Method for decaffeinating an aqueous solution using molecularly imprinted polymers

• US 6,322,834 B1
• Filed: 09/28/1999
• Issued: 11/27/2001
• Est. Priority Date: 09/28/1999
• Status: Expired due to Term

• Current Assignee: The Decaf Company, LLC
• Original Assignee: Anna Madeleine Leone
• Inventors: Leone, Anna Madeleine
• Primary Examiner(s): Weier, Anthony J.
• Application Number:
  US09/408,486
• Time in Patent Office: 791 Days
• Field of Search: 426/422, 426/597, 426/424, 426/435
• US Class Current: 426/422
• CPC Class Codes: A23F 3/385 using flocculating, precipitating, adsorbing or complex-forming agents, or ion-exchangers
• CPC Class Codes: A23F 5/223 using flocculating, precipitating, adsorbing or complex-forming agents, or ion-exchangers
• CPC Class Codes: B01J 20/268 Polymers created by use of a template, e.g. molecularly imprinted polymers

Abstract

A method and product for decaffeinating an aqueous solution, such as a cup of coffee or tea, includes exposing the aqueous solution (that is to be decaffeinated) to a plurality of molecularly imprinted polymer beads (MIPS) that have receptor sites on the surfaces thereof that include imprints that match the physical shape of at least a portion of a caffeine molecule. A quantity of the caffeine molecules align with and adhere to some of the receptor sites and, accordingly, they are removed from the aqueous solution producing a decaffeinated aqueous solution. The MIPS are contained in an enclosure having a plurality of openings large enough to permit the aqueous solution to pass through and small enough so as to prevent the MIPS from passing through. Accordingly, the MIPS are absent from the decaffeinated aqueous solution. A variety of ways of affecting the efficacy of the process are described, such as varying the time the aqueous solution is exposed to the MIPS or varying the quantity of MIPS (beads) that the aqueous solution is exposed to. Processes useful for creating the MIPS and of removing the caffeine molecules therefrom (i.e., cleaning the MIPS so that they are suitable to use in decaffeinating the aqueous solution) are described. The cleaning and subsequent reuse of the MIPS is also described.

Claims

1. A process for decaffeinating an aqueous solution, such as a beverage that contains caffeine, which comprises:

contacting said aqueous solution with at least one molecularly imprinted polymer, said molecularly imprinted polymer having at least one site imprinted on a surface thereof that is adapted to cooperate with said caffeine by extracting at least one caffeine molecule from said aqueous solution.

2. A process for decaffeinating an aqueous solution, such as an extract of a vegetable material, which comprises:

contacting said aqueous solution with at least one molecularly imprinted polymer, said molecularly imprinted polymer having at least one site imprinted on a surface thereof that is adapted to cooperate with at least a portion of a caffeine molecule.

3. The process of claim 2 wherein the step of contacting said aqueous solution includes contacting said aqueous solution with at least one molecularly imprinted polymer, said molecularly imprinted polymer having at least one site imprinted on the surface thereof that is adapted to cooperate with at least a portion of a said caffeine molecule by extracting said caffeine molecule from said aqueous solution.

4. A process for decaffeinating an aqueous solution, such as an extract of a vegetable material, which comprises:

exposing said aqueous solution to at least one molecularly imprinted polymer, said molecularly imprinted polymer having at least one site on a surface thereof that is adapted to receive at least a portion of a caffeine molecule.

5. The process of claim 4 wherein the step of exposing includes exposing said aqueous solution to said molecularly imprinted polymer wherein said molecularly imprinted polymer includes means for retaining said caffeine molecule in proximity to said at least one site.

6. The process of claim 5 wherein said means for retaining includes non-covalent bonding.

7. The process of claim 5 wherein said means for retaining includes hydrogen bonding.

8. The process of claim 4 including the step of forming a plurality of molecularly imprinted polymer beads from said at least one molecularly imprinted polymer prior to the step of exposing said aqueous solution thereto.

9. The process of claim 8 wherein the step of forming includes grinding said at least one molecularly imprinted polymer.

10. The process of claim 8 wherein the step of forming includes pulverizing said at least one molecularly imprinted polymer.

11. The process of claim 8 wherein the step of forming includes fracturing said at least one molecularly imprinted polymer.

12. The process of claim 8 including the step of washing said plurality of molecularly imprinted polymer beads after the step of forming said plurality of molecularly imprinted polymer beads and prior to the step of exposing said aqueous solution thereto.

13. The process of claim 12 wherein the step of washing includes exposing said plurality of molecularly imprinted polymer beads to a cleaning solution.

14. The process of claim 13 wherein the step of washing includes exposing said plurality of molecularly imprinted polymer beads to a cleaning solution that contains a solvent.

15. The process of claim 13 wherein the step of washing includes exposing said plurality of molecularly imprinted polymer beads to a cleaning solution that contains an organic solvent.

16. The process of claim 8 including the step of removing at least a portion of caffeine molecules that were used to imprint said at least one molecularly imprinted polymer from the surface of said plurality of molecularly imprinted polymer beads after the step of forming said plurality of molecularly imprinted polymer beads and prior to the step of exposing said aqueous solution thereto.

17. The process of claim 12 including the step of drying said plurality of molecularly imprinted polymer beads after the step of washing said molecularly imprinted polymer beads and prior to the step of exposing said aqueous solution thereto.

18. The process of claim 12 including the step of reusing said plurality of molecularly imprinted polymer beads after the step of exposing said aqueous solution thereto.

19. The process of claim 18 wherein the step of reusing includes exposing a second aqueous solution to said molecularly imprinted polymer beads.

20. The process of claim 18 including the step of washing said molecularly imprinted beads after the step of exposing said aqueous solution thereto and before the step of exposing said second aqueous solution thereto.

21. The process of claim 8 including the step of exposing said plurality of molecularly imprinted beads to said aqueous solution.

22. The process of claim 4 including the step of imprinting said at least one site to correspond with at least a portion of the molecular shape of a caffeine molecule.

23. A process for simultaneously brewing and decaffeinating a beverage, such as coffee or tea, which comprises:

(a) forming a caffeinated aqueous extract; and

(b) exposing said caffeinated aqueous extract to a plurality of molecularly imprinted polymer beads, at least some of said molecularly imprinted polymer beads including at least one site on a surface thereof that is adapted to receive a caffeine molecule.

24. The process of claim 23 wherein the step of forming said caffeinated aqueous extract includes contacting a vegetable material with water.

25. The process of claim 24 wherein the step of forming said caffeinated aqueous extract includes the step of containing said vegetable material.

26. The process of claim 23 wherein the step of forming said caffeinated aqueous extract includes the step of containing said plurality of molecularly imprinted polymer beads in an predetermined area, said predetermined area adapted to facilitate the step of exposing said caffeinated aqueous extract to said plurality of molecularly imprinted polymer beads.

27. The process of claim 26 wherein the step of containing said plurality of molecularly imprinted polymer beads includes contacting said plurality of molecularly imprinted beads with said caffeinated aqueous extract to produce a decaffeinated aqueous extract.

28. The process of claim 27 including the step of collecting said decaffeinated aqueous extract.

29. The process of claim 26 wherein the step of containing said plurality of molecularly imprinted polymer beads includes placing said plurality of molecularly imprinted polymer beads in an enclosure.

30. The process of claim 23 wherein the step of forming said caffeinated aqueous extract includes adding water to a coffee.

31. The process of claim 30 including the step of grinding said coffee before the step of adding water thereto.