CA1123656A - Process for decaffeinating raw coffee - Google Patents
Process for decaffeinating raw coffeeInfo
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- CA1123656A CA1123656A CA346,074A CA346074A CA1123656A CA 1123656 A CA1123656 A CA 1123656A CA 346074 A CA346074 A CA 346074A CA 1123656 A CA1123656 A CA 1123656A
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- caffeine
- coffee
- adsorption agent
- adsorption
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Abstract
ABSTRACT OF THE DISCLOSURE
Caffeine is extracted from the raw coffee by means of an aqueous liquid and adsorbed from the latter on an adsorption agent such as activated charcoal. In order for the adsorption agent to absorb as little as possible of other substances that are extractable from the coffee, the agent is previously loaded with such other extractable substances or with substitute substances having a molec-ular structure and size similar to the latter, more partic-ularly with carbohydrates as exemplified by cane sugar. The aqueous extractant is preferably a caffeine-free coffee extract solution which substantially extracts only caffeine from the coffee. Other aqueous liquids may be employed, but generally require recombination with the coffee after the adsorption step.
Caffeine is extracted from the raw coffee by means of an aqueous liquid and adsorbed from the latter on an adsorption agent such as activated charcoal. In order for the adsorption agent to absorb as little as possible of other substances that are extractable from the coffee, the agent is previously loaded with such other extractable substances or with substitute substances having a molec-ular structure and size similar to the latter, more partic-ularly with carbohydrates as exemplified by cane sugar. The aqueous extractant is preferably a caffeine-free coffee extract solution which substantially extracts only caffeine from the coffee. Other aqueous liquids may be employed, but generally require recombination with the coffee after the adsorption step.
Description
3~S6 BACKGROI~ND OF THE INVENTION
Field of the Invention The present invention relates to a process for removing caffeine fronl raw coffee. More specifically, the present invention relates to a process wherein raw co~fee is contacted with an aqueous liquid to extract the caffeine therefrom and the resulting liquid is contacted with an adsorption-agent that has been pre-loaded with at least one substance present in and extractable fronl ~he coffee or with a substitute therefor having a corresponding molecular struc-10 ture and size.
Description of the Prior Art It is known in the art that caffeine may be removed fronl raw coffee by various techniques. However, such known techniques generally present substantial disadvantages which detract fronl their use. For exanlple, in practically all well-known processes for decaffeinating raw coffee used today, the coffee is extracted using organic solvents. A main disadvantage of this process resides in the fact that at least a trace of the solvent remains in the treated coffee.
, 20 This residuum may adversely affect the taste and/or aroma of`the brewed coffee product thereby decreasing its palat-ability.
In order to avoid the use of organic solvents, it is also known to extract the raw coffee with an aqueous liguid, to remove the caffeine fronl the extract solution by adsorption on an adsorption agent and subse~uently to conlbine .
. : , . . .
36~i6 the remaining extract substances with the coffee beans. The disadvantage of the well-known process~s of this type is that the adsorption agent, more particularly activated charcoal, adsorbs considerable quantities of other substances in the coffee besides the caffeine which thereby are lost and thus results in a product having a lower extract content.
The search has therefore continued for a process which will eEfectively remove caffeine fronl raw coffee with-out imparting an undesirable taste and/or aroma to the 10 final product or substantially lessen the extract content.
This invention is the result of that search.
SUMM~RY AND OBJECTS OF THE INVENTION
Accordingly, it is a general object of the present invention to provide a process which eliminates or substan-tially obviates the problems of the prior art.
It is a nlore specific object of the present inven-tion to provide a process for removing caffeine from raw coffee which does not adversely affect the quality of the final product.
It is another object of the present invention to provide a process for removing caffeine from raw coffee whereby other extractable substances in the coffee are substantially not lost.
These objects and advantages of the present inven-tion will become apparent from the following summary and description of the preferred embodiments of the present inven-tion.
