JPH0227945A - Removal of caffeine from coffee using caffeic acid - Google Patents

Abstract

PURPOSE: To remove caffeine from coffee without adversely affecting the coffee by bringing a caffeine-contg. liq. extract of coffee into contact with caffeic acid in the presence of water and separating the resultant caffeine-caffeic acid complex. CONSTITUTION: A caffeine-contg. liq. extract of coffee such as a liq. extract of raw or roasted coffee or supercritical or liq. phase wet CO2 kept in contact with raw or roasted coffee is brought into contact with caffeic acid in the presence of water so that the molar ratio between caffeic acid and caffeine is regulated to at least 1:1 to form a water-insoluble caffeine-caffeic acid complex. This complex is separated from the liq. extract, e.g. by centrifugal separation.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for removing caffeine.

The method involves contacting a coffee extract containing caffeine with caffeic acid in the presence of water to form an insoluble complex of caffeine and caffeic acid, and then separating the caffeine/caffeic acid complex from the coffee extract. It consists of the process of The caffeine-containing extract may be a solution of any solvent, aqueous or non-aqueous, in direct contact with raw or roasted coffee to extract the caffeine, and It may be a solution of any solvent, aqueous or non-aqueous, in contact with a solution of the solvent used.

[Prior Art and Problems to be Solved by the Invention] There are many prior art techniques for removing caffeine. Among the widely used methods is the so-called water decaffeination method disclosed in Berry et al., U.S. Pat. No. 2,309,092.
n technique). This method extracts a low-caffeine raw coffee extract from raw hydrated coffee beans using a multi-stage countercurrent extraction battery. As raw coffee is extracted through the battery, the amount of caffeine in the extract increases if it comes into contact with coffee beans that have had less caffeine removed. The caffeinated coffee extract leaving the final stage of the battery is treated to remove caffeine before being returned to the system.

The caffeine is removed from the raw coffee extract by contacting it with an organic solvent, typically a halogenated organic solvent such as methylene chloride.

Although water decaffeination methods can be widely applied, it is becoming more desirable to avoid the use of organic solvents in food processing.

There are other ways to remove caffeine, but none that don't cause withdrawal. For example, European Patent No. 0.008 dated May 19, 1982. (No. 98 discloses an activated carbon adsorbent containing sugar. Although no organic solvent is used in this method, the activated carbon adsorbent absorbs coffee soluble substances other than caffeine as well as caffeine. Because it is stored away, economic efficiency is considerably reduced.

U.S. Pat. No. 4,31 to Fushiani et al.
No. 5,036 discloses a method for complexing only the decaffeination of aqueous black tea extracts. In this method, the aqueous black tea extract is cooled to precipitate a cold water-insoluble complex of caffeine and the tannins originally present in the black tea. The advantage of this method is that the substances for complex formation are already present in the black tea and do not need to be added later. Although it is true that tannin/caffeine complexes are insoluble and precipitate, tannins are not present in coffee.

It is known that many of the compounds present in coffee are complexes of caffeine. For example, in the summer, Homan (Ir.
orIIIan), R. Viani [
Properties and conformation of the caffeine-chlorogenate complex in coffee (J, Food Sci, 37
(1972) 925-27) lists ten such caffeine complexes, including the well-studied water-soluble chlorogenic acid/caffeine complex. Compounds that form complexes are considered to be effective in removing caffeine if the complexes formed are insoluble in water.
No such compounds have ever been identified in coffee. Furthermore, it is believed that any complex-forming compounds present in the coffee must compete with the chlorogenic acid and/or be relatively strong in breaking up the chlorogenic acid/caffeine complex.

[Means to solve the problem] The present invention relates to a method for removing caffeine.

The method involves contacting a coffee extract containing caffeine with caffeic acid in the presence of water to form an insoluble complex of caffeine and caffeic acid, and then separating the caffeine/caffeic acid complex from the coffee extract. It consists of the process of The caffeine-containing extract may be a solution of any solvent, aqueous or non-aqueous, in direct contact with raw or roasted coffee to extract the caffeine, and It may be a solution of any solvent, aqueous or non-aqueous, in contact with a solution of the solvent used.

The present invention has been shown to remove caffeine from coffee with little adverse effect on the coffee.

Caffeic acid is yellow crystalline and begins to soften at about 195°C. Caffeic acid is only slightly soluble in water at temperatures below about 25°C, but freely dissolves in water at temperatures above about 80°C. Freely soluble in alcohol over a wide range of temperatures.

