Claims
- 1. A method of treating green coffee beans comprising contacting green coffee beans with an aqueous solution of an organic acid which is insoluble in supercritical carbon dioxide, said organic acid being selected from the group consisting of tartaric acid, citric acid, malic acid, succinic acid, ascorbic acid, phenylacetic acid and oxalic acid, maintaining said green coffee beans in contact with said aqueous solution until a predetermined degree of acidification of said green coffee beans has occurred by absorption of said aqueous solution by said green coffee beans, said predetermined degree of acidification being that obtained which is equivalent to the use of a citric acid solution which has a citric acid concentration of between about 0.25% and about 3.0% by weight and the weight ratio of citric acid solution to green coffee beans is from about 1:3 to about 1:1 and decaffeinating said acidified green coffee beans by extraction with supercritical carbon dioxide.
- 2. A method according to claim 1, wherein said organic acid is citric acid.
- 3. A method according to claim 1, wherein said green coffee beans are maintained in contact with said aqueous acid solution until the moisture content of said green coffee beans is about 20% by weight.
- 4. A method according to claim 1, wherein said green coffee beans are maintained in contact with said aqueous acid solution until the moisture content of said green coffee beans is between about 20% and about 50% by weight.
- 5. A method according to claim 1, wherein said green coffee beans are maintained in contact with said aqueous acid solution until the moisture content of said green coffee beans is between about 30% and about 45% by weight.
- 6. A method according to claim 1, wherein said maintaining step comprises circulating said aqueous acid solution over said green coffee beans until said aqueous acid solution is substantially fully absorbed by said green coffee beans.
- 7. A method according to claim 1, wherein said maintaining step comprises circulating said aqueous acid solution over said green coffee beans until the acid concentration in said beans is substantially the same as that in said solution.
- 8. A method according to claim 1, wherein said green coffee beans are thereafter subjected to a roasting step.
- 9. A method according to claim 1, wherein said roast coffee beans are thereafter processed into a final coffee product.
- 10. A method according to claim 1, further comprising the step of contacting said green coffee beans with steam.
- 11. A method according to claim 10, wherein said steps of contacting with said aqueous solution and contacting with steam are performed simultaneously.
- 12. A method according to claim 10, wherein said contacting steps are performed by placing said green coffee beans in a vessel, introducing steam into said vessel through an inlet adjacent to the bottom of said vessel, and contacting said green coffee beans with a spray of said aqueous acid solution from a spray head adjacent to the top of said vessel.
- 13. A method according to claim 12, wherein said steps of contacting with an acidic fluid and contacting with steam are performed simultaneously.
- 14. A method according to claim 1, wherein said supercritical carbon dioxide comprises a mixture of carbon dioxide and water.
- 15. A method according to claim 1, wherein said supercritical carbon dioxide has a pressure in excess of about 200 bar.
- 16. A method according to claim 1, wherein said supercritical carbon dioxide has a pressure in excess of 240 bar.
- 17. A method according to claim 1, wherein said supercritical carbon dioxide has a pressure between about 250 bar and 310 bar.
- 18. A method according to claim 1, wherein said supercritical carbon dioxide has a temperature between about 60.degree. C. and about 120.degree. C.
- 19. A method according to claim 1, wherein said supercritical carbon dioxide has a temperature between about 70.degree. C. and about 110.degree. C.
- 20. A method according to claim 1, wherein said extracting step is performed with a weight ratio of supercritical carbon dioxide to green coffee beans of between about 50:1 and about 300:1.
- 21. A method according to claim 20, wherein said weight ratio is between about 75:1 and about 275:1.
REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 799,904 filed Nov. 26, 1992, now abandoned, which is a continuation of application Ser. No. 571,749 filed Aug. 23, 1990, now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0158381 |
Oct 1985 |
EPX |
247039 |
Feb 1926 |
GBX |
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Non-Patent Literature Citations (2)
Entry |
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Sivetz et al., Coffee Technology, 1979, Aui: Westport, Connecticut, pp. 582-584, 604. |
Continuations (1)
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Date |
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Parent |
571749 |
Aug 1990 |
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Continuation in Parts (1)
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Number |
Date |
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799904 |
Nov 1992 |
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