3~56 In one aspect, the present invention provides a process for decaffeinating coffee whereby the caffeine is extracted from raw coffee by nleans of an aqueous liquid and is adsorbed from the resulting liquid extract by contact with an adsorption agent. The improvenlent of the process comprises loading the adsorption agent prior to its use for adsorbing caffeine with at least one other substance present in and extractable from the raw coffee or with a substitute for said extractable substance having a nlolecular structure and size 10 corresponding to said extractable substance whereby the adsorption of coffee extract substances other than caffeine is decreased.
In another aspect, the present invention provides a process for extracting caffeine fronl raw coffee with an aqueous liquid and adsorbing the caffeine from said aqueous liquid by contact with a solid adsorption agent. The process comprises loading an adsorbent with an extractable substance that is co-extractabIe from raw coffee with caffeine or a substitute for said extractable substance having a molecular 20 structure and size corresponding to said extractable substance and thereby forming a pre-loaded adsorption ayent, passing an aqueous liquid through an extraction zone containing a batch of raw coffee and then through at least one column containing said pre-loaded adsorption agent.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As stated above, the present invention relates to a process for removing caffeine from raw coffee by extracting ~2;3~56 caffeine from the raw coffee with an aqueous liquid and con-tacting the resulting extract with an adsorption agent that has been pre-loaded with at least one selected non-caffeine substance.
Pretreatment of the Adsorption Agent ~ n adsorption agent such as activated aluniina, silica gel or, preferably, activated charcoal, is charged with at least one coffee extract substance which is to be kept in the raw coffee to be decaffeinated or with a substi-10 tute substance having a similar molecular structure andmolecular size. This "pre-loading" enables the adsorption agent, when it is brought into contact with a coffee extract solution, to adsorb at n~ost a small additional amount of the coffee extract substance. In this regard, the pre-loading can be regulated such that prior to contacting the adsorp-tion agent with the coffee extract solution, there exists a substantial equilibriun~ between the concerned extract substance in solution and that contained on the adsorption agent. Accordingly, the selectivity of the adsorption agent 20 for caffeine is increased.
The selection of the pre-loading substances is generally deternlined by the availability of acceptable substances and prevailing economic conditions. ~ pre- -loading substance which consists o a complete caffeine-free coffee extract would indeed be ideal but can usually be obtained only at prohibitive cost. However, nunlerous sub-stances exist which substantially reduce the loss of desired extract substances while pernlitting caffeine adsorption.
More particularly, essential coffee extract substances which are adsorbed to a considerable degree by activated charcoal are various sugars and chlorogenic acid. In order to reduce the adsorption effect of activated charcoal for these sub-stances, it can be pre-loaded with sucrose and/or glucose and/or other carbohydrates. Additionally or instead of the latter, chlorogenic acid can also be usedl but is presently substantially nlore expensive than sucrose in the form of cane sugar. Other acceptable coffee extract substances or lO substitutes` therefor will be apparent to those of ordinary skill in the coffee art.
For the pre-loading, an aqueous solution of the pre-loading substances is brought into contact with the adsorption agent. More specifically, the solution having a pre-deternlined concentration of the pre-loading substance or substances is placed in a heatable tank, heated to a speci-fied tenlperature and then punlped through a colunm containing the adsorption a`gent in circulation from the tank. The concentration of the pre-loading substances in the solution 20 is regulated such that they are substantially equal to the concentrati~ns of the corresponding extract substances in the coffee extract solution. The temperature of the pre-loading solution can range from about 20C. to about 100C~
and pre~erably from about 70C. to about 90C. In a column containing about 500 kg. of activated charcoal and having a flow rate of fronl about 5 to about 25 m3/hr., preferabl~
from about 5 to about 10 nl3/hr., the pre-loading period generally requires from about 2 to about 10 hours, prefer-ably fronl about 6 to about 8 hours. The pre-loading may 3O occur without recirculating the pre-loading solution wherein the adsorption agent is allowed to remain with the solution in a container heated to the desixed temperaturP.