However, unexpectedly, caffeic acid/caffeine complexes are insoluble in aqueous solutions over a wide range of temperatures. It is reported that caffeic acid is contained in roasted and ground coffee at a concentration of 0.5% by weight, but in reality, only a small amount is contained in unprocessed coffee, and there is no comparison in roasted coffee. Although there are many targets, it still contains only a small amount. Specifically, roasted coffee beans or typical soluble coffee powder contain only a few hundred pp. The reason why there is a large amount of caffeic acid in roasted coffee is that caffeic acid is one of the substances produced by roasting chlorogenic acid, which is relatively abundant. Although the caffeic acid used in the present invention may be chemically synthesized, it can be obtained from roasted coffee or by acid decomposition of chlorogenic acid, which is a compound originally present in coffee. Most preferably, the caffeine is removed by

Caffeic acid is particularly suitable for complexes in which caffeic acid is insoluble, even though chlorogenic acid is present in large amounts in coffee and the association coefficient of the caffeic acid/caffeine complex is smaller than that of the chlorogenic acid/caffeine complex. This is to form a The Homan et al. reference cited above as part of the specification has an association coefficient of 18.9 for the chlorogenic acid/caffeine complex and 12.2 for the caffeic acid/caffeine complex.
It is reported that. Since the association coefficient is a measure of the relative strength of the complexes, it is clear that the caffeic acid added to the coffee is already present in the coffee, dissociating the lorogenic acid/caffeine complex and forming insoluble colloids. It is surprising that a caffeic acid/caffeine complex can be formed.
It is the right thing to do. Such a fact would not be expected from the reported association coefficients.

In the present invention, caffeic acid is used in the caffeine-containing extract in the presence of water to remove caffeine from the caffeine-containing extract. The caffeine-containing extract may be a solution in any solvent, soluble or insoluble, that is brought into direct contact with the raw or roasted coffee to remove the caffeine, and may also be used to remove the caffeine from the raw or roasted coffee. It may be a solution of any solvent, aqueous or non-aqueous, in contact with a solution of the solvent used.

An example of a method for decaffeinating coffee extracts describes a method for obtaining a caffeine-containing extract by contacting an extract of raw or roasted coffee to remove the caffeine from the coffee. No. 4,521,438 to Zcler et al., which is incorporated herein by reference.

A typical raw coffee extract contains 20 to 35 weight percent coffee soluble materials and 0.5 to 1.0 weight percent caffeine. The roasted coffee extract commonly used to make soluble coffee may be decaffeinated. Such roasted coffee extract contains 10 to 30% by weight of coffee soluble substances and 0.5% by weight of coffee soluble substances.
It usually contains between 5% and 5% caffeine by weight. This patent describes contacting a caffeine-containing extract with caffeic acid to form an insoluble, colloidal caffeic acid/caffeine complex. Caffeic acid/
Crystals of the insoluble complex of caffeine are formed and separated from the liquid to remove caffeine. A solution of caffeic acid is about 50
Preferably, the contact with a coffee extract containing caffeine is carried out at a temperature between 125°C and 125°C. The molar ratio of caffeic acid and caffeine is generally 1=1 or more and 3:1 or less, and 1.5:1.
It is preferable that To aid in the formation of crystals, the method further includes adding about 0% of the mixture of caffeic acid and coffee extract.
to about 50°C. An acid may also be added to the coffee extract to bring the pH below about 4.5, which promotes crystal formation. The crystalline complex may be separated from the coffee extract by methods such as filtration or centrifugation.

In other embodiments of the invention, the caffeine-containing extract may be supercritical or liquid-phase moist carbon dioxide in contact with raw or roasted coffee to remove caffeine. .

A method for contacting raw coffee with supercritical carbon dioxide is described by Zosel, incorporated herein by reference.
el), US Pat. No. 4,280,839. The patent states that in a temperature range of 40 to 80°C, in a pressure range of 120 to 180 atm,
The coffee is contacted with moist carbon dioxide in a pressure vessel for an hour. The wet critical carbon dioxide enters the pressure vessel and exits through the coffee, where the caffeine is removed before reinjecting the wet carbon dioxide into the vessel. In the present invention, caffeine may be removed from the wet supercritical carbon dioxide by adding caffeic acid to the wet carbon dioxide solution coming out of the coffee container. After the crystals have formed, they are separated from the liquid in the same manner as described above. The decaffeinated wet supercritical carbon dioxide is then returned to the coffee container.

