.5 wt%. The term “dry milk infant formula” herein refers to a dry milk formula which is adapted for feeding human infants.

The term “volume concentration factor” or “VCF” is the factor at which a liquid composition is concentrated upon flltration, i.e. the total volume of the incoming stream prior to ﬁltration divided by the total volume of the retentate after ion, irrespective of the total solid content. Thus, when 5 L of a liquid composition is fractionated over an ultraﬁltration membrane into a permeate of 4 L and a retentate of l L, this UF process operates with a VCF of 5/1 = 5.

The term “about” indicates a variation (plus and minus) of 10 % of the given value, more preferably 5%.

First liquid composition (animal skim milk) and second liquid composition (animal whey) The process according to the invention uses at least two sources of milk protein, lactose and minerals, the ﬁrst being a (liquid) animal skim milk composition comprising 70 — 90 wt% casein and 10 — 30 wt% whey proteins, based on total protein and the second being a (liquid) animal whey ition comprising 0 — 25 wt% casein and 75 — 100 wt% whey proteins, based on total protein.

The ﬁrst liquid composition is an animal skim milk ition which comprises milk proteins and lactose. It comprises s of minerals that are typical for animal skim milk (in the form of monovalent and polyvalent ions). The protein fraction of the ﬁrst liquid composition comprises 70 — 90 wt% casein and 10 — 30 wt% whey proteins, preferably 75 — 85 wt% casein and 15 — 25 wt% whey protein, most preferably 80:20 wt% casein to whey n, based on dry total weight of the protein fraction. Preferably, the ﬁrst liquid composition comprises 20 — 60 wt% protein, more preferably 25 — 50 wt% n based on total dry weight of the ﬁrst liquid composition. Preferably, the ﬁrst liquid composition comprises 25 — 75 wt% e, more preferably 40 — 60 wt% lactose, based on total dry weight of the ﬁrst liquid composition. Preferably, the ﬁrst liquid composition comprises 3 — 15 wt% minerals, more preferably 5 — 10 wt% minerals, based on total dry weight of the ﬁrst liquid composition. Preferably, the ﬁrst liquid ition comprises 25 — 75 wt% monovalent ions, more preferably 40 — 70 wt% monovalent ions, and 25 — 75 wt% polyvalent ions, more preferably 30 — 60 wt% polyvalent ions, based on total dry weight of the minerals. Preferably, the ﬁrst liquid composition has a total solid content between 3 and 15 %, more preferably between 6 and 11 %, most ably between 7.5 and 10 %. The fat content of the animal skim milk is typical for animal skim milk and lies well below that of non-skim milk. In ular, the fat content lies below 3 wt% (g/100g animal skim milk), preferably below 2 wt%, more ably below 1 wt%, most preferably below 0.5 wt%.

WO 63493 In an especially red embodiment, the first liquid composition comprises animal skim milk or is animal skim milk. Animal skim milk (i.e. non-human skim milk), preferably from bovine animals, and may be used as such, in diluted or concentrated form, as (optionally diluted) skim milk trate or as reconstituted skim milk powder. Most preferably, the ﬁrst liquid composition is cows’ skim milk. The animal skim milk may be pretreated before it is subjected to the process according to the invention. Such pre-treatment comprises or consists of a heat-treatment step (e.g. pasteurization) and/or tion step to reduce the bacterial load of the animal skim milk. Preferably, the animal skim milk is not pre-treated with the aim to change the mineral content or e thereof In ular, the animal skim milk is preferably not (signiﬁcantly) softened or subjected to monovalent ion removal before it enters the present ultraf11tration process.

The second liquid is an animal whey composition which comprises n, lactose and amounts of minerals that are typical for animal whey (in the form of monovalent and polyvalent ions). The protein fraction of the liquid animal whey composition comprises 0 — wt% casein and 75 — 100 wt% whey proteins, preferably 0 — 10 wt% casein and 90 — 100 wt% whey protein, most preferably 0 — 5 wt% casein and 95 — 100 wt% whey protein, based on dry total weight of the protein fraction. Preferably, the animal whey composition 2O comprises 5 — 40 wt% protein, more ably 7 — 17 wt% protein based on total dry weight of the second liquid composition. Preferably, the animal whey composition comprises 40 — 90 wt% lactose, more preferably 60 — 80 wt% lactose, based on total dry weight of the second liquid composition. Preferably, the animal whey composition comprises 3 — 15 wt% minerals, more preferably 6 — 12 wt% ls, based on total dry weight of the second liquid composition. ably, the animal whey composition comprises 40 — 90 wt% monovalent ions, more preferably 60 — 85 wt% monovalent ions, and 10 — 60 wt% polyvalent ions, more preferably 15 — 40 wt% polyvalent ions, based on total dry weight of the minerals. Preferably, the animal whey composition has a total solid content n 1 and 15 %, more preferably between 3 and 10 %, most preferably between 4 and 8 %.

The animal whey is derived from making cheese wherein any non-human (skim) milk is used, preferably from bovine skim milk, most preferably cows’ milk. Animal whey may be used as such, in diluted or concentrated form, as (optionally diluted) animal whey concentrate and as reconstituted animal whey from a powder. Both sweet whey and acid whey are suitable as liquid animal whey composition for use in the invention. Most ably, the second liquid composition is sweet whey. The animal whey as used may be pretreated before it is subjected to an ultraflltration step of the process ing to the invention. Pre-treatment of the animal whey comprises or consists of heat-treatment (preferably pasteurization) and/or ﬁltration to reduce the ial load of the animal whey.

Preferably, the animal whey is not pre-treated with the aim to change the mineral content or profile thereof. In particular, the animal whey is not (signiﬁcantly) softened or subjected to monovalent ion removal before it enters the t process.

Any pretreatment of animal skim milk or animal whey is primarily not preferred from a cost perspective: any such step is likely to increase the price of these liquid compositions, while the process of the invention is designed such that it is capable of processing these liquid compositions t any costly pretreatment step into a dry milk formulation.

Ullraflltralion (UF) step (cl-l), 1), (cl-iii) In the process according to the invention, the ﬁrst animal skim milk composition and the second animal whey composition are subjected to a UF step: (a-i) and (a-ii) or (a-iii). Herein water and small solutes can permeate through the membrane to end up in the UF permeate 2O (UFP), while the UF retentate (UFR) comprises substantially all protein, which can be stated to be enriched in proteins. Small molecules which are able to permeate through the UP membrane include lactose, NPN, monovalent ions and polyvalent ions. Thus, the UFP can be stated to be enriched in lactose.

The ultraflltration of step (a) may employ any UF membrane known in the art, including ceramic membranes, tubular and organic spiral wound membranes, preferably the UP membrane is an organic spiral wound ne. The UF ne has a molecular weight cut-off (MWCO) of that enables proteins (e.g. whey proteins and casein) to remain in the retentate, and allow small solutes (e. g. solutes having a molecular weight of at most 25 kDa, preferably at most 10 kDa) to permeate through the membrane. Preferably, the molecular weight cut-off is at most 25 kDa, more ably at most 10 kDa, and ably of at least 2.5 kDa, more preferably at least 5 kDa.

In a preferred embodiment, the lltration involves steps (a-i) and (a-ii), which are separately performed on the first liquid composition and the second liquid ition respectively, and preferably followed by combining of the UF retentates originating thereform in step (b). Said combining or mixing in step (b) provides a (combined) UF retentate of which the protein composition is altered in the sense that the casein to whey n weight ratio is reduced. The (weight or volume) ratio in which the UF retentates originating from steps (a-i) and (a-ii) are ed is dependent on the exact protein composition of the incoming first liquid composition but is mainly determined by the desired protein composition in the resulting UF retentate and/or the resulting dry milk formula. The skilled person is able to determine the protein composition and concentration ofthe incoming ﬁrst liquid composition or the UP retentate thereof by methods known in the art, e.g. by the method ing to FT001/IDF 20-3 (for total protein, N * 6.38), IDF29- l/ISOl7997-l:2004 (for casein) and FT003 (for whey, NCN, non-casein nitrogen * 6.38).

The exact protein composition of incoming ﬁrst liquid composition (animal skim milk), or the UF retentate thereof, may vary between ent s, but even skim milk from the same animal (e.g. cow) may exhibit limited seasonal variations. In a particularly preferred embodiment, the dry milk formula is further processed into a nutritional product for human s such as infant ae, weaning infant formulae, follow up milk or formulae, g-up milk or toddler milk. In this respect, the resulting weight ratio of casein:whey protein after mixing is preferably n 75:25 and 30:70, more preferably between 70:30 and 35:65, most ably between 64:36 and 36:64 or about 50:50.

In case ultraflltration is by step (a-i) and (a-ii), mixing of the UF retentate originating therefrom may be performed on liquid streams thus giving a liquid mixture. Alternatively, the UF retentate originating from step (a-i) and (a-ii) is subjected to drying of step (e-i) and (e-ii) prior to mixing, and a liquid composition and a solid composition are mixed (e. g. by dissolving the solid in the liquid) to obtain a liquid mixture, or two solid compositions, preferably powders, are mixed (e.g. by dry blending) to obtain a dry mixture, preferably a . In case drying is performed prior to mixing, it is preferred that both UF retentates originating from (a-i) and (a-ii) are subjected to the drying of step (e-i) and (e-ii) prior to mixing, and the resulting solids are dry blended. Preferably, the dried compositions are powders. In an especially preferred ment, both streams are liquid during mixing and the drying of step (e-i) and (e-ii) is performed on the liquid mixture, after mixing of the UF retentate originating from step (a-i) and (a-ii).

In another preferred embodiment, the UP of step ) is performed on a mixture of the (ﬁrst) liquid animal skim milk composition and the (second) liquid animal whey composition of the present invention. Mixing of the ﬁrst liquid composition with the second liquid composition thus is performed prior to ultraﬁltration. This mixing of the ﬁrst liquid composition with the second liquid composition enables the tion of the protein composition of the ﬁrst liquid composition, in particular the alteration of the protein composition of animal skim milk. The (weight or ) ratio in which the second and the ﬁrst liquid composition are mixed is dependent on the exact protein composition of the incoming ﬁrst liquid composition but is mainly determined by the desired protein composition in the resulting UF ate, and preferably the resulting dry milk formula.

