CA1248812A - Process for the production of decaffeinated tea - Google Patents
Process for the production of decaffeinated teaInfo
- Publication number
- CA1248812A CA1248812A CA000480013A CA480013A CA1248812A CA 1248812 A CA1248812 A CA 1248812A CA 000480013 A CA000480013 A CA 000480013A CA 480013 A CA480013 A CA 480013A CA 1248812 A CA1248812 A CA 1248812A
- Authority
- CA
- Canada
- Prior art keywords
- carbon dioxide
- tea
- extraction
- caffein
- process according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D11/00—Solvent extraction
- B01D11/02—Solvent extraction of solids
- B01D11/0203—Solvent extraction of solids with a supercritical fluid
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F3/00—Tea; Tea substitutes; Preparations thereof
- A23F3/36—Reducing or removing alkaloid content; Preparations produced thereby; Extracts or infusions thereof
- A23F3/366—Reducing or removing alkaloid content; Preparations produced thereby; Extracts or infusions thereof by extraction of the leaves with selective solvents
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Tea And Coffee (AREA)
- Extraction Or Liquid Replacement (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT
Process for the production of decaffeinated tea The present invention provides a process for the production of decaffeinated tea by extraction with carbon dioxide, which is supercritical with regard to pressure and temperature, in the presence of water, wherein a tea which has been adjusted to a water content of 15 to 50% by weight is first extracted at 50 to 70°C. with moist carbon dioxide at a pressure of from 260 to 350 bar, the caffein is then removed from the caffein-containing carbon dioxide in the same pressure range with active char-coal and thereafter the caffein-free carbon dioxide is recycled over the already extracted tea and the tea is separated from the carbon dioxide and dried.
The present invention also provides a device for carrying out this process.
Process for the production of decaffeinated tea The present invention provides a process for the production of decaffeinated tea by extraction with carbon dioxide, which is supercritical with regard to pressure and temperature, in the presence of water, wherein a tea which has been adjusted to a water content of 15 to 50% by weight is first extracted at 50 to 70°C. with moist carbon dioxide at a pressure of from 260 to 350 bar, the caffein is then removed from the caffein-containing carbon dioxide in the same pressure range with active char-coal and thereafter the caffein-free carbon dioxide is recycled over the already extracted tea and the tea is separated from the carbon dioxide and dried.
The present invention also provides a device for carrying out this process.
Description
The presen~ invention is concerned with a process for the production of decaffeinated tea.
Various methods are already known for decaffein-ating tea. Whereas in the case of decaffeinaking S coffee, raw beans can be used as starting material, in the case of decaffeinating tea it is necessary to start from a fermented product which, with regard to the aroma, i5 very critical and, in the case of the removal of the caffein, is, as a rule, very considerably impaired.
Thus, various processes are known for decaffein-ating with the use of organic sclvents, all of which have, however, the disadvantage that considerable parts of the aroma are also removed and a complete removal of the solvent from the tea is difficult.
Federal Republic of Germany Patent Specification No. 21 27 642 describes a process for decaffeinating tea in which, in a first process step, the aroma materials are removed from the dried tea with dry, supercriti~al carbon dioxide, subsequently, in a second step, the caffein is selectively extracted with moist supercritical carbon dioxide and, after again drying the tea, the aroma separated in the first extraction step is reimpregnated~ The extraction is thereby to be carried out at 40 to 60 C. in order not to impair the aroma and only after removal of the aroma is a hi~her temperature used. The caffein extraction is .
: . :
;
.
to be carried out at 200 to 250 bar. Separation of the caffein from the carbon dioxide then takes place by lowering the temperature and the pressure below the critical region.
An important disadvantage of this process is the fact that the aroma must first be e~tracted under conditions which are a~ mild as possible before the caffein can be extracted in a separate step under somewhat more severe conditions. A further dis-advantage of this process is the necessity of the two-stage rnethod of operation. Finally, the separ-ation of the caffein by decompression and lowering of the temperature is also laborious ~ince subsequently considerable energy must be expended in order again to bring the carbon dioxide into the supercritical range.
According to Federal Republic of Germany Patent Specification No. 26 37 197, an attempt has been made to overcome this latter disadvantage by removing the caffein from the carbon dioxide in the supercritical range by means of ion exchangers. Ho~ever, the known two-step extraction of the tea is retained unchanged, the conditions used being 40 C. and 200 bar.
