METHOD FOR PROCESSING A DAIRY PROTEIN COMPOSITION IN ORDER TO PRODUCE A LACTOSE-RICH LIQUID COMPOSITION

Abstract

A method for the processing a dairy protein composition in order to obtain a lactose-rich liquid composition, including an ultrafiltration step (ii) in order to obtain an ultrafiltration permeate and an ultrafiltration retentate; followed by a processing step (iv) on ion-exchange resins, including at least one pass including percolation over a cationic resin followed by percolation over an anionic resin.

Claims

1. Method for processing a dairy protein composition in order to obtain a lactose-rich liquid composition, wherein the method comprises the steps: (i) providing a dairy protein composition; (ii) ultrafiltration of said dairy protein composition in order to obtain an ultrafiltration permeate and an ultrafiltration retentate; (iii) a step of at least partial demineralisation, taking place one or more of before ultrafiltration step (ii) and after ultrafiltration step (ii); (iv) one step of processing, on ion-exchange resins, said at least partially demineralised ultrafiltration permeate, comprising at least one pass comprising percolation over a cationic resin followed by percolation over an anionic resin.

2. Method according to claim 1, wherein step (iv) comprises at least two passes.

3. Method according to claim 1, wherein step (iv) of processing, on ion-exchange resins, the at least partially demineralised ultrafiltration permeate, comprises at least one pass comprising percolation over a strong cationic resin followed by percolation over a weak anionic resin.

4. Method according to claim 1, wherein the conductivity of the ultrafiltration permeate (ii) at the inlet to step (iv) is less than or equal to 3 mS/cm.

5. Method according to claim 1, wherein the ultrafiltration step (ii) comprises the use of one or more ultrafiltration membranes, each having a minimum cut-off threshold greater than or equal to 1000 Daltons and less than or equal to 10,000 Daltons.

6. Method according to claim 1, wherein the dairy protein composition at the inlet of ultrafiltration step (ii) has a level of demineralisation greater than or equal to 70%.

7. Method according to claim 1, wherein the ultrafiltration permeate at the inlet of processing step (iv) on the ion-exchange resins has a level of demineralisation greater than or equal to 80%.

8. Method according to claim 1, wherein the at least partial demineralisation step (iii) comprises a step (iiia) of substituting cations by hydrogen ions H.sup.+.

9. Method according to claim 8, wherein the cation substitution step (iiia) is an electrodialysis step of cationic substitution carried out on an electrodialyser comprising cells each comprising three compartments.

10. Method according to claim 8, wherein the demineralisation step (iii) comprises a step (iiib) of substituting anions by hydroxyl ions OH.sup.−, and wherein said step (iiib) is carried out on an electrodialyser comprising cells each comprising three compartments.

11. Method according to claim 1, wherein the at least partial demineralisation step (iii) comprises one or more of an electrodialysis step and a nanofiltration step.

12. Method according to claim 1, comprising a step taking place after step (iv), comprising at least one pass comprising a percolation over an absorbent resin.

13. Method according to claim 1, comprising a step (v) of nanofiltration carried out after the step (iv) of processing on ion-exchange resins.

14. Method according to claim 1, wherein the ratio of the dry mass of lactose over the total dry mass of the resulting lactose-rich liquid composition is greater than or equal to approximately 90%.

15. Method according to claim 1, comprising a step iii) of demineralisation carried out before the ultrafiltration step (ii), and wherein at least partially demineralised ultrafiltration retentate obtained at the end of ultrafiltration step (ii) is stable at a temperature higher than or equal to 100° C.

16. Method according to claim 1, wherein the ratio of the dry mass of the total nitrogenous matter (TNM) over the total dry mass of the ultrafiltration retentate obtained in step (ii) is greater than or equal to approximately 50%.

17. Method according to claim 1, wherein the ratio of the dry mass of ash over the total dry mass of the ultrafiltration retentate obtained in step (ii) is less than 6%.

18. Method according to claim 1, wherein the dairy protein composition of step (i) is chosen among: milk, in particular skimmed milk, whey and a mixture thereof.

19. Method according to claim 18, wherein the dairy protein composition is chosen among: acid whey, sweet whey, native whey and a mixture thereof.

20. Method according to claim 1, comprising a step of concentration by evaporation and drying, carried out after the step (iv) of processing on ion-exchange resins, in order to obtain lactose in solid form.