Both in case the ﬁrst liquid composition and the second liquid composition are subjected to ultraﬁltration of step (a-i) and (a-ii) separately, or UP is by step ), the UP retentates originating from step (a-i), (a-ii) and/or (a-iii) may undergo further processing steps, either prior to the mixing of the UP retentates originating from (a-i) and/or (a-ii) or the UP retentate originating from (a-iii). Such optional further processing steps include, and are preferably limited to, trating the liquid composition (i.e. increasing the protein/water weight ratio, e.g. via (partial) evaporation or ﬁltration techniques such as nanoﬁltration or reverse osmosis), heat-treatment (e.g. pasteurization (such as HTST, ESL or UHT) or sterilization (dry heat or moist heat)) and/or supplementation of additional water or other components. Preferably, the UP retentate originating from (a-i) and/or (a-ii) are subjected to a concentration step, prior to or after mixing of the UP ates in step (b), preferably using nanoﬁltration, optionally enhanced with ration, and/or reverse osmosis.

Performing the concentration step on the individual UF retentates has the advantage that more ﬂexibility and ﬁne-tuning is d in the process of the invention. Preferably, the UP retentate originating from ) or (b) is subjected to a concentration step, ably using nanoﬁltration, optionally enhanced with ration, and/or reverse osmosis. In an optional embodiment, the drying of step (e-i) or (e-ii) occurs on each of the UP retentates originating from UF of the ﬁrst and second liquid composition separately, prior to .

In an especially preferred embodiment, the further processing steps that may be performed on the UF retentates of (a-i) and (a-ii) prior to mixing thereof do not include any polyvalent ion removal step or any step that fractionates the proteins.

Mixing (such as in step (b)) Mixing of the ﬁrst liquid composition with the second liquid ition prior to (a-iii), or combining of the UF retentates originating from (a-i) and (a-ii) in step (b) may be accomplished by any means known in the art, such as “in pipe” (i.e. by the joining of two ng pipes into one single outgoing pipe), in a (balance) tank or vessel, in an agitated vessel or by any industrial mixer or blender. In case two liquid streams are mixed, dynamic mixing or static mixing may be employed. In case two dried streams (e. g. two powders) are mixed, a dry blender such as a ribbon blender, a paddle blender, a tumble blender and a vertical blender, may be employed. Preferably, the mixing step is performed on two liquid streams, preferably “in pipe” or in a balance tank. The ratio in which the ﬁrst animal skim milk composition is mixed with the second animal whey composition prior to (a-iii), or mixing of the UF retentate originating from (a-i) and (a-ii) in step (b) is conveniently inﬂuenced by controlling the ﬂow rate of the incoming compositions.

Polyvalenl ion removal (step (0)) Ultraflltration of the ﬁrst animal skim milk composition and the second animal whey composition in (a-i) and (a-ii), or of the mixture thereof (in step (a-iii)) affords at least one ultraflltration permeate (UFP) comprising (or enriched in) lactose. At least one of the UF permeates originating from step (a) is softened in step (c) to obtain at least one softened UF permeate, which is subsequently combined in step (d) with any of the ates of the ultraflltration of step (a). In step (c) of the process according to the ion, polyvalent ions are d from any of the UF permeates originating from step (a). In case ultraflltration is by step (a-i) and , two UF permeates are obtained. In case the ultraflltration is by step (a-iii) on the e of the first liquid composition and the second liquid composition, one UF permeate is obtained. Thus, at least one of the UF permeates originating from UF of the ﬁrst liquid composition and the UF permeate originating from UF of the second liquid composition is subjected to the polyvalent ion l of step (c), or the UF permeate originating from (a-iii) is subjected to the polyvalent ion removal of step (c).

In case two UF permeates are obtained in the lltration of step (a-i) and (a-ii), the UF permeates ating therefrom may be combined prior to step (c), or step (c) is performed on at least one of the UP permeates, 1'.e. on only one of the UP tes or on each of the UP permeates separately. In case two UF permeates are obtained from the ultraflltration of step (a-i) and (a-ii), both UF permeates ating therefrom are subjected to the polyvalent ion removal in step (c), preferably the UFPl and the UFP2 are combined prior to step (c) into a single UF permeate such that one UF permeate is softened in (c).

The polyvalent ion removal of step (c) enables the removal of (significant) amounts of polyvalent ions. Preferably at least 10 or 20 wt%, or preferably 50 wt%, more preferably at least 70 wt% or at least 80 wt%, most ably at least 90 wt% of the polyvalent ions are removed.. Thus, the softened UF permeate comprises at least 50 wt% less polyvalent ions, preferably at least 70 wt% less, more preferably at least 80 wt% less, most preferably at least 90 wt% less polyvalent ions, when compared to the incoming UF permeate originating from step (a).

Softening of at least one of the UP permeates originating from the UP of step (a-i) and/or (aii ) or (a-iii) is preferably accompanied with or followed by the l of monovalent ions.

Preferably, the monovalent ion removal step causes the removal of significant amounts of monovalent ions. Preferably, at least 10 or 20 wt% of the monovalent ions are removed, more ably at least 35 wt% or at least 50 wt%, most preferably at least 60 wt% of the lent ions are removed. Removal of monovalent ions (such as from the at least one UF permeate originating from step (c) and/or at least one or all of the UP retentates originating from step (a-i) and/or (a-ii) or (a-iii) or (b)) is especially preferred in case the dairy product ed by the process according to the invention is further processed into a nutritional product suitable for infant nutrition.

Polyvalent ion removal and optionally monovalent ion removal may be accomplished using any technique known in the art, such as electrodialysis, ion exchange, salt precipitation, lactose crystallization, membrane ﬁltration techniques such as nanofiltration, optionally enhanced with diaflltration, or combinations thereof The preferred polyvalent ion removal technique is ion exchange. In the context of the present invention, lent ion removal, optionally combined with monovalent ion removal, also es the crystallisation of lactose from a liquid UF permeate originating from step (a-i) and/or (a-ii) or (a-iii) and simultaneously keeping (signiﬁcant amounts of) the polyvalent ions and preferably (signiﬁcant amounts of) the monovalent ions in solution. The obtained crystalline lactose is regarded to be a softened UF permeate in the context of the present invention, as it originates from the UF of step (a) and has (signiﬁcant amounts of) the polyvalent ions removed.

The process of the invention generates at least one or two UF permeates (from (a-i) and (a- ii)), or from (a-iii). In case two UF permeates are obtained, they are preferably combined prior to being subjected to polyvalent ion removal (i.e. softening), which can be followed by monovalent ion removal. In a more costly embodiment, the two UFP permeates of (a-i) and (a-ii) are separately subjected to polyvalent ion removal and optionally monovalent ion removal, to obtain two softened UF permeates which uently can be combined. Each of the softened UF permeates may then be used in the ining of step (d), preferably the softened UF te originating from (a-i) and the softened UF permeate originating from (a-ii) are mixed prior to the combining of step (d) or they are aneously combined during step (d). Each of the UP permeates originating from the UP of step (a-i) and/or (a-ii) or ) may undergo further processing steps prior to being subjected to the polyvalent ion l of step (c). Such optional further processing steps include, preferably are limited to, concentrating the liquid stream (i.e. increasing the lactose/water weight ratio, e. g. via al) evaporation or ﬁltration techniques such as nanoﬁltration or reverse osmosis), heat- treatment (e.g. pasteurization (such as HTST, ESL or UHT) or sterilization (dry heat or moist heat)) and/or supplementation of additional water or other components. Concentration may also be accomplished during the softening in step (c) or during the optional lent ion removal, e. g. during nanoﬁltration, optionally enhanced with diaﬁltration.

It is preferred that removal of polyvalent ions of at least one (or ably all) of the UF permeates originating from step (a-i) and/or (a-ii) or (a-iii) is performed by ion ge.

Preferably, this step is followed by subjecting the at least one or all of the softened UF permeate to nanoﬁltration (NF) in order to trate it and also remove ﬁcant amounts of) monovalent ions rom. Using this sequence of steps, the softened UF permeate from which (signiﬁcant amounts) of monovalent ions are removed, is then combined with any of the UP retentates in step (d) or dried and combined in step (e-ii).

During ion exchange, the polyvalent ions (e.g. Mg2+, Ca2+, PO43') are replaced by monovalent ions (typically Na+, K+, Cl'), and during nanofiltration these monovalent ions permeate through the nanoflltration membrane such that separation of lactose and monovalent ions is effectuated. Preferably, nanoflltration is enhanced with diaflltration, i.e. at least once an additional volume of water is added to the NF retentate, and the diluted NF retentate is subjected to NF again. Conveniently, the NF permeate, comprising monovalent ions, may be used to regenerate the ion exchange column(s).

It is especially preferred that removal of polyvalent ions of at least one (or preferably all) of the UF permeates ating from step (a-i) and/or (a-ii) is performed by a combination of steps comprising ltration, salt precipitation and precipitate removal. Preferably, this combination of steps also comprises electrodialysis. More preferably, removal of polyvalent ions is performed in the following order: ltration, salt precipitation and precipitate removal. Preferably, the precipitate removal is followed by a further nanofiltration step (preferably enhanced with diaflltration) or by electrodialysis, most preferably it is followed by electrodialysis. The salt itation step is mainly aimed at removal of polyvalent ions, in particular phosphate ions, such as m ate and ium phosphate, and can be achieved by creating suitable conditions under which calcium ions precipitate from the lactose-enriched liquid. These conditions e addition of a strong base, such as sodium hydroxide, pH adjustment to a neutral pH, such as between 6 and 8, and increasing the temperature to between 70 and 90 oC, followed by decreasing the temperature to a between and 30 oC. Also calcium and magnesium levels will decrease under these precipitation conditions. Subsequently, the precipitates may be removed by any technique known in the art (e.g. tion, centrifugation). Especially suitable to remove the precipitates is an ultrafiltration step. It is preferred that the resulting polyvalent ion-depleted UF permeate(s) is/are r desalted in a further nanofiltration step and/or an odialysis step, most preferably in an odialysis step. Any type of electrodialysis as known in the art may be employed. The result is a lactose-enriched, softened UF permeate as ed to in step (c) that can be ed in step (d) with a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) to obtain a combined product.

Combining step (09 Any or all of the softened UF permeates originating from step (c) is/are combined in step (d) with any of the UF retentates originating from step (a-i) and/or (a-ii) or (a-iii) to obtain a combined product. Thus, (i) the ed UF permeate originating from (a-i) and/or (a-ii) (either separate or combined, preferably combined), or (ii) the softened UF permeate originating from (a-iii) is added to any of the UF ates originating from step (a-i) and/or (a-ii) or (a-iii). Thus, the at least one softened UF permeate originating from step (c) is ed with the UF retentate originating from (a-i) and/or (a-ii) or (a-iii) or step (b).