In another embodiment of the invention, the caffeine in raw coffee beans may be removed using an ester solution of edible carboxylic acid and polyhydric alcohol. This method is described by Mitchell I, hereby incorporated by reference.
) et al., U.S. Pat. No. 3,682,848. The above-mentioned caffeine may be removed from the caffeine-containing extract by contacting it with caffeic acid in the presence of water to form and enlarge crystals. The crystals are then separated from the solution. The fully decaffeinated coffee extract may be re-infused into coffee for further decaffeination.

In addition to the caffeine-containing extracts mentioned above, caffeic acid may be used to remove caffeine from any aqueous or non-aqueous caffeine-containing extract that has come into contact with raw or roasted coffee. You can. Water must be present for complex formation when non-aqueous solutions are used. Water may be present in free form if the solvent is immiscible with water, or water may be dissolved in the solvent if the solvent is miscible with water.

In another embodiment of the invention, this solution is subjected to a second or subsequent process to remove the caffeine present in the extraction solvent obtained by contacting the extract with raw or roasted coffee. It may also be transferred into the extract. Caffeine must be removed from the next extract containing this caffeine.

One embodiment of the present invention is US Pat.
No. 547.378. According to this process,
The aqueous roasted coffee extract is freed from caffeine by contacting it with a halogenated hydrocarbon, such as methylene chloride, to transfer small amounts of caffeine and non-caffeine soluble substances from the roasted coffee extract to the caffeine solvent. Remove.

To separate a sufficiently decaffeinated roasted coffee extract from a caffeine-containing solvent. The caffeine solvent is then concentrated to at least 4% by weight. The concentrated solvent is then contacted with an aqueous suspension of caffeic acid containing at least equimolar amounts of caffeic acid to caffeine in the solvent. After a complex of caffeic acid and caffeine is formed in the aqueous phase, the crystals are separated by furnace. The aqueous phase is then separated from the caffeine solvent. The caffeine solvent, which still contains soluble substances other than caffeine, is added to the fully decaffeinated roasted coffee extract. The organic caffeine solvent is then removed from the roasted coffee and the coffee is dried to provide soluble coffee with improved flavor.

Another embodiment of the invention using a second extract containing caffeine is similar to the supercritical carbon dioxide system described above. However, in such embodiments, the caffeic acid does not come into contact with the stream of moist supercritical carbon dioxide as it exits the coffee container. The wet carbon dioxide is first contacted with another solvent, such as water, in a scrubber column using water to remove caffeine from the wet supercritical carbon dioxide. When water exits the scrubber, it comes into contact with caffeic acid and forms insoluble crystals, which are complexes of caffeine and caffeic acid. This crystal is removed by the method described above. The decaffeinated water is then recirculated to the scrubber. Very little coffee-flavored precursors are removed from the system because very little coffee-flavored precursors are transferred to the aqueous phase, but the aqueous phase that is passed back to the scrubber eventually becomes saturated with all the coffee-flavored precursors.

In other embodiments of the invention, the aqueous extract containing caffeine may contain caffeine which is removed from the extract by contacting the extract with a water-immiscible fat. An example of such a process is Pagliaro (Pag
U.S. Pat. No. 4,465,699 to llaro et al. According to this step, a caffeine-containing extract is brought into contact with a water-immiscible liquid fat capable of removing caffeine from the extract. Fats include saturated and unsaturated fats and oils such as coffee oil. The fat is contacted with the extract for a time sufficient for caffeine to migrate from the extract to the fat. The aqueous extract is then separated from the caffeine-containing fat. A suspension of caffeic acid in water is then contacted with the fat to transfer the caffeine to the aqueous phase. When caffeine enters the aqueous phase, it forms an insoluble crystal complex with caffeic acid and rapidly precipitates in solution. As caffeine is being removed from the system, more caffeine is transferred to the aqueous phase to maintain this phase partitioning equilibrium. This movement of caffeine continues until the desired degree of fatty caffeine has been removed. In this way, caffeine is removed from the oil as well as from the water. Water containing various coffee components can be added back into the extract stream and contacted with fresh coffee oil. Eventually, this aqueous phase becomes saturated with the desired components other than caffeine. Furthermore, although it does not prevent the removal of caffeine, it does not prevent the movement of solids other than caffeine.
Caffeine is removed from the aqueous phase and saturated with non-caffeine solids. Fats eventually become sufficiently cyclically processed that they become saturated with compounds other than caffeine.

