DECAFFEINATION METHODS AND SYSTEMS

• US 20170202234A1
• Filed: 03/17/2015
• Published: 07/20/2017
• Est. Priority Date: 03/26/2014
• Status: Active Grant

• Current Assignee: Infré SA
• Original Assignee: The INFRE SA
• Inventors: Fischer, Norbert, Weber, Carlo
• Granted Patent: US 10,426,178 B2
• Time in Patent Office: Days
• CPC Class Codes: A23F 3/36 Reducing or removing alkaloid content; Preparations produced thereby; Extracts or infusions thereof
• CPC Class Codes: A23F 3/385 using flocculating, precipitating, adsorbing or complex-forming agents, or ion-exchangers

Abstract

Disclosed is a water based method for extracting caffeine from alkaloid containing substances, in particular tea leaves. The method can be performed without the use of artificial substances. The method allows the other soluble, non-caffeine components of alkaloid containing substances to be part of the decaffeinated product, in particular, components such as catechins and antioxidants. Advantageously, the caffeine extracted from the alkaloid containing substances is reversibly adsorbed to an adsorbent and high percentile of the caffeine can be recovered from the adsorbent.

Claims

1. A method for producing a decaffeinated tea product, such as decaffeinated tea leaves, comprising

(i) adding water having a temperature of less than 70 degrees Celsius to tea leaves to form an aqueous tea leaf mixture,

(ii) separating the tea leaves from said aqueous tea leaf mixture to obtain an aqueous extract and extracted tea leaves;

(iii) contacting the aqueous extract of (ii) with an active carbon adsorbent (ACA);

(iv) adsorbing caffeine in said extract reversibly to the ACA to obtain an aqueous decaffeinated tea extract (DTE),

(v) contacting the aqueous DTE with the extracted tea leaves of (ii) to form a further aqueous tea leaf mixture, optionally, repeating (ii) to (iv) 2 to 12 times, and

vi) drying the further aqueous tea leaf mixture to obtain the decaffeinated tea product.

2. The method of claim 1, wherein in (v), (ii) to (iv) is repeated 2 to 12 times.

3. The method of claim 1, wherein the time between adding the water or DTE to form the aqueous tea leaf mixture in (i) or the further aqueous tea leaf mixture in (v) and separating the extracted tea leaves in (ii) is more than 2 minutes, but less than 60 minutes.

4. The method of claim 1 further comprising adding a solvent to the ACA and desorbing said caffeine adsorbed thereto, and optionally reusing the ACA in contacting a further aqueous extract of (ii) with said ACA.

5. The method of claim 4, wherein the caffeine desorbed is recovered from the solvent and the solvent is optionally recirculated to said ACA.

6. The method of claim 5, wherein said caffeine is dried by evaporation the solvent.

7. The method of claim 4, wherein said solvent is an alcohol or an ester.

8. The method of claim 4, wherein more than 60%, 70%, 80%, 90%, 95% or 98% of the caffeine adsorbed is resorbed from said ACA and is dissolved in said solvent.

9. The method of claim 1, wherein the ACA is part of an adsorption column.

10. The method of claim 1, wherein the ACA comprises porous carbon particles, wherein more than 90% of said particles have a size range of 0.1 to 0.66 mm and a surface area of higher than 1300 m²/g.

11. The method of claim 10, wherein the ACA has an iodine number that is higher than 1350 mg/g.

12. The method of claim 1, wherein the ratio of the tea leaves to water in (i) is 1:

5 to 1;

10, including 1;

5 to 1;

9, and 1;

6 to 1;

8.

13. The method of claim 1, wherein the water or aqueous tea leaf mixture in (i) or the DTE of (v) is less than 60°

C. when mixed with said tea leaves or extracted tea leaves.

14. The method of claim 1, wherein said separating in (ii) is centrifugal separating.

15. The method of claim 14, wherein said centrifugal separating is performed in a continuous flow centrifuge or a solid-bowl centrifuge.