Each of the softened UF permeates comprises lactose. As the skilled person will appreciate, the amount of any of the softened UF permeates that is to be recombined with any of the UP retentates, may depend on the desired amount of lactose in the ﬁnal dairy product, the amount and purity of lactose in each of the softened UF tes originating from step (c) that is subjected to the combination of step (d), and the amount of residual lactose present in any of the UP ates originating from step (a). In a preferred embodiment, at least 70 wt%, preferably at least 80 wt%, more preferably at least 90 wt% or even at least 95 wt%, most preferably at least 98 wt% of the lactose that is obtained in the UF permeate(s) originating from step (a) is combined in step (c) with the UP retentates originating from step (a). The lactose t in a liquid ition can readily be determined by skilled person, e.g. enzymatically or by HPLC.

Each of the softened UF permeates and each of the UF retentates may undergo r processing steps prior to the combining of step (d). The UF retentate ating from (a-i) and/or (a-ii) or (a-iii) or step (b) may be subjected to further processing steps prior to subjecting it to the combining of step (d). Such further processing steps include, preferably are limited to, trating the liquid stream (i.e. increasing the protein/water weight ratio, e.g. via (partial) evaporation or ﬁltration techniques such as nanoflltration or reverse osmosis), heat-treatment, e.g. pasteurization (such as HTST, ESL or UHT) or sterilization (dry heat or moist heat)) and/or mentation of additional water or other components.

Preferably, the UF retentate originating from (a-i) and/or (a-ii) or (a-iii) or step (b) is subjected to a concentration step after the ultraflltration of step (a) and prior to the combining of step (d), preferably using nanoflltration, ally enhanced with diaflltration, and/or reverse osmosis.

In an especially preferred embodiment, the UF ate originating from (a-i) and/or (a-ii) or (a-iii) or step (b) is not subjected to any to polyvalent ion removal step after the ultraflltration of step (a). ably, the UF retentate originating from (a-i) and/or (a-ii) or (a-iii) or step (b) is not subjected to electrodialysis, ion exchange and salt itation. In an optional embodiment, the drying of step (e-i) or (e-ii) occurs prior to combining of step (d) and the drying of step (d). Prior to the combining of step (d), any of the softened UF tes may undergo further processing steps. Such optional further processing steps include, preferably are limited to, concentrating the liquid stream (i.e. increasing the lactose/water weight ratio, e.g. via (partial) ation or ﬁltration techniques such as nanofiltration or reverse osmosis), heat-treatment (e.g. pasteurization (such as HTST, ESL or UHT) or sterilization (dry heat or moist heat)) and/or supplementation of additional water or other ents. Concentration may also be accomplished during the softening of step (c) or during monovalent ion l, e. g. during nanoflltration, optionally enhanced with tration. In an optional embodiment, the drying of step (e-i) or (e-ii) occurs prior to ing of step (d).

Drying step (e-l) 0r (e-il) The s according to the invention involves a drying step (e-i) or (e-ii) that is performed on the one or more UF retentates originating from step (a-i) and/or (a-ii) or (a-iii) or step (b) and at least one of the softened UF permeates originating from step (c), or on the combined product originating from step (d), preferably the drying of step (e-i) is performed on the ed product originating from step (d). Drying may occur prior to the combining of step (d) and/or after the combining of step (d). In case drying occurs after combining, the combined product originating from step (d) is dried, preferably into a powder. In case drying occurs prior to combining, the one or more UF retentates originating from step (a) and at least one of the softened UF permeates originating from step (c) are dried separately, all preferably into a powder. Alternatively, drying may also occur prior to the combining of step (d) on one of the one or more UF retentates originating from step (a) and at least one of the softened UF permeates originating from step (c), preferably into a powder, and the dried composition, preferably in the form of a powder, is recombined with the remaining liquid composition. As such, an additional drying step is preferably performed to dry the combined product originating from step (d) in order to obtain a dry formula.

Drying may be accomplished by any means known in the art, e. g. spray drying, (ﬂuidized) bed drying, drum drying, freeze drying, roller drying, etc. In an especially preferred embodiment, drying is accomplished using spray drying, optionally preceded by partial evaporation of the liquid (e. g. by nanoflltration, reverse osmosis, evaporation).

In an especially preferred embodiment, the drying of step (e-i) occurs after the combining of step (d), as this order of steps requires the least amount of drying steps to obtain a dry formula, only one on the combined product originating from step (d). As such, the UP retentate originating from (a-i) and/or (a-ii) or (a-iii) or step (b), and the liquid softened UF permeate originating from step (c) is combined with the liquid mixture of UP ates in step (d), after which the combined product is dried in step (e-i), preferably spray-dried.

Herein, only one drying step is needed in the manufacture of dry formula, preferably an infant formula base . Normally, more drying steps are , such as drying of a casein containing composition or drying of skim milk, drying of a whey protein containing composition and drying of lactose. Drying, such as spray-drying, is a costly procedure, which is typically performed at high temperatures, such as above 150 0C or even above 180 oC. Reducing the amount of (spray-)drying to a single step greatly improves the efficiency of the process.

Drying step (e-ii) involves drying of any UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) which is not combined in step (d), and drying any of the softened UF tes originating from step (c) which is not ed in step (d), followed by ing the dried UF retentate with the dried softened UF permeate to obtain a dry milk formula. For instance, if the UF retentate originating from (b) is combined in step (d), it is subsequently dried in step (e-i), and not dried and combined in step (e-ii).

Where the drying of step (e-i) or (e-ii) occurs after the combining of step (d), the combined t may undergo further processing steps prior to the drying. Such optional further processing steps include, preferably are limited to, concentrating the liquid stream (zle. increasing the protein/water weight ratio, e.g. via (partial) ation or ion techniques such as nanofiltration or e osmosis), heat-treatment (e.g. pasteurization (such as HTST, ESL or UHT) or sterilization (dry heat or moist heat)) and/or supplementation of additional water or other components. In an especially preferred ment, the further processing steps that may be performed on the combined product prior to the drying of step (e-i) do not include any polyvalent ion removal step or any step that fractionates the proteins.

The drying of step (e-i) or (e-ii) obtains a dry formula, ably in the form of a powder. In the context of the present invention, a dry formula has a water content of at most 10 wt%, preferably 0 — 8 wt%, more preferably 2 — 4 wt%, based on total weight of the composition.

The dry formula may be further processed into nutritional products, preferably products le for feeding infants.

The process according to the invention yields a dry milk formula, ably in the form of a powder. In a preferred embodiment, this dry milk product is further processed into a nutritional product suitable for providing nutrition to a human infant, in particular an infant between 0 and 36 months of age. Further processing lly comprises on of further ingredients to the dairy product as known in the art, in ular one or more selected from vitamins, minerals, lipids, prebiotics, probiotics, lactose. Where appropriate, those ingredients may also be added to any of the UF retentates or UF tes originating from step (a), or (b) the softened UF permeate ating from step (c) and the combined product originating from step (d) prior to drying, or even to any of the incoming first and second liquid compositions. The skilled person is well aware of the ial and beneficial ingredients for infant ion, and how they are best blended with the protein fraction.

Further processing of the dry milk formula preferably comprises one or more of homogenization, heat-treatment, wet and/or dry blending of one of the above mentioned ingredients. ective of the combining of the lactose in any of the softened UF permeates originating from step (c) with any of the UF retentates originating from step (a) or (b), additional supplementation of lactose may be needed to fulfill the requirements for infant nutrition.

The process according to the invention provides sufficient removal of polyvalent ions and preferably monovalent ions, by virtue of the ultraflltration of step (a) and the polyvalent ion removal of step (c), so that all minerals are at or below their required level for infant nutrition. In case the t of a certain mineral is below the ed level, preferably that mineral is added to be on target (e.g. EU directive 91/321/EEC, or EU directive 2006/141/EC, US Food and Drug Administration 21 CFR Ch 1 part 107).

The s according to the invention affords residual water at several points, e. g. from the drying step and optionally as nanoflltration permeate, as reverse osmosis permeate. In a preferred embodiment, this residual water, optionally after further purification by e.g. reverse osmosis, is recycled in the process ing to the invention, e. g. used to dilute or reconstitute the ﬁrst liquid composition and/or the second liquid composition or as diaflltration water.

Intermediary products The process of the t invention generates several intermediary products: 1) the combined UF retentates originating from step (a-i) and (a-ii), 2) a combined product of the softened UF permeate and UP retentate of step (d), and 3) a dried combined product of step (e-i) or (e-ii) in case a dry infant milk formula is meant to be obtained.

Intermediaryproduct I) Intermediary product 1 is obtained by separately subjecting the UF retentates originating from (a-i) and (a-ii) to a nanoflltration step and combining the (protein comprising) fraction thereof (zle. the nanofiltration ate originating therefrom). The UF retentates are preferably combined in a weight or volume ratio of n 3:1 and 1:3.

Intermediary product 1 is characterized by (based on total dry weight of the composition): a protein content of between 40 and 52 wt%, wherein casein and whey are present in a weight ratio which lies between 70:30 and 30:70, lactose in an amount of between 35 and 50 wt%, and the presence of the following minerals: magnesium in an amount of between 0.01 and 0.30 wt%, calcium in an amount of n 0.80 and 1.70 wt%, orus in an amount of between 0.60 and 1.50 wt%, sodium in an amount of between 0.10 and 0.60 wt%, chloride in an amount of n 0.05 and 0.60 wt% and potassium in an amount of between 0.60 and 1.50 wt%. Preferably, this product comprises NPN in an amount of between 1.50 and 3.30 wt%, preferably between 1.90 and 3.0 and fat in an amount of between 2.0 and 3.50, preferably between 2.30 and 3.30 and ash in an amount of between 4.0 and 10.0 wt%.

Preferably, the intermediary product 1 is .

More preferably, intermediary product 1 is characterized by (based on total dry weight of the composition): a protein content of between 42 and 50 wt%, wherein casein and whey are present in a weight ratio which lies between 65:35 and 35:65, lactose in an amount of between 37 and 46 wt%, and the presence of the following minerals: magnesium in an amount of between 0.05 and 0.20 wt%, calcium in an amount of between 0.95 and 1.50 wt%, phosphorus in an amount of between 0.60 and 1.30 wt%, sodium in an amount of between 0.20 and 0.45 wt%, chloride in an amount of n 0.15 and 0.40 wt% and potassium in an amount ofbetween 0.70 and 1.20 wt%.