There is a further beneficial effect on the quality of the prepared decaffeinated co~fee with respect to its color, when the adsorption agent, particularly activated charcoal, is also pre-loaded with an acid. The acid can be added to the described solution of pre-loading substances or passed apart fronl the latter in a separate solution. Accept-able acids are those permitted for foodstuff treatnlent such as, for example, acetic acid, hydrochloric acid, formic acid, etc. Preferably, acids are used which are contained in 10 coffee in the natural state. The concentration of acid in the solution may vary fronl about 0.5% to about 3% by weight.
Subsequent to the acid treatment, the adsorption agent is rinsed with water.
Adsorption of the Ca~feine Green or raw coffee is extracted with water or an agueous liquid and caffeine is adsorbed from the liquid by means of the pre-loaded adsorption agent. Preferably, a batch of coffee is nlixed in an extractor with the extracting liquid and the aqueous extract solution is recirculated 20 through a filter and through one or several adsorption columns in the circuit until it is free of caffeine.
In order to obtain a high utilization of the adsorp-tion capacity of the adsorption agent, it is preferable to employ two or more adsorption columns. For each batch, the extract solution from the extractor is first passed through one or several adsorption columns which have been previously used and then passed through a column with fresh, pre-loaded adsorption agent. In addition, it is possible to arrange the ~.Z36~
columns in series in the circuit or switch them into the circuit individually ana sequentially in tinle. At the end of the adsorption of the caffeine from a batch of extract solution, the colunln which has been used the longest is rinsed, emptied, refilled with the adsorption agent and pre-loaded.
As the liquid for extracting the green or raw coffee, it is preferred to use a caffeine-free coffee extract solution whose concentrations of coffee content substances 10 are so high that the solution dissolves substantially only caffeine. This is achieved d~e to the presence of concen-trations of other extractable substances in the solution which are in equilibrium with the concentrations of the corresponding substances in the coffee beans. This equi-librium is further maintained since the pre-loaded adsorp-tion agent adsorbs substantially only caffeine from the solution. The beans treated in this way must only be sub-sequently dried prior to further treatment.
In another embodiment of the invention, water is 20 used as the extracting liquid. Suitably used is the rinse water which is derived from rinsing the adsorption column which has been in longest use in the adsorption of a preced-ing batch of extract solution. This rinse water is preferred since it contains a significant concentration of coffee extract residues. In this embodiment, there are also extract substances other than caffeine dissolved out which, after the adsorption of the caffeine, must again be combined with the beans. For this purpose, subsequent to the adsorption procedure, the beans are separated from the extract solution 3L~..Z3656 and dried by means of hot air or under vacuum to a moisture content ranging between 10 and 40% by weight. The extract solution is concentrated under a vacuum in a distiller until the ratio of filled coffee weight (kg.) to concentrated extract solution (liter) has reached a value between about 5:1 and about 5:4. The concentrated extract solution is then placed together with the dried beans at a temperature of between about 40C. and about lOO~C., preferably between about 60C. and 80C. and adsorbed by the beans. Subsequently, lO the beans are again dried to the desired moisture content.
Suitable conditions for the described extraction and adsorption of caffeine are as follows:
Flow rate of the process liquid in the circuit through extractor and adsorption colunln(s):
5-25 m3/hr.;
Temperature: 40-100C., preferably 70-90C.;
Duration: 6-12 hr.;
Ratio of process liquid quantity (water quantity) to coffee quantity: 1:1 to 5:1.
The described rinsing of the adsorption column in longest use can take place after every adsorption cycle as follows: rinsing one or more tin~es with water, to which acids of the type also used for pre-loading can be added if necessary. If available, the condensate from the described distillation of the extract solution may be used as the rinse water in lieu of or in addition to fresh water.
Preferably, the rinse water is pumped fronl a heated rinse water tank in the circuit and through the adsorption colunln taken out of operation. Rinse water teniperatures generally ~.Z3~
range from about 50C. to about 100C., flow rates fronl about 5 to about 25 nl3/hr. and rinse periods from about .5 to about 2 hours. The rinse water may be used afterward as the extracting liquid for the next batch as has been pre-viously described.