It is an object of the present invention to provide a substantially simpler one-step process for the production of decaffeinated tea which selectively only extracts the caffein without co-extracting the aroma materials and also does not require any change between supercritical an~ undercritical temperature and pressurè conditions when using carbon dioxide as the extraction agent.
Thus, according to the present invention, there is provided a process for the production of decaffein-ated tea by extraction with carbon dioxide, which is supercritical with regard to pressure and temperature, in the presence of water, wherein a tea which has been adjusted to a water content of 15 to 5~/O by weight is first extracted in one step with moist carbon dioxide at a pressure of from 260 to 350 bar and at a temper-ature of from 50 to 70C., preferably of from 60 to 70C., the caffein is then removed from the caffein-containing carbon dioxide with active charcoal in the given pressure range and the so obtained caffein-free carbon dioxide is recycled over the decaffeinated tea and the latter is removed and dried.
The present invention is based upon the surpris-ing recognition that, under the above-given pressure and temperature conditions, in the case of the mainten-ance of a definite moisture content in the tea, it is possible selectively to extract practically only the caffein and thus the separate extraction of the aroma materials and the reimpregnation of the decaffeinated tea therewith is superfluous. It is thereby surpris-ing that, in spite of the high temperature employed, practically no substantial change of the sensitive , aroma materials is brought about and the tea sub-stantially retains its natural flavour and its natural aroma. There~ore, on the ~asis of this selective extraction, it is also possible, instead of ion exchangers, to use cheap active charcoal for the removal of the extracted caffein from the carbon dioxide although, in Federal Republic of Germany Patent Specification No. 26 37 197, the use of active charcoal is advised against because of its insufficient selectivity.
For the process according to the present invention, as a rule, dry tea is used which has previously been adjusted to the given moisture content of from 15 to 500/O by weight by the addition of water.
The adjustment of the moisture content can be achieved quite simply by the addition of the particularly necessary amount of water to the dry tea in an approp-riate mixing device and mixing for the uniform distribution of the moisture. The tea is preferably ad]usted to a content of 25 to 40% by weight of water, the best results being obtained with 28 to 35/~ by weight of water.
~s mentioned above, the carbon dioxide is used under supercritical conditions in a moist state. ~s 25 mentioned, the pressure must be from 260 to 350 bar and preferably from 260 to 300 bar, it being espec-ially preferred to use a pressure of from 270 ~o .
290 bar. The given temperature range of 50 to 70 C.
is critical. If the lower limit of 50C~ is gone below, the amount of caffein extracted ~rop~ drastic-ally and the process then operates substantially less economically and requires considerably longer extraction times. In the case of exceeding the upper limit of 70C., undesired changes in the aroma occur.
The amount of carbon dioxide to be used depends upon the amount of caffein to be extracted from the tea. Since, under the given pressure and temperature conditions, about 0.2 g. of caffein can be removed per kg. o~ carbon dioxide, it is preferable to use about
Various methods are already known for decaffein-ating tea. Whereas in the case of decaffeinaking S coffee, raw beans can be used as starting material, in the case of decaffeinating tea it is necessary to start from a fermented product which, with regard to the aroma, i5 very critical and, in the case of the removal of the caffein, is, as a rule, very considerably impaired.
Thus, various processes are known for decaffein-ating with the use of organic sclvents, all of which have, however, the disadvantage that considerable parts of the aroma are also removed and a complete removal of the solvent from the tea is difficult.
Federal Republic of Germany Patent Specification No. 21 27 642 describes a process for decaffeinating tea in which, in a first process step, the aroma materials are removed from the dried tea with dry, supercriti~al carbon dioxide, subsequently, in a second step, the caffein is selectively extracted with moist supercritical carbon dioxide and, after again drying the tea, the aroma separated in the first extraction step is reimpregnated~ The extraction is thereby to be carried out at 40 to 60 C. in order not to impair the aroma and only after removal of the aroma is a hi~her temperature used. The caffein extraction is .
: . :
;
.
to be carried out at 200 to 250 bar. Separation of the caffein from the carbon dioxide then takes place by lowering the temperature and the pressure below the critical region.
An important disadvantage of this process is the fact that the aroma must first be e~tracted under conditions which are a~ mild as possible before the caffein can be extracted in a separate step under somewhat more severe conditions. A further dis-advantage of this process is the necessity of the two-stage rnethod of operation. Finally, the separ-ation of the caffein by decompression and lowering of the temperature is also laborious ~ince subsequently considerable energy must be expended in order again to bring the carbon dioxide into the supercritical range.