Intermediaryproduct 2) Intermediary product 2 is obtained by separately subjecting the UF retentates originating from (a-i) and (a-ii) to a concentration step (in this case nanof11tration), combining the concentrated in comprising) UF retentate (1'.e. the nanof11tration retentate originating therefrom) and ing the thus obtained liquid composition with the softened and concentrated UF permeate (1'.e. the UF permeates originating from (a-i) and (a-ii) were combined after UF, subjected to ion exchange and concentrated by nanof11tration).

Intermediary product 2 is terized by (based on total dry weight of the composition): a protein content of n 16 and 24 wt%, wherein casein and whey are present in a weight ratio which lies between 70:30 and 30:70, lactose in an amount of between 65 and 80 wt%, and the presence of the following minerals: ium in an amount of between 0.01 and 0.25 wt%, calcium in an amount of n 0.20 and 0.80 wt%, phosphorus in an amount of between 0.40 and 0.80 wt%, sodium in an amount of between 0.20 and 0.80 wt%, de in an amount of between 0.30 and 0.90 wt% and potassium in an amount of between 0.30 and 0.90 wt%. Preferably, this product comprises NPN in an amount of between 1.30 and 2.80 wt%, preferably between 1.50 and 2.60 and fat in an amount of between 0.5 and 2.0, preferably between 0.75 and 1.70 and ash in an amount of between 2.0 and 8.0 wt%. ably, the intermediary product 2 is liquid.

Intermediaryproduct 3) Intermediary product 3 is a dry milk formula for feeding a human infant with an age of between 0 - 36 months, such as a -on formula or infant formula, which is obtained by -)drying intermediary product 2 to which suitable amounts of additional nutrients are added to reach target levels thereof Said nutrients include dietary ﬁbers (in particular galacto-oligosaccharide and/or fructo-oligosaccharides), minerals (where ), lactose (where desired), vitamins, fats. The dry formula contains between 1.0 and 3.0 wt% moisture.

Fi re The Figure depicts preferred embodiments of the system according to the invention. With reference to the included Figure, the system according to the invention is bed as follows.

System The t invention also relates to an apparatus or system speciﬁcally designed to implement the process according to the invention. The system according to the invention is preferably a modular system, in which at least three, preferably at least four modules are in ﬂuid connection with each other, with the option that the ﬂuid connection(s) can be closed off when and where necessary. Herein, each module may be a separate unit or two or more modules may be integrated as a single unit. Preferably, each module is a separate unit and is distinguishable as such in the system.

The system ing to the invention is arranged to receive two incoming liquid compositions (1'.e. the animal skim milk composition and the animal whey composition as deﬁned herein) and to discharge one solid composition (e. g. a dry milk formula). In on thereto, further liquid and/or solid compositions may be received by the system or discharged from the system.

The system according to the invention comprises an ultraﬁltration module (1), comprising an ultraﬁltration membrane (lb). The ﬁrst module is designed to receive the ﬁrst liquid composition (1'.e. the animal skim milk composition as deﬁned herein), or a e of the ﬁrst and second liquid itions, via a ﬁrst inlet (la) to a ﬁrst side of the UP membrane (lb). In on, the ultraﬁltration module (1) comprises a ﬁrst outlet (lc) for discharging WO 63493 an ultraﬁltration retentate (UFR) from the ﬁrst side of the UP membrane (lb) and a second outlet (ld) for discharging an ultraﬁltration permeate (UFP) from the second side of the UP ne (lb).

The UF membrane has two sides, one for ing the ﬁrst liquid composition, or a mixture of the ﬁrst and second liquid compositions, and discharging the UFR, and one for discharging the UFP. The retentate is discharged from the same side of the UF membrane (lb) as the ﬁrst liquid composition, or a mixture of the ﬁrst and second liquid compositions, is ed, and the UF permeate is discharged from the other side of the UF ne. The UFP thus comprises only material that has permeated through the UF membrane (lb). The UF membrane (lb) employed in the ltration module (1) can be any UF membrane known in the art, including ceramic membranes and organic spiral wound membranes, preferably UF membrane (lb) is an organic spiral wound membrane. UF membrane (lb) has a molecular weight cut-off that s proteins, such as whey proteins and casein, to remain in the retentate. Preferably, the molecular weight cut-off is at most 25 kDa, more preferably at most 10 kDa, and preferably of at least 2.5 kDa, more preferably at least 5 kDa.

Optionally, the system according to the invention comprises a second ultraﬁltration module (10), comprising a second ultraﬁltration membrane (10b). The second ultraﬁltration module 2O (10) is ed to receive the second liquid composition (i.e. the animal whey composition as deﬁned herein) via a ﬁrst inlet (10a) to a ﬁrst side of the second UF membrane (lOb). In addition, the second ultraﬁltration module (10) comprises a ﬁrst outlet (lOc) for discharging a second ultraﬁltration retentate (UFR) from the ﬁrst side of the second UF membrane (10b) and a second outlet (lOd) for discharging a second ultraﬁltration permeate (UFP) from the second side of the second UF membrane (10b). The second UF ne (lOb) employed in the ultraﬁltration module (10) can be any UF membrane known in the art, including ceramic membranes and organic spiral wound membranes, preferably UF membrane (10b) is an organic spiral wound membrane. UF membrane (lOb) has a molecular weight cut-off that enables proteins, such as whey proteins and , to remain in the retentate.

Preferably, the lar weight cut-off is at most 25 kDa, more preferably at most 10 kDa, and preferably of at least 2.5 kDa, more preferably at least 5 kDa.

The system according to the invention comprises a polyvalent ion removal module (2) for removing polyvalent ions from one or more ltration permeates (UFPs) originating from ultraﬁltration module (1) and optionally from ultraﬁltration module (10). The polyvalent ion l module (2) comprises an inlet (2a) for receiving the one or more UFPs, means for ng polyvalent ions from the UFP (2b), and an outlet (2c) for discharging a softened UFP. The polyvalent ion removal module (2) removes (signiﬁcant amounts of) polyvalent ions (i.e. ions having a positive or negative charge of two or more) from the UFP, and may also remove (signiﬁcant amounts of) monovalent ions from the UFP. Preferably, the polyvalent ion removal module (2) comprises means for ng (signiﬁcant amounts of) polyvalent ions and means for removing (signiﬁcant amounts of) monovalent ions. In case means for removing (signiﬁcant amounts of) polyvalent ions and means for removing (signiﬁcant amounts of) monovalent ions are both t, those means may be a single means, capable of ng both polyvalent and monovalent ions, or preferably two separate means, one capable of removing polyvalent ions (2b) and one capable of removing monovalent ions (2f). The two te means for removing ions may be present in two ct units within module (2), wherein an outlet (2d) of the ﬁrst unit (2b), preferably for removing polyvalent ions, is in ﬂuid connection with an inlet (2e) of the second unit (2f), preferably for removing monovalent ions, and outlet (2c) is arranged for discharging a softened UFP from the second unit (2f).

Any technique known in the art for removing polyvalent and optionally monovalent ions may be used as means for removing polyvalent ions (2b) and optionally means for removing monovalent ions (2f). iently, the ion removal unit(s) is/are ed from an electrodialysis set-up (comprising ion ge membranes and means for applying an electric potential difference over said ion exchange membranes), an ion exchange set-up (comprising at least one column ﬁlled with anionic and/or cationic resins), a salt precipitation set-up, a nanoﬁltration membrane, optionally with an onal inlet for receiving diaﬁltration water, or combinations thereof In a preferred embodiment, module (2) comprises at least one ion exchange column sing anion and/or cation exchange resins as polyvalent ion removal unit (2b) and a nanoﬁltration membrane as monovalent ion removal unit (2f). In an especially preferred embodiment, module (2) comprises at least one nanoﬁltration membrane, a salt precipitation set-up and a means for precipitation removal (preferably an ultraﬁltration membrane), more preferably module (2) further comprises an electrodialysis set-up. Most preferably, module (2) comprises, in the following serially placed order, at least one nanofiltration membrane, a salt precipitation set-up, a means for precipitation removal rably an ultraflltration membrane) and an electrodialysis set-up.

In the system according to the invention, the polyvalent ion removal module (2) is arranged in between the ultraflltration (s) (l and optionally 10) and the mixing module (3).

The system ing to the invention comprises a mixing module (3) for mixing at least two liquid streams, at least two solid streams (e. g. s) or at least one liquid stream and at least one solid stream, preferably for mixing at least two liquid streams. The mixing module (3) preferably enables mixing of the UP retentate originating from ultraf11tration module (1), the UF retentate originating from ultraflltration module (10) and the softened UF permeate ating from polyvalent ion removal module (2).

In a ﬁrst preferred embodiment, the mixing module (3) is designed to mix the UF retentate originating from ultraf11tration module (1), the UF retentate ating from ultraflltration module (10) and the softened UF permeate originating from polyvalent ion l module (2). Thus, in the ﬁrst preferred embodiment the mixing module (3) is designed to receive a softened UF permeate ating from polyvalent ion removal module (2) (either as liquid 2O or solid) via a first inlet (3a), the UF retentate ating from ultraflltration module (1) (either as liquid or solid) via a second inlet (3b) and the UF retentate originating from ultraflltration module (10) (either as liquid or solid) via a third inlet (3d). The mixing module (3) further comprises an outlet (3c) for rging a recombined product (either as liquid or solid).

In a second preferred embodiment, two mixing modules exist, one mixing module (30) for mixing the ﬁrst liquid composition with the second liquid composition and for discharging a mixture of the first and second liquid compositions, and one mixing module (3) for mixing the mixture of the UF retentate originating from ultraflltration module (1) and the UP retentate originating from ultraflltration module (lO)with the softened UF permeate originating from polyvalent ion removal module (2). In the second preferred ment the ﬁrst mixing module (30) is designed to receive the first liquid composition via a first inlet (30a) and the second liquid composition via a second inlet (30b), and to discharge the mixture of the ﬁrst and second liquid compositions via an outlet (3 0c). Thus, the ﬁrst mixing module (30) comprises a ﬁrst inlet (30a) and a second inlet (30b) for ing liquid compositions and an outlet (30c) for discharging a mixed liquid composition. The second mixing module (3) is designed to receive the softened UF permeate originating from polyvalent ion removal module (2) (either as liquid or solid) via a ﬁrst inlet (3a) and the mixture of the UF retentate originating from ultraﬁltration module (1) and the UF retentate originating from ultraﬁltration module (10) r as liquid or solid) via a second inlet (3b), and to discharge the ined product via an outlet (3 c). Thus, the second mixing module (3) comprises a ﬁrst inlet (3a) and a second inlet (3b) for receiving liquid and/or solid compositions and an outlet (3c) for discharging a recombined liquid or solid composition.