According to the present invention, a satisfactory roàstable caffeine-free raw coffee is obtained having a bright color and with a good cup quality. The coffee has an extract content of nlore than 22~ and a caffeine content of 10 less than 0.1~ (after roasting).
Example In a pre-loading tank with a 2500 liter capacityr 2000 liters of water, 50 kg. of cane sugar and 10 kg. of formic acid (99/100~) are niixed and heated to 80C. This solution is passed for a period of 10 hours in the circuit through an activated charcoal column having 500 kg. of activated charcoal. The rate of flow is 10 m3/hr. Follow-ing this, the solution is pumped back into the pre-loading tank. The activated charcoal is then rinsed with 1000 20 liters of cold fresh water.
In an extractor with a 9000 liter capacity, 2500 kg. of raw coffee and 7000 liters of water are mixed. The liquid or extract solution is pumped through a filter at 70C. and 15 m3/hr. in the circuit through the pre-loaded activated charcoal column. After eight hours, the extract solution is practically caffeine-free. The total aqueous extract solution is placed in a distiller and concentrated ~.Z3~i56 under a vacuunl to 1000 liters. ~he beans are dried by hot air to 30% moisture content. Subsequently, the concentrated extract solution and the dried beans are placed together in the extractor. The beans completely absorb the entire extract solution at 75C. within three hours. The beans are then dried by hot air to a moisture content of 10%.
The column taken out of operation is rinsed three times, each time using 2000 liters of condensate of the distillation or fresh water which additionally contains 2-4 10 kg. of formic acid (99/100%~. The column is rinsed at 90C.
each tinle for 90 n~inutes, using a rinsing tank-to-column-to-rinsing tank circuit. The rinsing water is collected and used as extracting water for the following batch.
The extract content and the coffee content of the untreated raw coffee and the treated caffeine-free raw coffee were measured each time after roasting according to the regulations of the Swiss foodstuffs law. The untreated coffee contains after roasting 28~ extract substances and 1.3~ caffeine. The same coffee, treated in accordance with 20 the present invention, contains after roasting 2305~ extract substances and 0.04~ caffeine.
- As may be seen fronl the above description and specific example, raw coffee that is treated in accordance with the present invention may be further processed to yield a product that contains substantially all of the originally present extract substances, but which is substantially caffeine free.
Although the invention has been described with preferred embodiments, it is to be understood that variations ~.236~i6 and modifications nlay be resorted to as will be apparent to those skilled in the art. For example, although the process . has been described on a batch basis, it may likewise be perfornled on a semi-continuous or continuous basis. These variations and modifications are to be considered within the ~: scope of the following claims.
.~,
Field of the Invention The present invention relates to a process for removing caffeine fronl raw coffee. More specifically, the present invention relates to a process wherein raw co~fee is contacted with an aqueous liquid to extract the caffeine therefrom and the resulting liquid is contacted with an adsorption-agent that has been pre-loaded with at least one substance present in and extractable fronl ~he coffee or with a substitute therefor having a corresponding molecular struc-10 ture and size.
Description of the Prior Art It is known in the art that caffeine may be removed fronl raw coffee by various techniques. However, such known techniques generally present substantial disadvantages which detract fronl their use. For exanlple, in practically all well-known processes for decaffeinating raw coffee used today, the coffee is extracted using organic solvents. A main disadvantage of this process resides in the fact that at least a trace of the solvent remains in the treated coffee.
, 20 This residuum may adversely affect the taste and/or aroma of`the brewed coffee product thereby decreasing its palat-ability.
In order to avoid the use of organic solvents, it is also known to extract the raw coffee with an aqueous liguid, to remove the caffeine fronl the extract solution by adsorption on an adsorption agent and subse~uently to conlbine .
. : , . . .
36~i6 the remaining extract substances with the coffee beans. The disadvantage of the well-known process~s of this type is that the adsorption agent, more particularly activated charcoal, adsorbs considerable quantities of other substances in the coffee besides the caffeine which thereby are lost and thus results in a product having a lower extract content.