According to Federal Republic of Germany Patent Specification No. 26 37 197, an attempt has been made to overcome this latter disadvantage by removing the caffein from the carbon dioxide in the supercritical range by means of ion exchangers. Ho~ever, the known two-step extraction of the tea is retained unchanged, the conditions used being 40 C. and 200 bar.
It is an object of the present invention to provide a substantially simpler one-step process for the production of decaffeinated tea which selectively only extracts the caffein without co-extracting the aroma materials and also does not require any change between supercritical an~ undercritical temperature and pressurè conditions when using carbon dioxide as the extraction agent.
Thus, according to the present invention, there is provided a process for the production of decaffein-ated tea by extraction with carbon dioxide, which is supercritical with regard to pressure and temperature, in the presence of water, wherein a tea which has been adjusted to a water content of 15 to 5~/O by weight is first extracted in one step with moist carbon dioxide at a pressure of from 260 to 350 bar and at a temper-ature of from 50 to 70C., preferably of from 60 to 70C., the caffein is then removed from the caffein-containing carbon dioxide with active charcoal in the given pressure range and the so obtained caffein-free carbon dioxide is recycled over the decaffeinated tea and the latter is removed and dried.
The present invention is based upon the surpris-ing recognition that, under the above-given pressure and temperature conditions, in the case of the mainten-ance of a definite moisture content in the tea, it is possible selectively to extract practically only the caffein and thus the separate extraction of the aroma materials and the reimpregnation of the decaffeinated tea therewith is superfluous. It is thereby surpris-ing that, in spite of the high temperature employed, practically no substantial change of the sensitive , aroma materials is brought about and the tea sub-stantially retains its natural flavour and its natural aroma. There~ore, on the ~asis of this selective extraction, it is also possible, instead of ion exchangers, to use cheap active charcoal for the removal of the extracted caffein from the carbon dioxide although, in Federal Republic of Germany Patent Specification No. 26 37 197, the use of active charcoal is advised against because of its insufficient selectivity.
For the process according to the present invention, as a rule, dry tea is used which has previously been adjusted to the given moisture content of from 15 to 500/O by weight by the addition of water.
The adjustment of the moisture content can be achieved quite simply by the addition of the particularly necessary amount of water to the dry tea in an approp-riate mixing device and mixing for the uniform distribution of the moisture. The tea is preferably ad]usted to a content of 25 to 40% by weight of water, the best results being obtained with 28 to 35/~ by weight of water.
~s mentioned above, the carbon dioxide is used under supercritical conditions in a moist state. ~s 25 mentioned, the pressure must be from 260 to 350 bar and preferably from 260 to 300 bar, it being espec-ially preferred to use a pressure of from 270 ~o .
290 bar. The given temperature range of 50 to 70 C.
is critical. If the lower limit of 50C~ is gone below, the amount of caffein extracted ~rop~ drastic-ally and the process then operates substantially less economically and requires considerably longer extraction times. In the case of exceeding the upper limit of 70C., undesired changes in the aroma occur.
The amount of carbon dioxide to be used depends upon the amount of caffein to be extracted from the tea. Since, under the given pressure and temperature conditions, about 0.2 g. of caffein can be removed per kg. o~ carbon dioxide, it is preferable to use about
2 to 20 kg. and more preferably about 3 to 10 kg. of carbon dioxide per gram of caffein to be extracted from the tea.
After the extraction, which generally lasts from about 2 to 10 hours, the carbon dioxide loaded with caffein is passed, while maintaining the pressure and temperature conditions in the given range, into contact with active charcoal, preferably in the form of an active charcoal packing, the caffein thereby passing into the active charcoal. Subsequently, the decaffeinated carbon dioxide is again recycled under the extraction pressure to the already extracted tea and thereby again passes thereto about the same amount of moisture w~ich was previously removed by the extraction. The process is preferably carried out 8~'~
with the use of several extraction autoclaves which can be connected in series or in parallel and which can be removed individually from the process cycle.
After ending of the recycling, there is thus obtained a moist tea with a greatly reduced caffein content and a practically unchanged aroma material content.
~his tea is then dried, preferably at a temperature o from 60 to 80C., and can then be used directly.
In the case of the adsorption of the caffein on to the actlve charcoal, a temperature of from 50 ; to 70C. is preferably maintained. The recycling of the carbon dioxide to the already extrac-ted tea, with ; remoistening thereof, preferably takes place in a temperature range of from 50 to 70C. and more preferably of from 60 to 70C.