In the mixing module(s) according to the invention, mixing may be accomplished by any method known in the art. Mixing may be accomplished by merely combining two or more itions. The mixing module(s) may further comprises mixing means. The mixing means may be any means suitable for mixing two compositions known in the art, such as “in pipe” (zle. by the joining of two or more incoming pipes into one single outgoing pipe), in a (balance) tank or vessel, in an agitated vessel, or by any industrial mixer or blender known in the art. Suitable mixing means include means for mixing two liquid compositions, e.g. dynamic mixing or static mixing, or for mixing two solid itions (e. g. two powders), e. g. a dry blender such as a ribbon blender, a paddle r, a tumble blender and a vertical r, or one liquid composition and one solid ition, preferably for mixing two liquid compositions. In an especially preferred embodiment, the mixing means is “in pipe” or in a balance tank.

Mixing module (3) and optional mixing module (30) may be arranged in the system before the ultraﬁltration module (1) or after the ultraﬁltration module (1). In case the mixing module (3 O) is arranged before the ultraﬁltration module (1), the ﬁrst liquid composition and the second liquid composition are mixed prior to ultraﬁltration. In case the mixing module (3) is arranged after the ultraﬁltration modules (1) and (10), the ﬁrst and second liquid compositions are each ultraﬁltered separately prior to mixing of the UF ates originating from ultraﬁltration modules (1) and (10).

The system according to the invention ably comprises a drying module (4), which is arranged for drying at least one liquid composition. The drying module (4) is designed to e a liquid composition (e.g. the recombined product) via an inlet (4a) to a drying means (4b), and to discharge a solid composition via an outlet (4c) from the drying means (4b). The drying means (4b) may be any means suitable for drying a liquid composition known in the art, e. g. a spray dryer, a (ﬂuidized) bed dryer, a drum dryer, a freeze dryer, a roller dryer, etc. In an especially preferred embodiment, the drying means (4b) is a spray dryer.

The drying module (4) may be arranged in the system before the mixing module (3) or after the mixing module (3), as long as it is arranged after the ultraﬁltration module (1) and optional ultraﬁltration module (10). In case the drying module (4) is arranged in between the ultraﬁltration module (1) and optional ultraﬁltration module (10) and the mixing module (3), at least one of the ultraﬁltration retentates originating from ultraﬁltration modules (1) and optionally (10) is dried prior to mixing. In case the drying module (4) is arranged after the mixing module (3), the ultraﬁltration retentates are ﬁrst mixed and then the mixture of the UF ate originating from ultraﬁltration module (1) and the UF retentate originating from ultraﬁltration module (10) is dried.

Optionally, the system ing to the ion comprises r drying module(s), each for drying at least one liquid stream. Each drying module is designed to e a liquid composition via an inlet to a drying means, and to discharge a solid composition via an outlet from the drying means. The drying means may be any means suitable for drying a liquid composition known in the art, e. g. a spray dryer, a (ﬂuidized) bed dryer, a drum dryer, a freeze dryer, a roller dryer, etc. In an especially red embodiment, the drying means is a spray dryer. A further drying module may be arranged in the system before the mixing module (3) and after the second ultraﬁltration module (10), preferably in case the ﬁrst drying module (4) is arranged before the mixing module (3) and after the ﬁrst ultraﬁltration module (1). As such, the ultraﬁltration retentates discharged from both ultraﬁltration modules (1) and (10) are dried prior to mixing in the mixing module (3).

In a ﬁrst preferred embodiment, the system according to the invention comprises two ultraﬁltration modules (1) and (10). Outlet (lc) of the ﬁrst ultraﬁltration module (1) is in WO 63493 ﬂuid connectivity with inlet (3b) of the mixing module (3), and outlet (ld) is in ﬂuid connectivity with inlet (2a) of the polyvalent ion removal module (2). Outlet (lOc) of the second ltration module (10) is in ﬂuid connectivity with inlet (3d) of the mixing module (3), and outlet (lOd) is in ﬂuid tivity with inlet (2a) of the polyvalent ion removal module (2). Outlet (2c) is in ﬂuid connectivity with inlet (3 a) of the mixing module (3), and outlet (3c) is in ﬂuid connectivity with inlet (4a) of the drying module (4). Inlets (la) and (10a) are arranged to e liquid compositions to the system (e.g. animal skim milk and animal whey) and outlet (4c) is arranged to discharge a solid composition from the system (e.g. a dry milk formula). Especially preferred is that module (2) comprises a polyvalent ion removal unit (2b), preferably at least one ion exchange , and a monovalent ion removal unit (2f), preferably a nanoﬂltration ne.

In a second preferred embodiment, the system according to the invention comprises two mixing modules (3) and (30). Outlet (30c) of the ﬁrst mixing module (30) is in ﬂuid connectivity with inlet (la) of the ultraﬂltration module (1). Outlet (lc) is in ﬂuid connectivity with inlet (3b) of the second mixing module (3), and outlet (ld) is in ﬂuid connectivity with inlet (2a) of the polyvalent ion removal module (2). Outlet (2c) is in ﬂuid connectivity with inlet (3a) of the second mixing module (3), and outlet (3c) is in ﬂuid connectivity with inlet (4a) of the drying module (4). Inlets (30a) and (30b) are arranged to 2O e liquid compositions to the system (e.g. animal skim milk and animal whey) and outlet (4c) is arranged to discharge a solid composition from the system (e.g. a dry milk formula). Especially preferred is that module (2) comprises a polyvalent ion removal unit (2b), preferably at least one ion exchange column, and a monovalent ion removal unit (2f), preferably a nanoﬂltration membrane.

The system according to the invention may comprise further s or further features as described here below.

In a further preferred embodiment, the system according to the invention comprises one or more concentration module(s) for concentrating (a) liquid stream(s). Such a concentration module comprises an inlet for receiving a liquid ition to a means for concentrating, a means for concentrating and an outlet for discharging a concentrated liquid composition.

Any concentration technique known in the art may be used as means for concentrating.

WO 63493 Conveniently, the means for concentrating is selected from an evaporation set-up (e.g. by increasing the temperature and/or ng the pressure) or a membrane ﬁltration set-up (e.g. a reverse osmosis membrane or a nanoﬁltration membrane). A concentration module may also be combined with the polyvalent ion removal module (2), as such accomplishing concentration during monovalent ion removal (e. g. using nanoﬁltration optionally enhanced with diaﬁltration).

In a further preferred embodiment, the system according to the invention comprises means for recycling ual) water from outgoing streams to incoming streams. al water may be obtained in the drying module (4), in the polyvalent ion removal module (2) (e. g. as nanoﬁltration permeate) and in each of the concentration modules (e. g. as reverse osmosis permeate). Preferably, at least one of the drying module (4), the polyvalent ion l module (2) and a concentration module further comprises an additional outlet for discharging water from the module, more preferably at least one of the tration modules comprises such an additional outlet. Most preferably, the drying module (4), the polyvalent ion removal module (2) and each of the tration modules each comprise such an outlet. The residual water may be used to dilute any of the incoming liquid compositions, e. g. the ﬁrst liquid ition and/or the second liquid composition, or may be used as diaﬁltration water, e. g. in the polyvalent ion removal module (2). Preferably, the 2O ﬁrst ltration module (1) and/or the second ultraﬁltration module (10) module and/or the polyvalent ion removal module (2) further comprise an additional inlet for receiving residual water. The skilled person appreciates that the outlets for discharging residual water are in ﬂuid connectivity with the inlets for receiving residual water, preferably by means of a conduit, wherein optionally one or more collection tanks or one or more further puriﬁcation means (e.g. reverse osmosis membranes) are integrated.

In a further preferred embodiment, the system according to the ion comprises means for heat-treating a liquid composition. Any of the liquid compositions which are led through the system according to the invention may suitably be heat-treated, using any heat-treatment technique known in the art. iently, the system according to the invention comprises at least one heat-treating , arranged for heat-treating a liquid composition. Such a heat-treatment module comprises an inlet for ing a liquid composition to a means for heat-treatment, a means for heat-treatment and an outlet for discharging a heat-treated liquid ition. Any heat-treatment technique known in the art may be used as means for heat- treatment, such as pasteurization or sterilization set-up. Preferably, a plate xchanger (PHE) and/or a direct steam injection/infusion (D81) is used as heat-treatment means.

The system ing to the invention may further comprise chilling means, preferably to enable the system to operate at a temperature below 15 0C, more ably below 12 oC.

The skilled person will understand that freezing of the liquid stream is highly undesirable, at that the temperature should be kept high enough for the different liquid streams to remain . Typically, the chilling means enable the system to operate at a temperature of at least 2 oC. Each module may have a separate chilling means, or a central chilling means may be installed to regulate the temperature in the entire system. Preferably, the chilling means are selected from cooling tower, heat-exchanger (plate or tubular, preferably in connection with the PHE used for reatment), cooling by coolant (heat-transfer ﬂuid), pumpable ice technique.

In case a module comprise a nanofiltration membrane, the nanofiltration may optionally be enhanced by diaflltration. To accomplish diaflltration, the module requires an additional inlet for receiving water to the first side of the nanofiltration membrane, as such enabling dilution and re-flltration of the nanofiltration retentate. In a preferred embodiment, the 2O polyvalent ion removal module (2) comprises such an additional inlet (2d).

All ﬁltration modules preferably comprise means to tate the permeations of the solvent and optionally small solutes through the membrane. Any means known in the art may be used to accomplish easy permeation, such as using gravity or the application of transmembrane re (TMP). TMP may be lished by pressurizing the first side of the membrane (i.e. the retentate side) or by depressurizing the second side of the membrane (i.e. the permeate side). Suitably, a pump using hydrostatic pressure to pressurize the ﬁrst side of the membrane and/or a pump generating suction at the second side of the membrane is used. Suitable pumps include centrifugal pumps and positive displacement pumps, preferably fugal pumps are used.

