Process for demineralising a milk protein composition, milk protein composition obtainable by said process, and facility for implementing said process

1 . A process for manufacturing a demineralised milk protein composition (MPC2), wherein it comprises the following steps:

(i)—providing a milk protein composition (MPC) comprising anions, monovalent cations and divalent cations;

(ii)—electrodialysis of the milk protein composition (MPC) on a first electrodialyser, said first electrodialyser comprising unit cells, each unit cell comprises three compartments: a first compartment supplied with at least acid salt, a second compartment delimited between two cationic membranes and receiving said milk protein composition (MPC), and a third compartment, wherein each unit cell is configured to substitute at least a part of the monovalent cations and divalent cations of the milk protein composition (MPC) by hydrogen ions H + coming from the first compartment in the milk protein composition (MPC) to obtain an at least partially demineralised and acidified milk protein composition (MPC1) having a pH less than or equal to 4, wherein step (ii) is a step of substitution exclusively of cations;

(iii)—electrodialysis of the milk protein composition (MPC1) obtained in step (ii) on a second electrodialyser, said electrodialysis step (iii) comprises the extraction of both anions and cations; wherein said process comprises the addition of at least one basic solution to the milk protein composition during at least one of the following: during step (iii); during step (iii) and after step (iii); after step (iii), to raise the pH of the milk protein composition (MPC1);

(iv)—recovering the demineralised milk protein composition (MPC2).

2 . The manufacturing process according to claim 1 , wherein the addition of the basic solution is carried out during at least one part of the electrodialysis step (iii) concomitantly with the extraction of ions.

3 . The manufacturing process according to claim 1 , wherein the addition of the basic solution to the milk protein composition is carried out when the milk protein composition has a conductivity less than or equal to 1 mS/cm, and has a pH greater than or equal to 3.

4 . The manufacturing process according to claim 1 , wherein after the addition of the basic solution, the milk protein composition has a pH greater than or equal to 4.5.

5 . The manufacturing process according claim 1 , wherein the milk protein composition recovered in step (iv) (MPC2) comprises phosphate ions (H 2 PO 4 31 , HPO 4 2− , PO 4 3− ), for which the mass of phosphorus is greater than or equal to 110 mg for 100 g of total dry mass of said recovered milk protein composition (MPC2).

6 . The manufacturing process according to claim 1 , wherein the milk protein composition recovered in step (iv) (MPC2) comprises sodium or potassium ions, the mass of which is greater than or equal to 20 mg for 100 g of total dry mass of said recovered milk protein composition (MPC2).

7 . The manufacturing process according to claim 1 , wherein it comprises a treatment step (v) of at least part of the salt(s) selected from the following salts:

the salt(s) derived directly from electrodialysis step ii),

the salt(s) derived indirectly from electrodialysis step ii),

the salt(s) derived directly from electrodialysis step iii),

the salt(s) derived indirectly from electrodialysis step iii),

the salt(s) from a preliminary demineralisation step carried out on the milk protein composition before step i),

a mixture of the latter,

said treatment step (v) being configured to produce one or more acid salts on the one hand, and

one or more basic salts on the other hand.

8 . The manufacturing process according to claim 7 , wherein treatment step (v) consists of an electrodialysis step carried out on a bipolar membrane electrodialyser.

9 . The manufacturing process according to claim 8 , wherein the bipolar membrane electrodialyser, in step (v), comprises unit cells comprising three compartments A, B and C, compartments A and B are supplied with water and compartment C is supplied with at least one salt.

10 . The manufacturing process according to claim 9 , wherein at least one salt obtained during treatment step (v) is supplied to one of the three compartments of the electrodialyser in step ii).

11 . The manufacturing process according to claim 7 , wherein the basic solution comprises, at least in part, at least one basic salt obtained during treatment step (v).

12 . The manufacturing process according to claim 1 , wherein the basic solution is derived, at least in part, from the recycling of an effluent derived from at least one of the following: the step ii); the step ii) and the step iii); and step iii).

13 . The manufacturing process according to claim 1 , wherein the milk protein composition is selected from the list comprising: whey; a milk ultrafiltration permeate; a milk microfiltration permeate; a whey ultrafiltration retentate, a whey ultrafiltration permeate; a retentate of a milk microfiltration permeate ultrafiltration a permeate of a milk microfiltration permeate ultrafiltration; or a mixture thereof.

14 . The manufacturing process according to claim 1 , wherein the basic solution is added in the compartments of the electrodialyser of step (iii) comprising the milk protein composition MPC1.

15 . The manufacturing process according to claim 1 , wherein the addition is carried out on stopping the electrodialyser (iii), then adding the basic solution to the MPC1, then restarting the electrodialyser.

16 . The manufacturing process according to claim 2 , wherein the addition of the basic solution is carried out during at least one part of electrodialysis step (iii) under the application of an electric field.

17 . The manufacturing process according to claim 1 , wherein the basic solution is a sodium hydroxide (NaOH) solution or a potassium hydroxide (KOH) solution or a blend thereof.

18 . The manufacturing process according to claim 1 , wherein the first compartment of the first electrodialyser is delimited between a membrane permselective to monovalent cations, or an anionic membrane, and the cationic membrane of the second compartment.

19 . The manufacturing process according to claim 1 , wherein the third compartment of the first electrodialyser is delimited between the cationic membrane of the second compartment and a membrane permselective to monovalent cations, or an anionic membrane.

20 . The manufacturing process according to claim 1 , wherein the first compartment of the first electrodialyser is supplied with hydrochloric acid salt and the third compartment is supplied with at least one chloride salt of monovalent cation or with water.