21. A lactose-rich liquid composition obtained by the method according to claim 1, wherein the ratio of the dry mass of lactose over the total dry mass of said lactose-rich liquid composition is greater than or equal to 90%.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0230] The disclosure will be better understood upon reading the following description of an embodiment of the disclosure, given solely as non-limiting example and with reference to the attached drawings, wherein:

[0231] FIG. 1 illustrates the method for processing a dairy protein composition according to the disclosure;

[0232] FIG. 2 illustrates the processing of the ultrafiltration permeate of FIG. 1 on ion-exchange resins, step (iv).

DETAILED DESCRIPTION

[0233] In FIG. 1, the dairy protein composition 10 is fed to an ultrafiltration unit 20, in particular including a concentration subunit and a diafiltration subunit, for forming a UF retentate 30 rich in serum proteins and a UF permeate 40 rich in lactose. In this example, the UF membranes have precisely one cut-off level between 1000 Daltons and 10000 Daltons, preferably between 4000 and 6000 Daltons.

[0234] The dairy protein composition (DPC) 10 can be at least partially demineralised during a demineralisation step (iii) before ultrafiltration step (ii).

[0235] The UF permeate 40 obtained in step (ii) can be demineralised, as an alternative to the demineralisation step taking place before UF step (ii) or in addition thereto, during a demineralisation step (iii) taking place after UF step (ii) and before step (iv) on the ion-exchange resins in order to achieve a satisfactory level of demineralisation enabling the recovery of a lactose-rich liquid composition after step iv), for which, in particular, the dry mass fraction of sugar(s), in particular of lactose, with respect to its total dry mass is greater than or equal to 90%.

[0236] The method according to the disclosure can also include a reverse osmosis step in order to increase the dry mass fraction of the UF permeate (ii), preferably carried out after a demineralisation step (iii).

[0237] The UF permeate 40 is percolated as illustrated in FIG. 2 on columns including ion-exchange resins, in particular in two passes 80 and 90. During the first pass 80, the partially demineralised UF permeate 40 is percolated over a column including a, preferably strong, cationic resin 50, then is percolated over a column including a, preferably weak, anionic resin 60. During the second pass, the partially demineralised UF permeate 40 leaving the first pass 80, is again percolated over a column including a, preferably strong, cationic resin 55, then on a column including a, preferably weak, anionic resin 65. The UF permeate 40 leaving the two passes 80 and 90 can also undergo a percolation over a column including an absorbent resin 70 in order to remove the colouring of the UF permeate 40, in particular to remove the riboflavin responsible for the colouring. This step does not significantly change the mass fraction of lactose.

[0238] The absorbent resin can be, for example, an absorbent resin with a highly porous styrene divinyl benzene matrix with sulfonic groups, the pore size of which is greater than or equal to 350 Å, and having an exchange capacity of order 1.

[0239] A lactose-rich liquid composition is recovered at the end of step iv) and in this specific example after the processing on an absorbent resin. This lactose-rich and generally sugar-rich liquid composition has a very large mass fraction of lactose with respect to its total dry mass. In certain cases, this composition can further include galactose, depending on the initial dairy protein composition. The lactose-rich liquid composition then undergoes a nanofiltration step v) in order to remove or reduce the mass fraction of galactose, and thus increasing the mass fraction of lactose. This nanofiltration step v) can take place after the processing on the absorbent resin.

[0240] The strong cationic resins 50 and 55 can be, for example, porous strong styrene cationic resins, the bead size of which is 0.45 mm minimum, the water content of which is less than or equal to 58% and the exchange capacity 1.8 eq/I. It may be a resin supplied by the companies Mitsubishi, Dao, or Purolite.

[0241] The weak anionic resins 60 and 65 can be, for example, porous weak styrene anionic resins, the bead size of which is 0.40 mm minimum, the water content of which is less than or equal to 58% and the exchange capacity 1.6 eq/I minimum.

[0242] The dairy protein composition can be a sweet whey, an acid whey, or a native whey.

[0243] The dairy protein composition can the milk, in particular skimmed milk. In this case, the ultrafiltration retentate 40 in step (ii) is rich in serum proteins and in caseins.

[0244] In non-limited examples, a strong cationic resin, in particular suitable to carry out the step (iv), may be sold by Mitsubishi or Dow or Purolite, in particular is of Relite RPS type, or FPC22 type, or PPC150S type.

[0245] In non-limited examples, a weak anionic resin, in particular suitable to carry out the step (iv), may be sold by Mitsubishi or Dow or Purolite, in particular is of RAM1S type, or FPA54 type or A133S type.