The search has therefore continued for a process which will eEfectively remove caffeine fronl raw coffee with-out imparting an undesirable taste and/or aroma to the 10 final product or substantially lessen the extract content.
This invention is the result of that search.
SUMM~RY AND OBJECTS OF THE INVENTION
Accordingly, it is a general object of the present invention to provide a process which eliminates or substan-tially obviates the problems of the prior art.
It is a nlore specific object of the present inven-tion to provide a process for removing caffeine from raw coffee which does not adversely affect the quality of the final product.
It is another object of the present invention to provide a process for removing caffeine from raw coffee whereby other extractable substances in the coffee are substantially not lost.
These objects and advantages of the present inven-tion will become apparent from the following summary and description of the preferred embodiments of the present inven-tion.
3~56 In one aspect, the present invention provides a process for decaffeinating coffee whereby the caffeine is extracted from raw coffee by nleans of an aqueous liquid and is adsorbed from the resulting liquid extract by contact with an adsorption agent. The improvenlent of the process comprises loading the adsorption agent prior to its use for adsorbing caffeine with at least one other substance present in and extractable from the raw coffee or with a substitute for said extractable substance having a nlolecular structure and size 10 corresponding to said extractable substance whereby the adsorption of coffee extract substances other than caffeine is decreased.
In another aspect, the present invention provides a process for extracting caffeine fronl raw coffee with an aqueous liquid and adsorbing the caffeine from said aqueous liquid by contact with a solid adsorption agent. The process comprises loading an adsorbent with an extractable substance that is co-extractabIe from raw coffee with caffeine or a substitute for said extractable substance having a molecular 20 structure and size corresponding to said extractable substance and thereby forming a pre-loaded adsorption ayent, passing an aqueous liquid through an extraction zone containing a batch of raw coffee and then through at least one column containing said pre-loaded adsorption agent.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As stated above, the present invention relates to a process for removing caffeine from raw coffee by extracting ~2;3~56 caffeine from the raw coffee with an aqueous liquid and con-tacting the resulting extract with an adsorption agent that has been pre-loaded with at least one selected non-caffeine substance.
Pretreatment of the Adsorption Agent ~ n adsorption agent such as activated aluniina, silica gel or, preferably, activated charcoal, is charged with at least one coffee extract substance which is to be kept in the raw coffee to be decaffeinated or with a substi-10 tute substance having a similar molecular structure andmolecular size. This "pre-loading" enables the adsorption agent, when it is brought into contact with a coffee extract solution, to adsorb at n~ost a small additional amount of the coffee extract substance. In this regard, the pre-loading can be regulated such that prior to contacting the adsorp-tion agent with the coffee extract solution, there exists a substantial equilibriun~ between the concerned extract substance in solution and that contained on the adsorption agent. Accordingly, the selectivity of the adsorption agent 20 for caffeine is increased.
The selection of the pre-loading substances is generally deternlined by the availability of acceptable substances and prevailing economic conditions. ~ pre- -loading substance which consists o a complete caffeine-free coffee extract would indeed be ideal but can usually be obtained only at prohibitive cost. However, nunlerous sub-stances exist which substantially reduce the loss of desired extract substances while pernlitting caffeine adsorption.
More particularly, essential coffee extract substances which are adsorbed to a considerable degree by activated charcoal are various sugars and chlorogenic acid. In order to reduce the adsorption effect of activated charcoal for these sub-stances, it can be pre-loaded with sucrose and/or glucose and/or other carbohydrates. Additionally or instead of the latter, chlorogenic acid can also be usedl but is presently substantially nlore expensive than sucrose in the form of cane sugar. Other acceptable coffee extract substances or lO substitutes` therefor will be apparent to those of ordinary skill in the coffee art.