The caffein-containing active charcoal can be extracted with a solvent, the caffein separated from aroma substances by salt formation and the aroma substances again added to the extracted tea.
~he extraction of the tea can be carried out ~ in a conventional autoclave which is filled with tea ; and through which carbon dioxide then flow~ in the longitudinal axis. Such an extraction autoclave preferably has a cylindrical shape and can typically 25 have a length to diameter ratio of about 3:1 to 8:1.
Such extraction autoclaves are of simple construction and can easily be supplied with material to be , ~8~
extracted by means of a removable lid.
~ 2 have found that in the case of an extraction autoclave constructed in this manner, an undesired solidification of the filling material frequently occurs. The reason for this is that, in the case of tea, as well as also in the case of most other natural materials, because of their particulate form, a high degree of cohesivity is present. In addition, process parameters, such as the degree of moisture, the carbon dioxide volume flow~ the rate of compress-ing and the changing velocities of the volume stream~
also bring about a tendency to solidification.
In the case of commencement of a solidification of the loosely packed material, the loss of pressure during the flowthrough of the packing increases, which results in a further solidification. The result of thi~ is a canal formation which, in turn, brings about inhomogeneities of the degree of extract-ion referred to the cross-section and height of the autoclave. This can result in a considerable pro-longation of the necessary extraction time~.
According to a preferred embodiment of the present invention, these disadvantages can be overcome by arranging the material to be extracted, namely tea, i ` 25 in the form of a hollow cylinder, the extraction being carried out concentrically by introducing unloaded carbon dioxide from a cylindrical surface, the loaded .
carbon dioxide collecting behin~ the other cylindrical surface and being passed from there to the active charcoal. The introduction of the carbon dioxide thereby takes place especially preferably from the outer cylindrical surface. In the case of an approp-riate shaping of the hollow cylinder, ther~ is hereby also provided the possibility of arranging the active charcoal in the inner space of the hollow cylinder, especially favourable flow conditions thereby being provided.
According to this preferred radial flow method, the flowed-through cross-section changes continuously on the path from one surface of the hollow cylinder to the other surface thereof in which direction the flowthrough must take place. In the case of the especially preferred embodiment with flowthrough from the outside to the inside, in comparison with the usual axial flowthrough of a cylindrically shaped extraction autoclave, the packed material mantle surface impinged against is 15 to 20 times greater, at the end upon reaching the internal hollow chamber about five times greater, depending upon the diameter of the inner hollow chamber. Correspondingly low are also the empty tube as well as the canal velocities between neighbouring particles. In the case of unchanged average residence time within the autoclave, the period of contact on an individually considered - 9- ~2:~8~2 particle is considerably increased.
The mechanical stressing of the packing is also considerably reduced in the case o~ this embodiment.
The pressure loss depends, as is known, quadratically upon the empty tube velocity and is directly proport-ional to the running pat~ of the fluid. Therefore, in the case of the radial flow method of extraction, the running path of the carbon dioxide is only about one tenth of the running path in the case of axial 10wthrough of the autoclave. Pressings of the pack-ing material are, therefore, avoided.
The especially preferred embodiment of the ; extraction with radial flowing in the case of the introduction of the extraction fluid from the oute-r cylindrical mantle has, in addition, the advantage that, in the hollow inner chamber of the hollow cylinder, there can be provided the active charcoal, In this way, pressure losses in pipes between extraction autoclaves and separation autoclaves are avoided and an especially advantageous mode of operation is possible.
The invention is illustrated in particular and pref ~ ed I e~bodiments ky reference to the accompanying drawings in which:
i Fig. 1 is a schematic illustration of a device accord~ to the present invPntion, which is explained in more detail in the Example; an~
:. ' ;
Fig. 2 is an illus~ation of an ~traction autoclave with raaial flow~ough ~ccord~g to the prese~t invention.