In other embodiments of the invention, non-fatty, non-halogenated caffeine solvents may be used to remove caffeine from coffee extracts. Such solvents include ethyl acetate; benzyl alcohol; hydrocarbons such as non-aromatics such as xylene or liquid cycloalkanes; diethyl ether; hydrocarbons including aromatics such as xylene or non-aromatics such as liquid low-molecular alcohols; and acetone. etc. This method is described in Strobel et al., US Pat. No. 4,256,774. In this method, the coffee extract from which caffeine is to be removed may be contacted with a solvent such as ethyl acetate saturated with water, and the caffeine may be transferred to the solvent. Dry caffeic acid may be added to the solvent to form an insoluble caffein/caffeic acid complex and removed from the solvent. No aqueous phase is used in this step, but the water is dissolved in ethyl acetate.

The present invention will be further explained in the following examples, but the present invention is not limited to the scope detailed here.

Example 1 30.0 g water, 1.65 g chlorogenic acid and 0,
An equimolar aqueous solution of chlorogenic acid and caffeine was prepared by mixing 9 g of caffeine and heated until almost boiling. To this heated aqueous solution, 0.9 g of caffeic acid having an equimolar amount as chlorogenic acid and caffeine was added and dissolved. The solution was then allowed to cool to ambient temperature. Formation of crystals was observed after about 1 hour. After 12 to 14 hours, the crystals were separated from the solution using coarse paper. Subsequent analysis revealed that approximately 93% of caffeine was removed, but no removal of chlorogenic acid was detected.

Caffeine analysis in this example and the following examples was performed by measuring the removal of caffeine by the change in the area of the peak attributed to caffeine in high performance liquid chromatography (HPLC). Analytical columns (5μ
A spherical C18'3.9 am x 15 cm) was used.

The mobile phase consisted of 0.0033MKH2PO4, methanol and acetic acid 80:20:4. Analysis was performed at ambient temperature, flow rate 1.5ml/win, injection volume 5μ.
The same procedure was performed using g.

The solution was diluted with mobile phase to a total solids content of 0.1% by weight before analysis.

Example 2 An aqueous solution was prepared by dissolving 0.9 g of caffeic acid in 90 g of boiling water. Then to this solution 9.5% by weight
10 g of dry coffee extract containing caffeine was dissolved. A control sample was prepared by dissolving lO.Og of coffee in 90.0g of water. These two coffee solutions were allowed to cool. After 12 to 14 hours, crystals were observed in the solution containing caffeic acid. No crystals were observed in the control sample. After - weeks, further crystal formation was observed in the solution containing caffeic acid.

The weed solution was separated from the crystals by decantation and left to stand for another week. Analysis of a small amount of the solution revealed that it contained approximately 0% less caffeine than originally. No crystals were observed in the control sample. Even after the second week, crystal formation was observed again in the solution containing caffeic acid. When a small amount of the solution was analyzed, the caffeine content was approximately 5% from the beginning.
% was found to be less. Analysis of the crystals revealed that they were essentially a complex of caffeic acid and caffeine in a molar ratio of 1:1. No crystals were observed in the control sample, and analysis revealed that all of the caffeine that had been in the solution from the beginning remained intact.

Example 3 A 10% by weight coffee solution was prepared from dried coffee extract containing 8.7 fffffl% caffeine. This solution was divided into four portions and heated to 70°C.

The three solutions contain caffeic acid and caffeine in a molar ratio of 1.1.
Caffeic acid was added so that the ratio was 1:1.

The four samples were then cooled to 40°C. Acetic acid was added to two of the caffeic acid samples, one to pH 4.5 and the other to pH 4.2. Four samples were stirred at 40°C and analyzed at scheduled times. The results are shown in the table below.

Table 1 Caffeine reduction rate (%) Sample Acetic acid 1α JM sample - No caffeic acid) Not used 2
Not used 3
Use 4 After 5 days of use, samples 2.3 and 4 were ultracentrifuged at 350.0008's for 30 minutes to remove crystals. We went door to door. As a result of analysis, the crystals have a substantially molar ratio of caffeic acid to caffeine of 1.
:1 pure complex. Control sample (sample 1
) No crystals were observed at all.