For the pre-loading, an aqueous solution of the pre-loading substances is brought into contact with the adsorption agent. More specifically, the solution having a pre-deternlined concentration of the pre-loading substance or substances is placed in a heatable tank, heated to a speci-fied tenlperature and then punlped through a colunm containing the adsorption a`gent in circulation from the tank. The concentration of the pre-loading substances in the solution 20 is regulated such that they are substantially equal to the concentrati~ns of the corresponding extract substances in the coffee extract solution. The temperature of the pre-loading solution can range from about 20C. to about 100C~
and pre~erably from about 70C. to about 90C. In a column containing about 500 kg. of activated charcoal and having a flow rate of fronl about 5 to about 25 m3/hr., preferabl~
from about 5 to about 10 nl3/hr., the pre-loading period generally requires from about 2 to about 10 hours, prefer-ably fronl about 6 to about 8 hours. The pre-loading may 3O occur without recirculating the pre-loading solution wherein the adsorption agent is allowed to remain with the solution in a container heated to the desixed temperaturP.
There is a further beneficial effect on the quality of the prepared decaffeinated co~fee with respect to its color, when the adsorption agent, particularly activated charcoal, is also pre-loaded with an acid. The acid can be added to the described solution of pre-loading substances or passed apart fronl the latter in a separate solution. Accept-able acids are those permitted for foodstuff treatnlent such as, for example, acetic acid, hydrochloric acid, formic acid, etc. Preferably, acids are used which are contained in 10 coffee in the natural state. The concentration of acid in the solution may vary fronl about 0.5% to about 3% by weight.
Subsequent to the acid treatment, the adsorption agent is rinsed with water.
Adsorption of the Ca~feine Green or raw coffee is extracted with water or an agueous liquid and caffeine is adsorbed from the liquid by means of the pre-loaded adsorption agent. Preferably, a batch of coffee is nlixed in an extractor with the extracting liquid and the aqueous extract solution is recirculated 20 through a filter and through one or several adsorption columns in the circuit until it is free of caffeine.
In order to obtain a high utilization of the adsorp-tion capacity of the adsorption agent, it is preferable to employ two or more adsorption columns. For each batch, the extract solution from the extractor is first passed through one or several adsorption columns which have been previously used and then passed through a column with fresh, pre-loaded adsorption agent. In addition, it is possible to arrange the ~.Z36~
columns in series in the circuit or switch them into the circuit individually ana sequentially in tinle. At the end of the adsorption of the caffeine from a batch of extract solution, the colunln which has been used the longest is rinsed, emptied, refilled with the adsorption agent and pre-loaded.
As the liquid for extracting the green or raw coffee, it is preferred to use a caffeine-free coffee extract solution whose concentrations of coffee content substances 10 are so high that the solution dissolves substantially only caffeine. This is achieved d~e to the presence of concen-trations of other extractable substances in the solution which are in equilibrium with the concentrations of the corresponding substances in the coffee beans. This equi-librium is further maintained since the pre-loaded adsorp-tion agent adsorbs substantially only caffeine from the solution. The beans treated in this way must only be sub-sequently dried prior to further treatment.
In another embodiment of the invention, water is 20 used as the extracting liquid. Suitably used is the rinse water which is derived from rinsing the adsorption column which has been in longest use in the adsorption of a preced-ing batch of extract solution. This rinse water is preferred since it contains a significant concentration of coffee extract residues. In this embodiment, there are also extract substances other than caffeine dissolved out which, after the adsorption of the caffeine, must again be combined with the beans. For this purpose, subsequent to the adsorption procedure, the beans are separated from the extract solution 3L~..Z3656 and dried by means of hot air or under vacuum to a moisture content ranging between 10 and 40% by weight. The extract solution is concentrated under a vacuum in a distiller until the ratio of filled coffee weight (kg.) to concentrated extract solution (liter) has reached a value between about 5:1 and about 5:4. The concentrated extract solution is then placed together with the dried beans at a temperature of between about 40C. and about lOO~C., preferably between about 60C. and 80C. and adsorbed by the beans. Subsequently, lO the beans are again dried to the desired moisture content.
Suitable conditions for the described extraction and adsorption of caffeine are as follows:
Flow rate of the process liquid in the circuit through extractor and adsorption colunln(s):
5-25 m3/hr.;
Temperature: 40-100C., preferably 70-90C.;
Duration: 6-12 hr.;
Ratio of process liquid quantity (water quantity) to coffee quantity: 1:1 to 5:1.