In the system according to the invention, the ent modules are interconnected, 1'.e. the outlet of one module is in ﬂuid connectivity with the inlet of another , preferably by WO 63493 means of a conduit. The different modules of the system, especially the ultraflltration module (1), the mixing module (3) and the drying module (4), may be interconnected in different conﬁgurations, as long as the system is arranged to implement the process according to the invention.

The system according to the invention preferably operates with 500 — 2500 kg, more preferably 800 — 1800 kg, most preferably 1000 — 1400 kg dry matter of the first liquid composition, preferably of animal skim milk, incoming per hour. The system according to the invention preferably es with 1500 — 5000 kg, more preferably 2200 — 4000 kg, most preferably 2600 — 3000 kg dry matter of the second liquid composition, preferably of animal whey, incoming per hour. The system according to the invention preferably es with 750 — 4000 kg, more preferably 1000 — 3000 kg, most ably 1500 — 2000 kg UF retentate discharged from the ultraflltration module(s) per hour from both incoming streams combined. The process according to the invention preferably operates with 1000 — 5000 kg, more preferably 1500 — 4000 kg, most preferably 2000 — 2500 kg UF permeate discharged from the ultraflltration module(s) per hour from both incoming streams ed.

The invention will now be illustrated by several es which are not meant to limit the invention in any manner.

Example I 400 kg of pasteurized cows’ skim milk with a casein to whey protein weight ratio of 80:20 was subjected to ultraflltration over a Synder ST3 838 UF ne having a MWCO of 10 kDa. Ultraflltration was performed at a temperature between 8 and 10 0C, with a transmembrane pressure of 2 bar and a VCF of about 2. The permeate was ted in a ﬂow rate of up to 260 L/h. 208 kg of a UF permeate (UFPl) and 211 kg of a UF retentate (UFRl) was obtained. The compositions of the incoming skim milk and the products of the ultraflltration are given in table 1. The slight increase in total weight of the ﬁnal products (UFRl and UFPl) compared to the incoming skim milk can be attributed to dilution of the plant dead volume during the changeover from product to water during plant ﬂushing. As can be seen from the data of table 1, the UF retentate is enriched in proteins, s the UF permeate is ed in lactose.

Table I .' itions ofexample I (in wi% based on total dry weight) Component Cows’ skim milk UFRl UFPl protein 36.2 51.7 0.0 Lactose 51.8 36.5 87.6 ash 8.7 8.4 9.1 - Na 0.46 0.35 0.70 - K 1.83 1.40 2.69 - Cl 1.13 0.66 1.61 - P 1.16 1.32 0.76 - Ca 1.37 1.67 0.80 - Mg 0.12 0.12 0.13 Example 2 1000 kg of pasteurized sweet whey with whey proteins as the sole protein source was subjected to ultraﬁltration over a Synder ST3838 UF membrane having a MWCO of 10 kDa. Ultraﬁltration was performed at a temperature between 10 and 12 0C, and with a transmembrane pressure of 2 bar and a VCF of about 5. The permeate was ted in a ﬂow rate of up to 400 L/h. 818 kg of a UF permeate (UFP2) and 195 kg of a UF retentate (UFR2) was obtained. The compositions of the incoming sweet whey and the products of the ultraﬁltration are given in table 2. The slight increase in total weight of the ﬁnal products (UFRl and UFPl) compared to the incoming sweet whey can be attributed to dilution of the plant dead volume during the changeover from product to water during plant ﬂushing.

Table 2.‘ Compositions ple 2 (in wi% based on total dry ) Component Sweet whey UFR2 UFP2 Protein 9.7 35.1 0.0 lactose 76.9 50.0 87.4 ash 8.6 6.7 9.3 - Na 0.67 0.49 0.74 - K 2.58 1.92 2.84 - Cl 1.44 0.95 1.69 - P 0.82 0.58 0.73 - Ca 0.81 0.69 0.86 -Mg 0.14 0.10 0.15 Example 3 The UFPl of example 1 and the UFP2 of example 2 were combined in a weight ratio of /80 to obtain 799 kg of a combined UFP. The combined UFP was subjected to ion exchange to produce a softened UFP, and subsequently to nanof11tration ed with diaf11tration. Ion exchange employed an anionic resin charged with chloride ions and a cationic resin charged with sodium ions, to exchange the polyvalent ions for sodium and chloride. Ion exchange operated at a pH between 2.4 and 4.3 and a temperature between 5 and 10 oC. Nanoflltration employed a Synder NFX 3838 NF membrane having MWCO of 150 — 300 Da, operated at a temperature between 8 and 22 0C, and with a transmembrane pressure of 2 bar. The permeate was collected in a ﬂow rate of up to 400 L/h. Two diaflltration volumes of, 200 L of water were added sequentially when the retentate total solids content reached 20%. The softened UFP was concentrated to a ﬁnal total solid t of about 20 %. 178 kg of a softened UFP concentrate was obtained as a 1tration retentate , er with 1225 kg of a nanof11tration permeate (NFPl). The compositions of the incoming combined UFP and the products of the nanof11tration are given in table 3. The great majority of the polyvalent ions were removed during ion exchange and the great majority of the monovalent ions ended up in the NFPl. The softened UFP concentrate (NFRl) ned almost exclusively lactose. 2014/050202 Table 3 .' itions ofexample 3 (in wi% based on total dry weight) component Combined UFP NFRl softened UFP concentrate (NFP1) protein 0.0 0.0 0.0 lactose 86.8 97.2 11.2 ash 9.2 2.4 74.7 -Na 0.71 0.61 24.7 - K 2.66 0.32 9.8 - Cl 1.70 0.84 44.9 - P 0.75 0.23 0.34 - Ca 0.84 0.06 0.36 - Mg 014 0.00 0.00 Example 4 The UFR1 of example 1 was concentrated and subjected to monovalent ion removal by nanoﬁltration over a Synder NFX 3838 NF ne having MWCO of 150 — 300 Da.

Nanoﬁltration operated at a temperature between 8 and 20 0C, and with a transmembrane pressure of 2 bar and VCF of about 2. The permeate was collected in a ﬂow rate of up to 220 L/h. 108 kg of an UFR1 concentrate as tration retentate (NFR2) was obtained, together with 149 kg of a nanoﬁltration permeate (NFP2). Using nanoﬁltration, the UFR1 is concentrated to a total solid content of about 18 %. The composition of the NFR2 product of the nanoﬁltration is given in table 4.

Table 4: Composition ofexample 4 (in wt% based on total dry weight) component NFR2 protein 55.6 lactose 33.4 ash 7.8 - Na 0.26 - K 1.06 - Cl 0.27 - P 1.33 - Ca 1.70 - Mg 0.12 Example 5 The UFR2 of e 2 was concentrated and subjected to monovalent ion removal by nanoﬁltration over a Synder NFX 3838 NF membrane having MWCO of 150 — 300 Da.

Nanoﬁltration operated at a temperature between 8 and 20 0C, and with a transmembrane pressure of 2 bar. The te was collected in a ﬂow rate of up to 400 L/h. 73 kg of an UFR2 concentrate as nanoﬁltration retentate (NFR3) was obtained, together with 148 kg of a nanoﬁltration permeate (NFP3). Using tration, the UFR2 is trated to a total solid content of about 18 %. The composition of the NFR3 product of the nanoﬁltration is given in table 5.

Table 5 .' Composition ofexample 5 (in wt% based on total dry weight) component NFR3 protein 35.8 lactose 51.0 ash 5.6 - Na 0.35 - K 0.82 - Cl 0.26 _ P 0.64 - Ca 0.66 - Mg 0.11 Example 6 The aim is to produce a mixture with a caseinzwhey ratio of 40:60. To this end, the UFRl concentrate of example 4 (NFR2) is mixed with the UFR2 concentrate of e 5 (NFR3) in a weight ratio of 59 kg:87.62 kg (based on a liquid composition) or in a weight ratio of .59 kg: 16.45 kg (based on a dry composition) tively, to produce a mixture of UFRl and UFR2. Besides the in table 6 mentioned constituents, the NFR2/NFR3 e comprises NPN at 2.82 wt% and fat at 3.08 wt%.

Table 6: Composition ofexample 6 (in wt% based on total dry weight) component NFR2/NFR3 mixture protein 43.6 lactose 44.1 ash 6.5 - Na 0.32 - K 0.91 - Cl 0.27 - P 0.91 - Ca 1.07 - Mg 0.12 Combining the UFRl concentrate of example 4 (NFR2) with the UFR2 concentrate of example 5 (NFR3) in another selected weight ratio allows to obtain a mixture which comprises casein to whey proteins in a desired ratio that falls within the claimed range.

Addition of a softened and optionally trated UF permeate (which is substantially free from proteins) allows one to increase the amount of e to a desired level. The obtained mixture can be spray-dried into a dry milk formula. For ce, addition of suitable s of required nutrients and minerals, where needed, allows one to obtain a growing- up formula with a 40:60 casein to whey protein ratio. Alternative mixtures of UFRl and UFR2 where made to produce other mixtures of UFRl and UFR2 that comprised a 50:50 and 60:40 casein to whey ratio.

Example 7 A ed UFP concentrate was recombined with the mixture of UFRl and UFR2 to produce a ition with a 60:40 casein to whey n ratio. The softened UFP concentrate was combined with the mixture of UFRl and UFR2. The UFRl concentrate of example 4 (NFRZ), the UFR2 concentrate of example 5 (NFR3) and the ed UFP concentrate (NFRl) of example 3 are mixed in a weight ratio of 88.51 81 kg:188.77 kg (based on a liquid composition) or in a weight ratio of 15.88 kg:8.23 kg:38.57 kg (based on a dry composition) respectively, to produce a mixture of UFRl, UFR2 and softened UFP.

Besides the in table 7 mentioned constituents, the NFRl/NFRZ/NFR3 mixture comprises NPN at 1.67 wt% and fat at 1.01 wt%.