Example 4 Using a multi-stage counter-current extraction battery consisting of 1.6 stages and using a water supply temperature of about 180°C, a roasted coffee extract containing about 15% by weight of total solids and 0.6% by weight of caffeine was obtained. Ta.

2. Add this roasted coffee extract to Centrisam (Ce
(ntrither II) Concentrate using an evaporator to remove aroma and flavor to a solid content of about 55%.

3. The coffee extract was diluted to a concentration of about 25% total solids and about 1% caffeine by weight.

4. Karr the coffee extract at ambient temperature.
) was contacted with methylene chloride in a column. The weight ratio of methylene chloride to coffee extract was 4.5+1. The caffeine content was more than 97% lower than the original amount. The methylene chloride coming out of the Karl column has a total of 0
．． It contained 25% by weight of soluble material. The concentration of caffeine was 0.17% by weight, and the remainder of the above 0.25% by weight was soluble substances other than caffeine.

5. The methylene chloride was concentrated in a distiller to a total solid content of 10.5% by weight and caffeine of 7.0% by weight.

6. A 250 cc sample of this methylene chloride was contacted in a beaker with 500 cc of an aqueous caffeic acid suspension containing 23 g of caffeic acid. The contact was carried out for 30 minutes at ambient temperature with gentle stirring. Crystal formation was observed at the boundary between water and methylene chloride.

7. The crystals were then separated from the liquid using coarse paper. The methylene chloride and water phases were left to separate and the water was removed by decantation.

Analysis of the crystals revealed that it was an equimolar complex of caffeic acid and caffeine. Analysis of the methylene chloride revealed that 90% of the caffeine originally present had been removed.

8. The aqueous phase recovered in step 7 was diluted with 55 ee of methylene chloride.
It was washed twice and soluble substances other than caffeine were collected. This methylene chloride wash step may be followed by treating the water used in the aqueous suspension.

9. 50 ecX 2 of methylene chloride from Step 8 was mixed with the above solvent. The solvent was distilled under reduced pressure at 32 to 35°C to give 110
It was set as cc.

10. A concentrated 1 LOcc sample of methylene chloride was contacted in a beaker with a LIOcc aqueous caffeic acid suspension containing 5 g of caffeic acid. An aqueous suspension was made using the water suspension in step 8. Contacting was carried out for 30 minutes at ambient temperature with gentle stirring. Crystal formation was again observed at the boundary between water and methylene chloride.

11. The components were separated again in the same manner as in step 7. It was found that an additional 70 weight percent of the caffeine present in methylene chloride was removed. Through this two-step caffeine removal operation, a total of about 97% by weight of caffeine was removed.

12. The methylene chloride from step 11 was added to the decaffeinated roasted coffee extract from step 4. Thereafter, methylene chloride was removed by vacuum distillation at an absolute pressure of about 0.5 atm and a temperature of 65°C.

13. The aqueous phases of steps 8 and 11 were added to the extract of step 12 and the extract was diluted to a normal strength coffee liquor with about 1% total solids by weight.

14. A control sample of roasted coffee extract decaffeinated with methylene chloride under the same conditions was prepared. However, caffeine was not subsequently removed from the methylene chloride or added back. This control sample was also diluted to about 1% total solids by weight.

15, Step 13 extracts and control samples were tested on an expert panel. The extract of step 13 was judged to be noticeably richer than the thin control sample.

Example 5 When 2Ω ethyl acetate was brought into contact with 75 cc of water and equilibrated for 1 hour, 86 cc of water was dissolved. After removing the remaining water, 35 g of caffeine was added to ethyl acetate saturated with water, and the mixture was allowed to stand for 18 hours. The solution was then filtered to remove remaining caffeine. Approximately 25 g of caffeine was dissolved, resulting in a solution containing 163% by weight of caffeine.

250 c of ethyl acetate saturated with this water and caffeine
2.52 g of caffeic acid was added to C to give 1.5 moles of caffeic acid per mole of caffeine. Caffeine/caffeic acid was observed to crystallize while the suspension was stirred for 3 hours. This indicates that the added caffeic acid forms a complex with caffeine. The mixture was allowed to stand for 1 hour and analyzed for caffeine, which revealed that the amount of caffeine was 67% less.