[0246] In non-limited examples, an adsorbent resin, in particular suitable to carry out the present method, may be sold by Mitsubishi or Dow or Purolite, in particular is of Relite RAD/F type, or MN500 type.

Example 1 According to the Disclosure for Processing an Acid Whey with a Partial Demineralisation (iii) Before UF Step (ii)

[0247] a The acid whey of step i) has undergone a demineralisation step (iii) before ultrafiltration step (ii). The partially demineralised acid whey, at the inlet to ultrafiltration step (ii), has a pH of approximately 6; a conductivity less than or equal to 5 mS/cm, a level of demineralisation of 74%, a dry mass extract of approximately 18%, a dry mass fraction of TNM of approximately 13%, a mass fraction of ash of approximately 2%, a dry mass fraction of lactose of order 86%, a mass fraction of cations (Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 1.5%, and a mass fraction of anions (CI.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.5%.

[0248] This partially demineralised acid whey undergoes a UF step ii), then the UF permeate obtained is percolated on ion-exchange resins in step iv). The feed pressure of the whey during the UF in step ii) is of order 4 bars. The temperature of the partially demineralised whey at the inlet to UF step (ii) is of order 10° C., this temperature is maintained during UF step ii) and during step iv) on the ion-exchange resins. The preceding mass fractions are calculated with respect to the total dry mass of the partially demineralised acid whey at the inlet to UF step (ii).

[0249] b The UF permeate of the partially demineralised acid whey obtained at the outlet of the UF step (ii) has a pH of approximately 6; a dry mass extract of approximately 13%, a conductivity less than or equal to 2 mS/cm, a dry mass fraction of TNM of approximately 4%, a mass fraction of ash less than 2%, a mass fraction of cations (Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.9%, a mass fraction of anions (Cl.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.2%, and a mass fraction of lactose of order 93%. The preceding mass fractions are calculated with respect to the total dry mass of the UF permeate at the outlet of UF step (ii).

[0250] c The UF retentate of the partially demineralised acid whey obtained at the outlet of UF step (ii), has a pH of between 5.5 and 5.9; a dry mass extract of approximately 15%, a dry mass fraction of TNM of approximately 50%, a mass fraction of ash less than approximately 2.8%, a mass fraction of cations (Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 1.5%, a mass fraction of anions (Cl.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.3%, and a mass fraction of lactose of order 50%. The preceding mass fractions are calculated with respect to the total dry mass of the UF retentate at the outlet of UF step (ii).

[0251] d After a double pass over the ion-exchange resins of the UF permeate during step (iv), such as the double pass 80, 90, the lactose-rich liquid composition that is recovered after step iv), and optionally the passage over at least one column of absorbent resin, has a pH of order 6.8, a dry mass extract of approximately 10%, a conductivity less than or equal to 10 μS/cm, a dry mass fraction of TNM less than approximately 0.3%, a mass fraction of ash less than or equal to 0.1%, a mass fraction of cations (Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.001%, and a mass fraction of anions (Cl.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.001%, and a mass fraction of lactose of order 99.5%. The preceding mass fractions are calculated with respect to the total dry mass of the lactose-rich liquid composition obtained.

Example 2 According to the Disclosure for Processing a Sweet Whey with a Partial Demineralisation (iii) Before UF Step (ii)

[0252] a—The sweet whey of step i) has undergone a demineralisation step (iii) before ultrafiltration step (ii). The partially demineralised sweet whey at the inlet of ultrafiltration step (ii) and used hereafter has a pH of 6.8; a level of demineralisation of 90%, a dry mass extract of approximately 20%, a dry mass fraction of TNM of approximately 13%, a mass fraction of non-protein nitrogenous matter less than 2%, a mass fraction of ash of approximately 1%, a mass fraction of lactose of 80%. The preceding mass fractions are calculated with respect to the total dry mass of the partially demineralised sweet whey at the inlet to UF step (ii).

[0253] This partially demineralised sweet whey undergoes a UF step ii), then the UF permeate obtained is percolated on ion-exchange resins in step iv). The feed pressure of the whey during the UF in step ii) is of order 4 bars. The temperature of the partially demineralised whey at the inlet to UF step (ii) is of order 10° C., this temperature is maintained during UF step ii) and during step iv) on the ion-exchange resins.