16. The method of claim 1, wherein the decaffeinated tea product is black tea or green tea (Camellia sinensis L.), or Mate tea (Ilex paraguariensis L.)

17. The method of claim 1, wherein at least 85%, 90% or 95% of the caffeine is removed from the tea leaves and/or the caffeine remaining in the decaffeinated tea product does not exceed 0.4%.

18. The method of claim 1, wherein the tea leaves in (i) comprise non-caffeine water soluble components and the decaffeinated tea product in (vi) comprises:

non-caffeine water soluble components and at least about 50%, 60%, 70%, 80% of the non-caffeine water soluble components of the tea leaves of (i).

19. The method of claim 18, wherein said non-caffeine water soluble components are tea polyphenols (“

antioxidants”

), amino acids, theaflavin or derivatives thereof, and/or thearubigine.

21. A decaffeinated tea product made from tea leaves according to claim 1 comprising less than 0.5%, preferably less than 0.4%, 0.3%, 0.2% or 0.1% of caffeine and at least 40%, 50%, 60%, 70%, 80% or 90% of tea catechins, theaflavin, including theaflavin derivatives such as theaflavin-3-gallate, tharubigine and/or polyphenols such as epicatechins of the tea leaves it is made from.

25. The method of claim 2, wherein in (v), (ii) to (iv) is repeated 4 to 10 times.

26. The method of claim 3, wherein the time between adding the water or DTE to form the aqueous tea leaf mixture in (i) or the further aqueous tea leaf mixture in (v) and separating the extracted tea leaves in (ii) is between 2 and 20 minutes.

27. The method of claim 7, wherein the alcohol is methanol or ethanol, or the ester is ethyl acetate.

28. The method of claim 10, wherein the carbon particles are round.

29. The method of claim 13, wherein the water or aqueous tea leaf mixture in (i) or the DTE of (v) is 5°

C. to 60°

C., including 15°

C. to 50°

C. or 15°

C. to 30°

C., when mixed with said tea leaves or extracted tea leaves.

30. The method of claim 15, wherein the continuous flow centrifuge or the solid-bowl centrifuge are a countercurrent centrifuge or a concurrent centrifuge.

31. The method of claim 17, wherein the caffeine remaining in the decaffeinated tea product does not exceed 0.3%, 0.2% or 0.1%.

32. The method of claim 18, wherein the decaffeinated tea product in (vi) comprises:

at least about 90% of the non-caffeine water soluble components of the tea leaves of (i).

33. The method of claim 19, wherein the tea polyphenols include up to 30% of catechins and/or epicatechins of a dry weight of the tea leaves, the amino acids include L-theanin, and the theaflavin derivatives include theaflavin-3-gallate.

20. (canceled)

22. Method for decaffeination of alkaloid containing substances, comprising:

providing an active carbon adsorbent comprising porous carbon particles, more than 90% of said particles having;

a size range of 0.1 to 0.66 mm,

a surface area of >

1300 m²/g and

an iodine number that is higher than 1350 mg/g.

23. A system for decaffeinating alkaloid containing substances comprising:

a continuous flow centrifuge or a solid-bowl centrifuge comprising an inlet and at least one fluid outlet and at least one solids outlet, and an adsorption column, wherein the adsorption column is functionally attached to one of said at least one fluid outlets and comprises an active carbon adsorbent comprising, preferably spherical or round, porous carbon particles, more than 90% of said particles having;

a size range of 0.1 to 0.66 mm,

a surface area of higher than 1300 m²/g, and

an iodine number that is higher than 1350 mg/g.

24. A kit for decaffeinating tea comprising:

in one container a carbon adsorbent comprising;

an adsorption column comprising;

porous carbon particles,

more than 90% of said particles having a size range of 0.1 to 0.66 mm,

a surface area of >

1300 m²/g, and

an iodine number that is higher than 1350 mg/g,

the adsorption column being configured to adsorb caffeine from alkaloid containing substances and,

in a second container, instructions of how to use the column in extracting alkaloid containing substances from the tea.