Example 6 500 cc of vegetable oil was contacted with 100 cc of water and 5 g of caffeine and stirred for 1 hour. The solution was then filtered to remove residual caffeine and separated from the aqueous phase. The water saturated vegetable oil was analyzed and found to contain 0.11% caffeine. 200 cc of this oil was contacted with 25 cc of water and 0.5 g of caffeic acid. The system was stirred for approximately 18 hours to reach equilibrium. A subsequent analysis of how much caffeine was removed from the oil revealed that 96% of the caffeine had been removed.

The solid content from the sample was separated in a furnace and observed under a microscope. Approximately half of the caffeic acid was found to be a caffeine complex with a different crystal structure.

Example 7 Caffeine was extracted from raw coffee beans by contacting them with supercritical carbon dioxide in an extraction column.

This supercritical carbon dioxide was scrubbed with water to remove caffeine. The water after scrubbing was an aqueous solution containing 0.3% polymerization of caffeine and had a pH of 2.6.

150 g of the aqueous solution was placed in a beaker. Caffeine dissolved in the sample is 0.45g. To this aqueous solution, 1.25 g of caffeic acid powder was added so that the molar ratio of caffeic acid to caffeine was 3=1. The sample was heated on a stir plate to bring it to a boil and dissolve the caffeic acid. Thereafter, when this solution was allowed to cool to room temperature, a caffeine-caffeic acid complex was precipitated together with excess caffeic acid crystals.

The next day, the amount of caffeine in the broth was analyzed using high-performance liquid chromatography, and it was found that the amount of caffeine had decreased by 92%. The control sample was 0.3 in pure water.
prepared under the same conditions using % caffeine. When the same procedure as above was performed, the amount of caffeine was reduced by 93%. This shows that solid substances other than caffeine have almost no effect on the efficiency of removing caffeine by the operation of this example.

Claims (1)

[Claims] 1. (a) Contacting a coffee extract containing caffeine with caffeic acid in the presence of water to form an insoluble caffeine/caffeic acid complex from caffeine and caffeic acid; (b) ) separating the caffeine/caffeic acid complex from the coffee extract; a method for removing caffeine comprising each step; 2. The method of claim 1, wherein the caffeine-containing extract is moist supercritical carbon dioxide. 3. The method of claim 2, wherein the caffeic acid is contacted with moist supercritical carbon dioxide at a temperature between about 50 and about 125°C. 4. The method of claim 2, wherein the caffeine-containing extract is a raw coffee extract. 5. The method of claim 2, wherein the caffeine-containing extract is a roasted coffee extract. 6. The molar ratio of caffeic acid and caffeine is at least 1
3. The method of claim 2, wherein the caffeic acid is combined with a coffee extract containing caffeine in an amount of 1:1. 7. The method according to claim 1, wherein the caffeine/caffeic acid complex is separated from the coffee extract by centrifugation. 8. The method of claim 1, wherein the caffeine-containing extract is an aqueous solution, and the aqueous solution contains the caffeine by prior contact with the moist supercritical carbon dioxide coffee extract. 9. The molar ratio of caffeic acid and caffeine is at least 1
9. The method of claim 8, wherein caffeic acid is combined with an aqueous solution containing caffeine in an amount of 1:1. 10. The method of claim 8, wherein the caffeic acid is contacted with the aqueous solution at a temperature between about 50 and about 125°C. 11. The method of claim 1, wherein the caffeine-containing extract is a non-halogenated caffeine solvent that contains caffeine by prior contact with the caffeine-containing extract. 12. The method of claim 11, wherein the pre-caffeine-containing extract is a raw coffee extract. 13. The method according to claim 11, wherein the extract containing caffeine in advance is an extract of roasted coffee. 14. The method of claim 11, wherein the non-halogenated caffeine solvent is fatty. 15. The method of claim 14, wherein the fat is a vegetable oil. 16. The method of claim 15, wherein the vegetable oil is coffee oil. 17. The method of claim 11, wherein the non-halogenated caffeine solvent is selected from the group consisting of aromatic and non-aromatic alcohols, esters, ethers and hydrocarbons. 18. The method of claim 17, wherein the non-halogenated caffeine solvent is an ester. 19. The method of claim 18, wherein the ester is ethyl acetate. 20. The method of claim 11, wherein the caffeic acid is combined with the non-halogenated caffeine-containing extract such that the molar ratio of caffeic acid to caffeine is at least 1:1. 21. The method of claim 11, wherein the caffeic acid is reacted with the non-halogenated caffeine-containing extract at a temperature below the boiling point of the caffeine solvent.