Table 7.‘ Composition ofexample 7 (in wt% based on total dry weight) Component NFRl/NFRZ/NFR3 mixture Protein 18.8 Lactose 74.9 Ash 4.2 - Na 0.49 - K 0.58 - Cl 0.62 - P 0.56 - Ca 0.55 - Mg 0.05 Combining the softened UFP concentrate with the mixture of UFRl and UFR2 in other selected weight ratios allows obtaining a mixture which comprises casein to whey proteins in a desired ratio that falls within the claimed range. The addition of the softened and optionally concentrated UF permeate (which is substantially free from proteins) allows to increase the amount of lactose to a higher levels as shown. The obtained mixture can be spray-dried into a dry milk formula. For instance, addition of suitable amounts of required nts and minerals, where needed, allows one to obtain a growing-up formula with a 60:40 casein to whey protein ratio. ative mixtures where made in a r fashion to obtain compositions that comprised a 50:50 and 40:60 casein to whey ratio.

Example 8 onation of reconstituted skim milk powder (SMP) and reconstituted sweet whey powder (SWP) according to the invention was performed using a combination of unit operations, to prepare three types of infant nutrition base products. tituted SMP and reconstituted SWP were each subjected to UF (step 1), the retentates (UFRs) were subjected to NF (step 2) and the permeates (UFPs) to poly- and monovalent ion removal (step 3).

Subsequently, the NF retentates (NFRs) from step 2 and the softened UFPs from step 3 are combined in step 4. The compositions of SMP and SWP are given in table 8. Each step of the process operated in steady state conditions for 4 — 10 h, during which an acceptable average ﬂux was achieved throughout the entire production sequence. Concentration factors for the membrane ﬁltration steps are given in “mass concentration factor” (MCF), which are calculated in the same way as a VCF, but using weight d of volume. It can be assumed that MCF = VCF, since all densities are close to that of water (1000 kg/m3) and all solids present in the ng stream end up in the retentate and permeate streams. Over time, slight variations were observed for the MCFs. Here below, the MCF range is given or the deviation from the given value was less than 10 % at all times.

Table 8: Compositions ofSMP and SWP (per 100 gpowder) Component SMP SWP Protein (g) 35.2 13.5 Lactose (g) 53.3 76.6 ash (g) 7.83 8.38 - Na (mg) 397 666 - K (mg) 1690 3040 - Cl (mg) 979 1500 - P (mg) 1130 722 - Ca (mg) 1260 614 - Mg (mg) 106 130 -Zn (mg) 4.8 0.17 Step 1: Fractionation of tituted SMP and tituted SWP was performed using two 3838 10 kDa ultraf11tration membranes in series (Synder Filtration), to separate the feed materials into a n enriched retentate and a lactose/milk salts enriched permeate at 10 °C . The tituted skim milk feed material (~2800 kg) at a total solids t of 8.64 % w/w solid, pH of 6.9 at 5.8 °C, was fractionated using a mass concentration factor of 2, while the reconstituted sweet whey feed material (~3 500 kg) at a total solids content of 6.1 % w/w solid, pH of 6.63 at 6.8 °C was fractionated using a mass concentration factor of 5.5 The utritional and mineral distribution of the liquid retentate and permeate streams from UF1 and UF2 are presented in table 9. The permeates were collected with an average ﬂux of 10.54 kg/mZ/h (for SM) and 20.21 kg/mZ/h (for SW).

Table 9: itions of UFRS and UFPS (per 100 g) Component UFRl (SM) UFPl (SM) UFR2 (SW) UFP2 (SW) Total solids (g) 11.57 5.29 9.00 5.32 Protein (g) 6.36 0.14 3.47 0.16 Lactose (g) 4.14 4.68 4.57 4.71 ash (g) 0.97 0.48 0.66 0.44 - Na (mg) 38.5 34.0 38.2 32.6 -K(mg) 162.4 142.3 117.9 99.8 — Cl (mg) 79.1 91.7 91.7 107.9 — P (mg) 142.3 37.5 77.9 30.4 — Ca (mg) 190.5 32.8 79.1 19.2 — Mg (mg) 13.7 6.0 10.0 6.1 — Mn (mg) 0.004 0.00 0.001 0.00 — Fe (mg) 0.042 0.10 0.051 0.072 - Cu (mg) 0.014 0.07 0.033 0.010 -Zn (mg) 0.80 0.16 0.032 0.010 M: Post ultrafiltration of the reconstituted skim milk and sweet whey powder streams, the subsequent retentates UFRl and UFR2 were concentrated and partially demineralised using a 3838 150-300 Da nanofiltration (NF) membrane (GEA Filtration, Denmark). For concentration and demineralisation of ~ 500 kg of UFRl (pH 6.82 at 6 °C) to 26 % w/w solids content, NF1 used two NF membranes in series, while for concentration and demineralisation of ~ 640 kg UFR2 (pH 5.88 at 6.5 °C) to 28 % w/w solids content a single NF membrane was used in NF2. NF1 operated within a mass concentration factor range of 1.8 — 2.2 while NF2 operated within a mass concentration factor range of 2.6 — 3. Both NF1 and NF2 were operated within the temperature range of 13-14 °C. The permeates were collected with an average ﬂux of 1.64 kg/mZ/h (for UFRl) and 9.64 kg/mZ/h (for UFR2).

The macronutritional and mineral distribution of the liquid retentate and te s from NFl and NF2 are presented in table 10. The process yielded for NFRl and NFR2 milk protein concentrate (MPC50) and whey protein concentrate (WPC3 5) powders respectively.

Table 10: Compositions ofNFRS andNFPS (per 100 g) Component NFRl (SM) NFPl (SM) NFR2 (SW) NFP2 (SW) Total solids (g) 24.30 0.36 24.63 0.35 Protein (g) 12.8 0.08 9.45 0.08 Lactose (g) 9.67 0.05 13.65 0.05 ash (g) 1.66 0.23 1.29 0.28 - Na (mg) 51.2 23.6 51.7 52.7 - K (mg) 222.8 92.3 168.7 156.6 — Cl (mg) 55.3 92.9 109.4 87.4 - P (mg) 273.1 13.0 203.8 103.6 — Ca (mg) 381.2 2.02 210.6 79.0 — Mg (mg) 27.7 0.23 26.6 24.1 — Mn (mg) 0.008 0.00 0.002 0.00 — Fe (mg) 0.061 0.00 0.12 0.019 - Cu (mg) 0.021 0.007 0.068 0.009 — Zn (mg) 1.61 0.013 0.067 0.011 Sig: Milk and whey permeates from UFl and UF2 respectively were trated and partially demineralised separately by NF3 using two 3838 150-300 Da nanoﬁltration (NF) membranes in series (GEA Filtration, Denmark). For concentration and demineralisation ~1000 kg of UFPl (pH 5.9 at 6.9 °C) was concentrated to 22 % w/w solids content. For concentration and ralisation ~1000 kg of UFP2 (pH 5.6 at 6 °C) was concentrated to 22 % w/w solids content. For concentration of both UFPl and UFP2, NF3 operated within a mass tration factor range of 3.5 — 4 at a temperature of 10 °C. Average permeate ﬂuxes amounted to 9.73 h (for UFPl) and 10.9 kg/mZ/h (for UFP2). The macronutritional and mineral distribution of the liquid retentate and permeate streams from NF3 are presented in table 11.

Post concentration and demineralisation of UFPl and UFP2 by NF3, both retentates were uently indirectly heated to 82 °C using an indirect plate heat exchanger feeding a 250 L jacketed stainless steel . Once the retentate from NF3 was in the storage vessel the pH was adjusted to 7.2 (at 82 °C) using a 30 % w/w NaOH solution, causing the precipitation of calcium salts primarily of phosphate and citrate. The itated solution was held at 82 °C for 20 minutes to maximise the itation reaction followed by cooling to 20 °C using an indirect plate heat exchanger g a second 250 L jacketed stainless steel vessel. The precipitated material was removed from the NF3 retentate stream (post precipitation) by UF3 using two 3838 10 kDa ultraflltration membranes in series (Synder Filtration). UF3 operated within a mass concentration factor of 10 at a temperature of 20 °C.

The macronutritional and mineral distribution of the liquid ate streams from UF3 are presented in table 12. The s according to the invention yielded ~50 % demineralisation in the UF3 retentates compared to UFPl and UFP2 on a dry matter basis.

The liquid retentate streams from UF3 were ed in a stainless steel vessel at 40 °C.

The compounded batch (65 kg total mass) constituted the UFR3 from skim milk and the UFR3 from sweet whey in a mass ratio of 20:80 respectively. The batch was subsequently demineralised using a pilot electrodialysis plant (Pl EDR—Y, MemBrain). The endpoint of the demineralisation was determined based on the relationship between conductivity of the demineralised lactose and the ash content therein (endpoint: conductivity < 1 ms; ash content < 0.75 wt% based on dry matter). Once the endpoint of the demineralisation was reached, the demineralised lactose concentrate stream was cooled to 5 °C followed by determination of total solids t of the ED product as 16.62 % w/w.

Table I]: Compositions ofNFR3s andNFP3s (per 100 g) Component NFR3 (SM) NFP3 (SM) NFR3 (SW) NFP3 (SW) Total solids (g) 20.67 0.32 23.55 0.42 Protein (g) 0.33 0.09 0.37 0.09 e (g) 19.28 0.00 18.59 0.00 ash (g) 1.07 0.24 1.08 0.30 -Na (mg) 58.6 24.0 65.59 33.41 -K(mg) 253.8 94.9 255.94 118.96 - Cl (mg) 68.0 106.9 80.05 132.15 -P(mg) 133.4 5.68 115.36 10.61 - Ca (mg) 125.4 1.80 100.31 1.06 - Mg (mg) 22.9 0.16 27.69 0.16 - Mn (mg) 0.0002 0.0002 0.0002 0.000 - Fe (mg) 0.00 0.0005 0.0231 0.0212 - Cu (mg) 0.006 0.007 0.0075 0.0078 - Zn (mg) 0.023 0.012 0.0402 0.016 Table 12: Compositions of UFR3s and UFP3s (per 100 g) Component UFP3 (SM) UFP3 (SW) ED product Total solids (g) 17.95 19.26 16.62 Protein (g) 0.30 0.35 0.33 Lactose (g) 16.78 17.98 16.17 ash (g) 0.87 0.93 0.12 - Na (mg) 159.9 142.2 18.4 - K (mg) 226.7 230.3 3.0 - Cl (mg) 64.9 79.5 2.4 -P(mg) 66.5 71.5 19.5 - Ca (mg) 15.0 36.9 7.9 - Mg (mg) 16.3 19.8 0.0 - Mn (mg) 0.00 0.00 0.00 - Fe (mg) 0.00 0.0204 0.00 - Cu (mg) 0.016 0.0078 0.00 - Zn (mg) 0.020 0.0168 0.00 Sip—4: The ﬁnal phase in the process was the tion of nutritionally balanced infant/toddler nutrition using the materials prepared in the preceding steps (1 — 3). As such the lactose concentrate solution produced in step 3 (ED product) was used as the liquid stream to which the NFRl and NFR2 were added, giving the desired (legally required) content and ratio of protein (casein/whey) and lactose for tage infant milk (IF), follow on milk (F0) and growing up milk (GUTVI). The streams were blended in the ratios mentioned in table 13. At this stage the liquid concentrate stream comprising demineralised lactose (from ED product), MPC (from NFRl) and WPC (from NFR2) was pre-heated to 50 °C followed by dosing of oil and GOS to meet the nutritional requirements. The liquid concentrate infant formula streams were then heated treated at 85 °C for 5 min in an ct tubular heat exchanger (Mircothermics), homogenised downstream from the heat treatment at ﬁrst and second stage pressures of 125 and 25 bar tively (at 60 °C), followed by evaporation to 55 % w/w solids content in a single effect falling ﬁlm evaporator, operating at 55 °C, and spray drying using a single stage spray dryer equipped with 2 ﬂuid nozzle atomisation operating at an inlet and outlet temperature of 175 °C and 90 °C tively.

