Methods and compositions involving whey protein isolates

• US 10,638,775 B2
• Filed: 08/03/2018
• Issued: 05/05/2020
• Est. Priority Date: 07/19/2010
• Status: Active Grant

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Etzel, Mark R., Root, Thatcher, Arunkumar, Abhiram, Gemili, Seyhun
• Primary Examiner(s): Tarazano, D. Lawrence
• Assistant Examiner(s): Dubois, Philip A
• Application Number:
  US16/054,196
• Publication Number:
  US 20180343890A1
• Time in Patent Office: 641 Days
• Field of Search: None
• CPC Class Codes: A23J 1/205 from whey, e.g. lactalbumine
• CPC Class Codes: A23J 3/08 Dairy proteins
• CPC Class Codes: A23V 2002/00 Food compositions, function of food ingredients or processes for food or foodstuffs
• CPC Class Codes: A23V 2200/06 pH modification agent
• CPC Class Codes: A23V 2250/54242 Alpha lactalbumin
• CPC Class Codes: A23V 2250/54244 Beta lactoglobulin
• CPC Class Codes: A23V 2250/5434 Immunoglobulines
• CPC Class Codes: A23V 2250/5438 Sialic acid, glycomacroprotein
• CPC Class Codes: A23V 2300/18 Fractionation
• CPC Class Codes: A23V 2300/34 Membrane process

Abstract

The present invention concerns methods of isolating milk proteins. Methods of the invention include charged ultrafiltration processes that use variations in pH to further separate protein species.

Claims

1. A method for fractionating a protein mixture, the method comprising:

(a) adjusting the pH of the protein mixture based on the isoelectric point of a protein of interest in the protein mixture, thereby rendering a net charge of about zero on the protein of interest;

(b) adjusting conductivity of the protein mixture such that proteins other than the protein of interest are rejected by a charged ultrafiltration membrane; and

(c) contacting said mixture with a charged ultrafiltration membrane to achieve a first permeate and a first retentate, wherein said ultrafiltration membrane has a pore size at least 10×

greater than the molecular mass of at least one of the proteins other than the protein of interest, and has a pore size of between about 86 kDa and about 1,600 KDa, wherein said first permeate comprises an increased ratio of the protein of interest as compared to the protein mixture.

2. The method of claim 1, wherein the protein mixture is a milk protein or a whey protein mixture.

3. The method of claim 1, further comprising subjecting the first permeate to a second charged ultrafiltration to achieve a second permeate and a second retentate.

4. The method of claim 1, further comprising subjecting the first retentate to a second charged ultrafiltration to achieve a second retentate and a second permeate.

5. The method of claim 3, wherein said second retentate is recycled into another protein mixture for additional charged ultrafiltration.

6. The method of claim 4, wherein said second permeate is recycled into another protein mixture for additional charged ultrafiltration.

7. The method according to claim 1, wherein the ultrafiltration achieves a purity of about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99%.

8. The method according to claim 1, wherein the ultrafiltration achieves a yield of about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99%.

9. The method of claim 1, wherein the ultrafiltration membrane is positively-charged or negatively-charged.

10. The method of claim 1, wherein the conductivity is adjusted to 3-10 mS/cm, in particular to 3-6 mS/cm.

11. The method of claim 1, wherein GMP is separated from ALA, IgG, or BLG;

or wherein ALA is separated from IgG or BLG;

or wherein BLG is separated from IgG.

12. The method of claim 1, wherein said charged ultrafiltration is effected by a multistage cross-flow positively-charged of ultrafiltration membrane.

13. The method according to claim 3, wherein the ultrafiltration achieves a purity of about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99%.

14. The method according to claim 4, wherein the ultrafiltration achieves a purity of about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99%.

15. The method according to claim 3, wherein the ultrafiltration achieves a yield of about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99%.

16. The method according to claim 4, wherein the ultrafiltration achieves a yield of about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99%.

17. A method for separating glycomacropeptide (GMP) from alpha-lactalbumin (ALA), GMP from immunoglobulin G (IgG), GMP from beta-lactoglobulin (BLG), ALA from IgG, or BLG from IgG, the method comprising:

(a) adjusting pH of a protein mixture comprising two or more of GMP, ALA, GLG, or IgG based on an isoelectric point of one of GMP, ALA, GLG, or IgG present in the protein miture, thereby rendering a net charge of about zero on one of GMP, ALA, GLG, or IgG present in the protein mixture;

(b) adjusting conductivity of the protein mixture such that proteins selected from the group consisting of GMP, ALA, BLG, and IgG, other than the protein of step (a) that has a net charge of about zero, are rejected by a charged ultrafiltration membrane; and

(c) contacting the protein mixture of step (b) with a charged ultrafiltration membrane tp acjoeve a forst permeate and a first retentate, wherein the ultrafiltration membrane has a pore size at least 10×

greater than the molecular mass of at least one of GMP, ALA, BLG, or IgG, other than the protein of step (a) that has a net charge of about zero, and has a pore size of between about 86 kDa and about 1,600 kDa, wherein the first permeate comprises an increased ratio of the protein of step (a) that has a net charge of about zero as compared to the protein mixture.