A device according to the present invention f~r carrying out the radial extraction process, such as is illustrated, for example in Fig. 2 of the accompany-ing drawings, comprises a cylindrical autoclave 1, an extraction agent inlet 2, a lid 3 and an extraction agent removal means 4 and has a cylindrical extraction material container 5, placed in the autoclave, with a perforated mantle 6 and a per~orated extraction agent collecting cylinder 7, arranged in the cylinder axis, which is in flow connection with the extraction agent removal means 4. The perforated extraction agent collecting cylinder 7 can have a tubular shape. This is especially preferred when the extraction fluid is to be collected and passed directly from the extraction autoclave via the extraction agent removal means 4 to a separate separation autoclave with active charcoal filling~
However, according to a special embodiment of the device according to the present invention, the extraction agent collecting cylinder 7 has an active charcoal filling, a separate separation autoclave thereby being rendered superfluous. '~he extraction material container 5 can have an annular-shaped lid 8 through which extends the extraction agent collection cylinder 8.
.
., :
:
' In the case of the device according to the present invention, there is obtained a uniform flow over the packing to be extracted.
~he container 5 for the material to be extracted S can be arranged fixedly in the autoclave 1 or can be removable therefrom. Depending thereon, the supply-ing with the material to be extracted takes place into the cylinarical autoclave or also after removal of the container for the material to be extracted.
The extraction agent collection cylinder 7 is prefer-ably constructed in such a manner that, in the case of filling with the packing material, it can be removed from the device ~his simplifies the empty-ing of the packing material. Before renewed filling, the pipe is then again inserted. However, the collection cylinder can also be fixedly installed.
The embodiment of the process and of the device according to the present invention with radial flow-through of the material to be extracted can, in principle, be used for any kind of packing materials which are to be subjected to a high pressure extraction with an extraction agent, such a9 carbon dioxide.
The following Example is given for the purpose of illustrating the present invention, reference thereby being made to the accompanying drawings~
Exam~le.
10 kg. of a Ceylon blend type of tea containing 5.9% by weight of water and 3.3% by weight of caffein are moistened with 3.5 litres of water in a mixing apparatus and subsequently placed in an extraction autoclave (E). Adsorber (A) is provided with 7 kg.
active charcoal. The extraction autoclave and the adsorber are brought to a pressure of 200 bar with carbon dioxide from a liquid storage vessel (V~ with the help of a pump Pl, whereafter the pump is taken out of the circulation. After switching on pump P2, carbon dioxide is circulated via the extraction autoclave and the adsorber, the temperature in the èxtraction autoclave thereby being increased to 63C.
by heat exchanger Wl. The pressure in the extraction autoclave is 290 bar. The adsorber is operated at a pressure of 280 bar and at a temperature of 61 C.
After ~.5 hours, the extraction is discontinued, the carbon dioxide in the extraction autoclave is let off up to pressure equalisation in the carbon dioxide storage vessel and thereafter released into the atmosphere. The tea is removed from the extraction autoclave and dried in a drier at 70C~ The extracted tea thus obtained has a residual moisture content of 4.5% by weight of water and a caffein content of 0.08% by weight.
After the extraction, which generally lasts from about 2 to 10 hours, the carbon dioxide loaded with caffein is passed, while maintaining the pressure and temperature conditions in the given range, into contact with active charcoal, preferably in the form of an active charcoal packing, the caffein thereby passing into the active charcoal. Subsequently, the decaffeinated carbon dioxide is again recycled under the extraction pressure to the already extracted tea and thereby again passes thereto about the same amount of moisture w~ich was previously removed by the extraction. The process is preferably carried out 8~'~
with the use of several extraction autoclaves which can be connected in series or in parallel and which can be removed individually from the process cycle.
After ending of the recycling, there is thus obtained a moist tea with a greatly reduced caffein content and a practically unchanged aroma material content.
~his tea is then dried, preferably at a temperature o from 60 to 80C., and can then be used directly.
In the case of the adsorption of the caffein on to the actlve charcoal, a temperature of from 50 ; to 70C. is preferably maintained. The recycling of the carbon dioxide to the already extrac-ted tea, with ; remoistening thereof, preferably takes place in a temperature range of from 50 to 70C. and more preferably of from 60 to 70C.
The caffein-containing active charcoal can be extracted with a solvent, the caffein separated from aroma substances by salt formation and the aroma substances again added to the extracted tea.
~he extraction of the tea can be carried out ~ in a conventional autoclave which is filled with tea ; and through which carbon dioxide then flow~ in the longitudinal axis. Such an extraction autoclave preferably has a cylindrical shape and can typically 25 have a length to diameter ratio of about 3:1 to 8:1.
Such extraction autoclaves are of simple construction and can easily be supplied with material to be , ~8~
extracted by means of a removable lid.
