Methods involving whey protein isolates
View Patent ↗The present invention concerns methods and compositions that involve whey protein isolates. Methods of the invention include purification processes for preparing whey proteins that are substantially nondenatured across a range of pH, including their isoelectric points. As such, they have low turbidity in solution across a wide range of pH values. Whey protein isolates can be integrated into compositions and solutions that have nutritional, pharmaceutical, and other applications.
1. A method for preparing nondenatured whey proteins comprising:
a) contacting whey proteins to a cation exchange support under conditions to allow whey proteins to be adsorbed to the support;
b) directionally flowing a buffered desorption solution having a pH of more than 9.5 across the support to desorb adsorbed whey proteins and to form a moving interface between desorbed whey proteins in a mobile phase and remaining adsorbed whey proteins, wherein the desorbed whey proteins are nondenatured; and
c) collecting the desorbed nondenatured whey proteins,
wherein the buffered desorption solution that contacts the support is more than pH 9.5.
2. The method of claim 1 , wherein the buffered desorption solution has a pH between 9.5 and about 13.
3. The method of claim 2 , wherein the buffered desorption solution has a pH of about 11.5.
4. The method of claim 1 , wherein the support is on a bead or a membrane.
5. The method of claim 4 , wherein the support is on a bead.
6. The method of claim 5 , wherein the bead is in a resin or gel.
7. The method of claim 6 , wherein the resin or gel is in a non-reacting structure.
8. The method of claim 7 , wherein the non-reacting structure is a column.
9. The method of claim 5 , wherein the beads have a diameter between about 30 μm and about 500 μm.
10. The method of claim 9 , wherein the beads have a diameter between about 100 μm and about 300 μm.
11. The method of claim 1 , wherein the buffer is selected from the group consisting of phosphate and citrate.
12. The method of claim 11 , wherein the buffer is phosphate.
13. The method of claim 1 , wherein the concentration of buffer in the buffered desorption solution is between about 0.5 mM and about 100 mM.
14. The method of claim 13 , wherein the concentration of buffer in the buffered desorption solution is less than about 20 mM.
15. The method of claim 1 , wherein the buffered desorption solution comprises salt.
16. The method of claim 15 , wherein the salt is a sodium salt.
17. The method of claim 16 , wherein the sodium salt is sodium phosphate.
18. The method of claim 17 , wherein the buffered desorption solution further comprises sodium chloride.
19. The method of claim 1 , wherein the buffered desorption solution flows across the support at a flow rate between about 10 support volumes per hour and about 200 support volumes per hour.
20. The method of claim 19 , wherein the flow rate is between about 50 support volumes per hour and about 150 support volumes per hour.
21. The method of claim 1 , wherein whey proteins are in a solution having a pH between about 1 and about 7 when contacted with the support.
22. The method of claim 21 , wherein whey proteins are in a solution having a pH between about 4 and 7 when contacted with the support.
23. The method of claim 1 , further comprising subjecting the desorbed whey proteins to ultrafiltration.
24. The method of claim 1 , further comprising drying the desorbed whey proteins.
25. The method of claim 24 , wherein desorbed whey proteins is spray dried.
26. The method of claim 1 , wherein the desorbed whey proteins have a turbidity below about 400 NTU across a pH range between about 2 and about 8 when in a solution comprising 25 mg/ml of desorbed whey proteins.
27. The method of claim 26 , wherein the desorbed whey proteins have a turbidity below about 200 NTU across a pH range between about 2 and about 8 when in a solution comprising 25 mg/ml of desorbed whey proteins.
28. The method of claim 27 , wherein the desorbed whey proteins have a turbidity below about 100 NTU across a pH range between about 2 and about 8 when in a solution comprising 25 mg/ml of desorbed whey proteins.