The described rinsing of the adsorption column in longest use can take place after every adsorption cycle as follows: rinsing one or more tin~es with water, to which acids of the type also used for pre-loading can be added if necessary. If available, the condensate from the described distillation of the extract solution may be used as the rinse water in lieu of or in addition to fresh water.
Preferably, the rinse water is pumped fronl a heated rinse water tank in the circuit and through the adsorption colunln taken out of operation. Rinse water teniperatures generally ~.Z3~
range from about 50C. to about 100C., flow rates fronl about 5 to about 25 nl3/hr. and rinse periods from about .5 to about 2 hours. The rinse water may be used afterward as the extracting liquid for the next batch as has been pre-viously described.
According to the present invention, a satisfactory roàstable caffeine-free raw coffee is obtained having a bright color and with a good cup quality. The coffee has an extract content of nlore than 22~ and a caffeine content of 10 less than 0.1~ (after roasting).
Example In a pre-loading tank with a 2500 liter capacityr 2000 liters of water, 50 kg. of cane sugar and 10 kg. of formic acid (99/100~) are niixed and heated to 80C. This solution is passed for a period of 10 hours in the circuit through an activated charcoal column having 500 kg. of activated charcoal. The rate of flow is 10 m3/hr. Follow-ing this, the solution is pumped back into the pre-loading tank. The activated charcoal is then rinsed with 1000 20 liters of cold fresh water.
In an extractor with a 9000 liter capacity, 2500 kg. of raw coffee and 7000 liters of water are mixed. The liquid or extract solution is pumped through a filter at 70C. and 15 m3/hr. in the circuit through the pre-loaded activated charcoal column. After eight hours, the extract solution is practically caffeine-free. The total aqueous extract solution is placed in a distiller and concentrated ~.Z3~i56 under a vacuunl to 1000 liters. ~he beans are dried by hot air to 30% moisture content. Subsequently, the concentrated extract solution and the dried beans are placed together in the extractor. The beans completely absorb the entire extract solution at 75C. within three hours. The beans are then dried by hot air to a moisture content of 10%.
The column taken out of operation is rinsed three times, each time using 2000 liters of condensate of the distillation or fresh water which additionally contains 2-4 10 kg. of formic acid (99/100%~. The column is rinsed at 90C.
each tinle for 90 n~inutes, using a rinsing tank-to-column-to-rinsing tank circuit. The rinsing water is collected and used as extracting water for the following batch.
The extract content and the coffee content of the untreated raw coffee and the treated caffeine-free raw coffee were measured each time after roasting according to the regulations of the Swiss foodstuffs law. The untreated coffee contains after roasting 28~ extract substances and 1.3~ caffeine. The same coffee, treated in accordance with 20 the present invention, contains after roasting 2305~ extract substances and 0.04~ caffeine.
- As may be seen fronl the above description and specific example, raw coffee that is treated in accordance with the present invention may be further processed to yield a product that contains substantially all of the originally present extract substances, but which is substantially caffeine free.
Although the invention has been described with preferred embodiments, it is to be understood that variations ~.236~i6 and modifications nlay be resorted to as will be apparent to those skilled in the art. For example, although the process . has been described on a batch basis, it may likewise be perfornled on a semi-continuous or continuous basis. These variations and modifications are to be considered within the ~: scope of the following claims.
.~,
Claims (13)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for decaffeinating coffee whereby the caffeine is extracted from raw coffee by means of an aqueous liquid and is adsorbed from the resulting liquid extract by contact with an adsorption agent, the improvement which comprises loading the adsorption agent prior to its use of adsorbing caffeine with at least one other substance present in and extractable from the raw coffee or with a substitute for said extractable substance having a molecular structure and size corresponding to said extractable sub-stance whereby the adsorption of coffee extract substances other than caffeine is decreased.