~ 2 have found that in the case of an extraction autoclave constructed in this manner, an undesired solidification of the filling material frequently occurs. The reason for this is that, in the case of tea, as well as also in the case of most other natural materials, because of their particulate form, a high degree of cohesivity is present. In addition, process parameters, such as the degree of moisture, the carbon dioxide volume flow~ the rate of compress-ing and the changing velocities of the volume stream~
also bring about a tendency to solidification.
In the case of commencement of a solidification of the loosely packed material, the loss of pressure during the flowthrough of the packing increases, which results in a further solidification. The result of thi~ is a canal formation which, in turn, brings about inhomogeneities of the degree of extract-ion referred to the cross-section and height of the autoclave. This can result in a considerable pro-longation of the necessary extraction time~.
According to a preferred embodiment of the present invention, these disadvantages can be overcome by arranging the material to be extracted, namely tea, i ` 25 in the form of a hollow cylinder, the extraction being carried out concentrically by introducing unloaded carbon dioxide from a cylindrical surface, the loaded .
carbon dioxide collecting behin~ the other cylindrical surface and being passed from there to the active charcoal. The introduction of the carbon dioxide thereby takes place especially preferably from the outer cylindrical surface. In the case of an approp-riate shaping of the hollow cylinder, ther~ is hereby also provided the possibility of arranging the active charcoal in the inner space of the hollow cylinder, especially favourable flow conditions thereby being provided.
According to this preferred radial flow method, the flowed-through cross-section changes continuously on the path from one surface of the hollow cylinder to the other surface thereof in which direction the flowthrough must take place. In the case of the especially preferred embodiment with flowthrough from the outside to the inside, in comparison with the usual axial flowthrough of a cylindrically shaped extraction autoclave, the packed material mantle surface impinged against is 15 to 20 times greater, at the end upon reaching the internal hollow chamber about five times greater, depending upon the diameter of the inner hollow chamber. Correspondingly low are also the empty tube as well as the canal velocities between neighbouring particles. In the case of unchanged average residence time within the autoclave, the period of contact on an individually considered - 9- ~2:~8~2 particle is considerably increased.
The mechanical stressing of the packing is also considerably reduced in the case o~ this embodiment.
The pressure loss depends, as is known, quadratically upon the empty tube velocity and is directly proport-ional to the running pat~ of the fluid. Therefore, in the case of the radial flow method of extraction, the running path of the carbon dioxide is only about one tenth of the running path in the case of axial 10wthrough of the autoclave. Pressings of the pack-ing material are, therefore, avoided.
The especially preferred embodiment of the ; extraction with radial flowing in the case of the introduction of the extraction fluid from the oute-r cylindrical mantle has, in addition, the advantage that, in the hollow inner chamber of the hollow cylinder, there can be provided the active charcoal, In this way, pressure losses in pipes between extraction autoclaves and separation autoclaves are avoided and an especially advantageous mode of operation is possible.
The invention is illustrated in particular and pref ~ ed I e~bodiments ky reference to the accompanying drawings in which:
i Fig. 1 is a schematic illustration of a device accord~ to the present invPntion, which is explained in more detail in the Example; an~
:. ' ;
Fig. 2 is an illus~ation of an ~traction autoclave with raaial flow~ough ~ccord~g to the prese~t invention.
A device according to the present invention f~r carrying out the radial extraction process, such as is illustrated, for example in Fig. 2 of the accompany-ing drawings, comprises a cylindrical autoclave 1, an extraction agent inlet 2, a lid 3 and an extraction agent removal means 4 and has a cylindrical extraction material container 5, placed in the autoclave, with a perforated mantle 6 and a per~orated extraction agent collecting cylinder 7, arranged in the cylinder axis, which is in flow connection with the extraction agent removal means 4. The perforated extraction agent collecting cylinder 7 can have a tubular shape. This is especially preferred when the extraction fluid is to be collected and passed directly from the extraction autoclave via the extraction agent removal means 4 to a separate separation autoclave with active charcoal filling~
However, according to a special embodiment of the device according to the present invention, the extraction agent collecting cylinder 7 has an active charcoal filling, a separate separation autoclave thereby being rendered superfluous. '~he extraction material container 5 can have an annular-shaped lid 8 through which extends the extraction agent collection cylinder 8.
.
., :
:
' In the case of the device according to the present invention, there is obtained a uniform flow over the packing to be extracted.