The ional composition of the IF, F0 and GUTVI powders ed is outlined in table Note that all components mentioned in table 14, except for the fat and part of the carbohydrates (GOS) originate from the skim milk and sweet whey starting materials. All 2O components in table 14 are either within the acceptable ranges for that component, or are below those acceptable ranges. For those components who’s content is below acceptable, fortiﬁcation would be required to se their content to within acceptable . It is important to note that none of the mentioned components, not even the polyvalent ions, are present above their acceptable range, which would be unacceptable as taking out is impossible, while adding one or a few components may happen straightforward. The possibility of preparing different infant nutritional products, all according to legal standards, demonstrates the versatility and lity of the process according to the invention.

Table 13: Blending ratios, expressed in kg ofliquid concentrate per 100 kg ofdry powder Streams IF FO GUTVI I\FR1 (kg) 43.49 55.74 56.33 I\FR2 (kg) 61.72 47.47 47.97 ED product (kg) 191.83 215.90 208.86 Table 14: Compositions ofIF, FO and GUMpowders (per 100 g) Component IF FO GU1V1 Moisture (g) 1.26 1.68 2.38 Protein (g) 11.5 11.69 11.56 ydrate (g) 56.62 59.23 63 Fat (g) 28.71 25.49 21.3 Ash (g) 1.91 1.91 1.76 - Na (mg) 192 156 171 - K (mg) 290 278 240 - C1 (mg) 88.5 83.5 109.5 - P (mg) 310 300 285 - 804 (mg) 36 33 38 - 1 (mg) 37 36 37 - Se (Hg) 7.7 8.4 6.7 -Ca(mg) 354 351 318 _ Mg (mg) 41 39 34 -211 (mg) 1 1.1 1.06 Carnite (mg) 21.3 23.6 23.8 Choline (mg) 216 231 235 Inositol (mg) 39.9 47.4 50.4 Biotin (Hg) 10.7 11.4 11 Folic acid (Hg) 41.4 38.8 32.1 Pantothenic acid (mg) 2-31 288 2-84 Vitamin B1 (mg) 0.17 0.17 0.17 Vitamin 312 (Mg) 1.38 1.39 1.29 Bitamin B2 (mg) 1.23 1.2 1.27 Vitamin B6 (mg) 0.1205 0.1140 0.1288

Claims

1. A process for obtaining a dry milk formula, comprising the following steps: (a-i) ultrafiltration (UF) of an animal skim milk composition comprising 70 – 90 wt% casein and 10 – 30 wt% whey proteins, based on total protein, and (a-ii) ultrafiltration of an animal whey ition comprising 0 – 25 wt% casein and 75 – 100 wt% whey proteins, based on total protein; or (a-iii) iltration of a e of the itions of (a-i) and (a-ii), (b) preferably combining of the UF retentate originating from step (a-i) with the UF ate originating from step (a-ii); (c) removing polyvalent ions from the UF permeate originating from step (a-i) and/or (a-ii) or (a-iii) to obtain at least one softened UF permeate; (d) combining the at least one softened UF permeate originating from step (c) with a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) to obtain a combined product; and (e-i) drying the combined product originating from step (d) to obtain a dry milk formula, and/or (e-ii) drying any UF retentate originating from step (a-i) and/or (a-ii) or (a-iii) or (b) which is not combined in step (d), and drying any of the softened UF permeates originating from step (c) which is not combined in step (d), ed by combining the dried UF retentate with the dried softened UF permeate to obtain a dry milk formula.

2. The process according to claim 1, wherein the animal skim milk comprises 75 – 85 wt% casein and 15 – 25 wt% whey proteins, based on total protein, preferably about 80 wt% casein and 20 wt% whey protein, preferably the animal skim milk composition of step (a-i) comprises or is animal skim milk.

3. The s according to claim 1, wherein the animal whey composition comprises 0 – 20 wt% casein and 80 – 100 wt% whey proteins, based on total protein, preferably 0 – 10 wt% casein and 90 – 100 wt% whey proteins, more preferably 0 – 5 wt% casein and 95 – 100 wt% whey proteins, preferably the animal whey composition of step (a-ii) comprises or is animal whey.

4. The process according to any one of claims 1 – 3, wherein a UF permeate originating from step (a-i) and a UF permeate originating from step (a-ii) are combined prior to said removal of polyvalent ions of step (c).

5. The process according to any one of claims 1 – 4, wherein a UF retentate originating from step (a-i) and/or (a-ii) is/are concentrated prior to the combining of step (b), (d) or drying of step (e-i) and/or (e-ii); and/or a UF retentate originating from step (a-iii) and/or (b) is/are concentrated prior to the combining of step (d) or drying of step (e-i) and/or (e-ii).

6. The process according to any one of claims 1-5, wherein the UF permeate originating from step (a-i) is combined with a permeate originating from (a-ii) prior to polyvalent ion l of step (c), and preferably trated after polyvalent ion removal of step (c).

7. The process according to any one of claims 1-6, wherein the softened UF permeate ating from step (c) and/or the combined product of step (d) is/are concentrated, prior to the combining of step (d) or the drying of step (e-i) and/or (e-ii).

8. The process ing to any one of claims 5-7, wherein concentration occurs by reverse osmosis and/or nanofiltration.

9. The process according to any one of claims 1 – 8, wherein polyvalent ion removal of step (c) occurs by electrodialysis, ion exchange, e crystallization and/or salt precipitation.

10. The process according to any one of claims 1 – 9, wherein the softened UF permeate of step (c) and/or the UF ate originating from step (a-i) and/or (a-ii) or ) or (b) is/are subjected to monovalent ion removal, preferably by odialysis, nanofiltration, lactose crystallization and/or salt precipitation.

11. The process according to any one of claims 1 – 10, wherein a UF retentate originating from step (a-i) and/or (a-ii), or (a-iii) or (b) and/or a UF permeate originating from step (a-i) and/or (a-ii) or (a-iii), and/or the softened UF permeate originating from step (c) or the combined product of step (d) is/are reated, by direct steam injection (DSI), prior to the drying of step (e-i) and/or (e-ii); preferably the combined product of step (d) is heattreated , preferably by DSI, prior to the drying of step (e-i); or preferably any of the UF retentates of step (e-ii) and/or any of the softened UF permeates of step (e-ii) is heat-treated, preferably by DSI, prior to the drying of step (e-ii).

12. The process according to any one of claims 1 – 11, wherein drying of step (e-i) and/or (eii ) is by spray-drying.

13. The process according to any one of claims 1 – 12, wherein the combined product originating from step (d), the dried combined product of (e-i), and/or the dried UF retentate of (e-ii) which is combined with the dried softened UF permeate of (e-ii) in step (e-ii) is further processed into a nutritional product for providing nutrition to infants.

14. The process according to any one of claims 1 – 13, wherein the animal skim milk composition and animal whey composition of step (a-iii) or the UF retentates originating from step (a-i) and (a-ii) are combined in such a ratio that a product is obtained having a casein:whey n weight ratio of between 75:25 to 30:70, preferably n 64:36 to 36:64, more preferably 60:40 to 40:60 or about 50:50.

15. The process ing to any one of claims 1 – 13, wherein the mixture of the animal skim milk composition and animal whey composition of step ) or the combined UF ate of step (b), or the combined product of step (d), the dry milk formula of (e-i) or the dry milk formula of (e-ii) has a casein:whey protein weight ratio of between 75:25 to 30:70, preferably between 64:36 to 36:64, more preferably 60:40 to 40:60 or about 50:50

16. A modular system, comprising: (1) an ultrafiltration module, sing (1a) an inlet for receiving a first liquid ition and/or a second liquid composition, or a mixture thereof, to a first side of an ultrafiltration membrane, (1b) the ultrafiltration membrane, (1c) a first outlet for discharging an ultrafiltration retentate (UFR) from the first side of the ultrafiltration membrane, and (1d) a second outlet for discharging an ultrafiltration permeate (UFP) from the second side of the ultrafiltration ne; (2) a polyvalent ion removal module, comprising (2a) an inlet for receiving the UFP originating from the ultrafiltration module (1), (2b) means for removing polyvalent ions, and (2c) an outlet for discharging a softened UFP; (3) at least one mixing module, comprising (3a) a first inlet for ing the softened UFP originating from the polyvalent ion removal module (2), (3b1) a second inlet for receiving the first liquid composition or an UFR of the first liquid composition and a third inlet for receiving the second liquid composition or an UFR of the second liquid, or (3b2) a second inlet for receiving the mixture of the first liquid composition and the second liquid composition or an UFR of the first liquid composition and an UFR of the second liquid composition, and (3c) an outlet for discharging a recombined product; and (4) a drying module, comprising (4a1) a first inlet for receiving the UFR originating from the ultrafiltration module (1) and a second inlet for receiving the softened UFP originating from the polyvalent ion removal module (2), or (4a2) an inlet for receiving the recombined t originating from the mixing module (3), (4b) drying means, and (4c) an outlet for rging a dried ition.

17. A process ing to claim 1, substantially as herein described or exemplified with reference to the accompanying drawings.

18. A system according to claim 16, substantially as herein described or exemplified with reference to the anying drawings. WO 63493