2. Process according to Claim 1, wherein the adsorption agent is loaded with at least one carbohydrate.
3. Process according to Claim 1, wherein the adsorption agent is loaded with sucrose and/or glucose.
4. Process according to one of Claims 1 to 3 wherein the quantity of said other extractable substances loaded onto the adsorption agent is selected such that upon the subsequent absorption of caffeine the concentration of said other extractable substances remain substantially unchanged in the aqueous liquid.
5. Process according to Claim 4, wherein the adsorption agent is additionally loaded with an acid before adsorbing caffeine.
6. Process according to Claim 1 wherein the adsorption agent is pre-loaded with at least one acid natur-ally contained in coffee.
7. Process according to Claim 1 wherein the adsorption agent is pre-loaded with at least one acid selected from the group consisting of acetic, formic and hydrochloric acids.
8. Process according to Claim 1 wherein the adsorption agent is brought into contact with an aqueous solution of the loading substance or substances prior to contact with the caffeine containing liquid extract.
9. A process for extracting caffeine from raw coffee with an aqueous liquid and adsorbing the caffeine from said aqueous liquid by control with a solid adsorption agent which process comprises pre-loading an adsorption agent with an extractable substance that is co-extracted from raw coffee with caffeine or a substitute for said extractable substance having a molecular structure and size corresponding to said extractable substance and thereby forming a pre-loaded adsorption agent, passing an aqueous liquid through an extraction zone containing a batch of raw coffee and then through at least one column containing said pre-loaded adsorption agent.
10. Process according to Claim 9, characterized in that at least two adsorption columns are repeatedly used in a way such that the liquid coming from the extraction zone flows through at least one column with adsorption agent which has been previously used for adsorbing caffeine and afterward through a column with fresh adsorption agent.
11. Process according to Claim 9 or 10, charac-terized in that after utilization, the adsorption column in longest use is rinsed with water, and the rinse water containing the extract residue is used afterward as part of the aqueous liquid for extracting a next batch of raw coffee.
12. Process according to Claim 11, characterized in that, after the extracting and adsorbing of the caffeine, the aqueous liquid is concentrated at reduced pressure in a distiller and afterward combined with the raw coffee which has been dried.
13. Process according to Claim 9, characterized in that a caffeine-free coffee extract solution is used as the aqueous liquid for extracting the caffeine and whose concentration of coffee extract substances is such that substantially no other extractable substances are dissolved out of the raw coffee.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA346,074A CA1123656A (en) | 1980-02-20 | 1980-02-20 | Process for decaffeinating raw coffee |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA346,074A CA1123656A (en) | 1980-02-20 | 1980-02-20 | Process for decaffeinating raw coffee |
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| Publication Number | Publication Date |
|---|---|
| CA1123656A true CA1123656A (en) | 1982-05-18 |
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|---|---|---|---|
| CA346,074A Expired CA1123656A (en) | 1980-02-20 | 1980-02-20 | Process for decaffeinating raw coffee |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4481223A (en) * | 1983-10-13 | 1984-11-06 | General Foods Corporation | Decaffeination with treated activated carbon |
| US4495211A (en) * | 1981-10-27 | 1985-01-22 | Douwe Egberts Koninklijke Tabaksfabriek Koffiebranderijen Theehandel N.V. | Process for the decaffeination of green coffee beans |
| US4885181A (en) * | 1986-05-30 | 1989-12-05 | Douwe Egberts Koninklijke Tabaksfabriek-Koffiebranderijen-Theehandel, N.V. | Process for decaffeinating green coffee |
-
1980
- 1980-02-20 CA CA346,074A patent/CA1123656A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4495211A (en) * | 1981-10-27 | 1985-01-22 | Douwe Egberts Koninklijke Tabaksfabriek Koffiebranderijen Theehandel N.V. | Process for the decaffeination of green coffee beans |
| US4481223A (en) * | 1983-10-13 | 1984-11-06 | General Foods Corporation | Decaffeination with treated activated carbon |
| US4885181A (en) * | 1986-05-30 | 1989-12-05 | Douwe Egberts Koninklijke Tabaksfabriek-Koffiebranderijen-Theehandel, N.V. | Process for decaffeinating green coffee |
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