[0254] b—The UF permeate of the partially demineralised acid whey obtained at the outlet of UF step (ii), has a pH of approximately 6.5; a dry mass extract of approximately 13%, a conductivity of order 600 μS/cm, a dry mass fraction of TNM of approximately 1%, a mass fraction of non-protein nitrogenous matter less than 1%, a mass fraction of ash less than or equal to 0.6%, a mass fraction of cations (Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.3%, a mass fraction of anions (Cl.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.1%, and a mass fraction of lactose of 91%. The level of demineralisation of the UF permeate is of order 99%. The preceding mass fractions are calculated with respect to the total dry mass of the UF permeate at the outlet of UF step (ii).

[0255] c—The UF retentate of the partially demineralised sweet whey obtained at the outlet of UF step (ii) has a pH less than or equal to 7; a dry mass extract of approximately 20%, a dry mass fraction of the TNM of approximately 50%, a mass fraction of non-protein nitrogenous matter less than or equal to 5%, a mass fraction of ash less than or equal to approximately 0.5%. The preceding mass fractions are calculated with respect to the total dry mass of the UF retentate at the outlet of UF step (ii).

[0256] d—After a double pass over the ion-exchange resins of the UF permeate, such as the double pass 80, 90, the lactose-rich liquid composition obtained after step iv), and optionally the passage over at least one column of absorbent resin, has a pH of between 5 and 6, a dry mass extract of approximately 13%, a conductivity less than or equal to 5 μS/cm, a dry mass fraction of TNM less than approximately 0.4%, a mass fraction of non-protein nitrogenous matter less than or equal to 0.1%, a mass fraction of ash less than or equal to 0.1%, a mass fraction of cations (Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.012%, and a mass fraction of anions (Cl.sup.−, NO.sub.3.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.015%, and a mass fraction of lactose of order 99.8%. After a single pass over the resins 80, the mass fraction of lactose is of order 99%, which is less than the value of 99.8% obtained after a double pass. The level of removal of glycomacropeptides and riboflavin is close to 100%. The preceding mass fractions are calculated with respect to the total dry mass of the lactose-rich liquid composition obtained.

Example 3 According to the Disclosure for Processing a Native Whey with a Demineralisation (iii) After UF Step (ii)

[0257] a—A native whey (step i) undergoes an ultrafiltration step (ii) then reverse osmosis to preconcentrate it. The ultrafiltration permeate of the preconcentrated native whey has a pH of 6.0; a conductivity less than or equal to 10.5 mS/cm, a dry mass extract of approximately 15%, a dry mass fraction of TNM of approximately 3%, a mass fraction of ash of approximately 9%, a dry mass fraction of lactose of order 84%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) calculated with respect to the total dry mass less than or equal to 3.6%, and a mass fraction of anions (CI.sup.−, P—PO.sub.4.sup.3−, S—SO.sub.4.sup.2−) less than or equal to 2.3%. This ultrafiltration permeate (40) undergoes a demineralisation step (iii) by electrodialysis iii) (the cells of which include two compartments), then is percolated on ion-exchange resins in step iv). The temperature of the ultrafiltration permeate during electrodialysis step (iii) is of order 30° C., this temperature is lowered to 10° C. during step iv) on the ion-exchange resins. The preceding mass fractions are calculated with respect to the total dry mass of ultrafiltration permeate at the inlet of demineralisation step (iii).

[0258] b The UF permeate of the partially demineralised native whey obtained at the outlet of electrodialysis step (iii) has a pH of approximately 5; a dry mass extract of approximately 14%, a conductivity less than or equal to 0.4 mS/cm, a dry mass fraction of TNM of approximately 2%, a mass fraction of ash less than 1%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.13%, a mass fraction of anions (CI.sup.−, P—PO.sub.4.sup.3−, S—SO.sub.4.sup.2) less than or equal to 0.27%, and a dry mass fraction of lactose of order 97%. The level of demineralisation of the UF permeate after step (iii) is of order 96%. The preceding mass fractions are calculated with respect to the total dry mass of the UF permeate at the outlet of demineralisation step (iii).

[0259] c—After a double pass over the ion-exchange resins of the UF permeate during step (iv), such as the double pass 80, 90, the lactose-rich liquid composition obtained after step iv), and optionally the passage over at least one column of absorbent resin, has a pH of order 5, a dry mass extract of approximately 13%, a conductivity less than or equal to 5 μmS/cm, a dry mass fraction of TNM less than approximately 0.8%, a mass fraction of ash less than or equal to 0.1%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.001%, and a mass fraction of anions (Cl.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2) less than or equal to 0.001%, and a dry mass fraction of lactose of order 99.5%. The preceding mass fractions are calculated with respect to the total dry mass of the lactose-rich liquid composition obtained.

Example 4 According to the Disclosure for Processing a Native Whey with a Demineralisation (iii) After UF Step (ii)

[0260] a—The native whey (i) undergoes an ultrafiltration step (ii) and reverse osmosis in order to preconcentrate it. The ultrafiltration permeate of the preconcentrated native whey has a pH of approximately 6; a conductivity less than or equal to 10.5 mS/cm, a dry mass extract of approximately 17%, a dry mass fraction of TNM of approximately 3%, a mass fraction of ash of approximately 9%, a dry mass fraction of lactose of order 84%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) calculated with respect to the total dry mass less than or equal to 3.6%, and a mass fraction of anions (Cl.sup.−, P—PO.sub.4.sup.3−, S—SO.sub.4.sup.2−) less than or equal to 2.3%. This ultrafiltration permeate (40) undergoes a demineralisation step by acid electrodialysis iii) and is then percolated on ion-exchange resins in step iv). The demineralisation step iii) includes a chain of three electrodialyses: cation substitution electrodialysis (CSE) of cations by hydrogen ions H.sup.+ (iiia) in three compartments, followed by an electrodialysis with two demineralisation compartments, and followed by an anion substitution electrodialysis (ASE) of anions by hydroxyl ions (iiib) in three compartments. The temperature of the ultrafiltration permeate during electrodialysis step (iii) is of order 30° C., this temperature is lowered to 10° C. during step iv) on the ion-exchange resins. The preceding mass fractions are calculated with respect to the total dry mass of ultrafiltration permeate at the inlet of demineralisation step (iii).

[0261] b—The UF permeate of the whey undergoes a first CSE electrodialysis (iiia) that enables substituting of the cations by protons and thus working in an acid process. The whey at the outlet of the CSE (iiia), has a pH of approximately 1.5; a dry mass extract of approximately 16%, a conductivity of approximately 12 mS/cm, a dry mass fraction of TNM of approximately 2%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.8%, a mass fraction of anions (Cl.sup.−, P—PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 1.9%, and a mass fraction of lactose of order 95%. The acidified whey then undergoes a demineralisation of approximately 90% by conventional electrodialysis ED with two compartments. The whey at the outlet of ED has a pH of approximately 2.6; a dry mass extract of approximately 16%, a conductivity of approximately 1 mS/cm, a dry mass fraction of TNM of approximately 2%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.13%, a mass fraction of anions (Cl.sup.−, P—PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.19%, and a dry mass fraction of lactose of order 97%. The partially demineralised whey then undergoes a demineralisation of approximately 96% by an anionic substitution electrodialysis ASE (iiib). The whey at the outlet of ASE (iiib) has a pH of approximately 8; a dry mass extract of approximately 16%, a conductivity of approximately 0.4 mS/cm, a dry mass fraction of TNM of approximately 2%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.13%, a mass fraction of anions (Cl.sup.−, P—PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.15%, and a dry mass fraction of lactose of order 98%.

[0262] c—After a double pass over the ion-exchange resins of the UF permeate during step (iv), such as the double pass 80, 90, the lactose-rich liquid composition obtained after step iv), and optionally the passage over at least absorbent resin, has a pH of order 5, a dry mass extract of approximately 13%, a conductivity less than or equal to 5 μmS/cm, a dry mass fraction of TNM less than approximately 0.8%, a mass fraction of ash less than or equal to 0.1%, a mass fraction of cations (Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+) less than or equal to 0.001%, and a mass fraction of anions (Cl.sup.−, PO.sub.4.sup.3−, SO.sub.4.sup.2−) less than or equal to 0.001%, and a dry mass fraction of lactose of order 99.5%. The preceding mass fractions are calculated with respect to the total dry mass of the lactose-rich liquid composition obtained.

[0263] Demineralisation step (iii) carried out in examples 1 and 2 can be any demineralisation step known to a person skilled in the art enabling demineralisation of the dairy protein composition at the inlet of UF step (ii) and/or after UF step (ii) in order to lower the dry mass fraction minerals of the UF permeate at the inlet of step (iv) including at least one pass over ion-exchange resins. This demineralisation step can be carried out in a non-limiting manner as described in the present text or again as described in patent EP 1.053.685 B1 or WO 2020/207894 or again as described in examples 3 and 4.