~he container 5 for the material to be extracted S can be arranged fixedly in the autoclave 1 or can be removable therefrom. Depending thereon, the supply-ing with the material to be extracted takes place into the cylinarical autoclave or also after removal of the container for the material to be extracted.
The extraction agent collection cylinder 7 is prefer-ably constructed in such a manner that, in the case of filling with the packing material, it can be removed from the device ~his simplifies the empty-ing of the packing material. Before renewed filling, the pipe is then again inserted. However, the collection cylinder can also be fixedly installed.
The embodiment of the process and of the device according to the present invention with radial flow-through of the material to be extracted can, in principle, be used for any kind of packing materials which are to be subjected to a high pressure extraction with an extraction agent, such a9 carbon dioxide.
The following Example is given for the purpose of illustrating the present invention, reference thereby being made to the accompanying drawings~
Exam~le.
10 kg. of a Ceylon blend type of tea containing 5.9% by weight of water and 3.3% by weight of caffein are moistened with 3.5 litres of water in a mixing apparatus and subsequently placed in an extraction autoclave (E). Adsorber (A) is provided with 7 kg.
active charcoal. The extraction autoclave and the adsorber are brought to a pressure of 200 bar with carbon dioxide from a liquid storage vessel (V~ with the help of a pump Pl, whereafter the pump is taken out of the circulation. After switching on pump P2, carbon dioxide is circulated via the extraction autoclave and the adsorber, the temperature in the èxtraction autoclave thereby being increased to 63C.
by heat exchanger Wl. The pressure in the extraction autoclave is 290 bar. The adsorber is operated at a pressure of 280 bar and at a temperature of 61 C.
After ~.5 hours, the extraction is discontinued, the carbon dioxide in the extraction autoclave is let off up to pressure equalisation in the carbon dioxide storage vessel and thereafter released into the atmosphere. The tea is removed from the extraction autoclave and dried in a drier at 70C~ The extracted tea thus obtained has a residual moisture content of 4.5% by weight of water and a caffein content of 0.08% by weight.
Claims (18)
1. A process for the production of decaffeinated tea by extraction with carbon dioxide, which is supercritical with regard to pressure and temperature, in the presence of water, comprising:
extracting a tea which has been adjusted to a water content of 15 to 50% by weight, at 50 to 70°C. with moist carbon dioxide at a pressure of from 260 to 350 bar, removing caffein from the resulting caffein-containing carbon dioxide in the same pressure range with active charcoal and thereafter recycling the resulting caffein-free carbon dioxide over the already extracted tea, separating the tea from the carbon dioxide, and drying the tea.
extracting a tea which has been adjusted to a water content of 15 to 50% by weight, at 50 to 70°C. with moist carbon dioxide at a pressure of from 260 to 350 bar, removing caffein from the resulting caffein-containing carbon dioxide in the same pressure range with active charcoal and thereafter recycling the resulting caffein-free carbon dioxide over the already extracted tea, separating the tea from the carbon dioxide, and drying the tea.
2. A process according to claim 1, wherein, before the extraction, the tea is adjusted to a water content of from 28 to 40 % by weight.
3. A process according to claim 2, wherein, before the extraction, the tea is adjusted to a water content of from 28 to 35% by weight.
4. A process according to claim 1, 2, or 3, wherein the carbon dioxide is maintained at a pressure of from 260 to 300 bar.
5. A process according to claim 1, 2 or 3, wherein the carbon dioxide is maintained at a pressure of from 270 to 290 bar.
6. A process according to claim 1, 2 or 3, wherein the extraction is carried cut at a temperature of from 60 to 70°C.
7. A process according to claim 3, wherein the extraction is carried out at a temperature of from 60 to 70°C and the carbon dioxide is maintained at a pressure of from 270 to 290 bar.
8. A process according to claim 1, 2 or 3, wherein 2 to 20 kg. of carbon dioxide are used per gram of caffein to be extracted from the tea.
9. A process according to claim 1, 2 or 7, wherein 3 to 10 kg. of carbon dioxide are used per gram of caffein to be extracted from the tea.
10. A process according to claim 1, 2 or 7, wherein the caffein-containing active charcoal is extracted with a solvent, caffein is separated from aroma substances by salt formation and the aroma substances are again added to the extracted tea.
11. A process according to claim 1, wherein the tea is arranged in the form of a hollow cylinder and the extraction is carried out concentrically by introducing unloaded carbon dioxide from one cylinder surface and the loaded carbon dioxide collected on an opposite-lying cylinder surface and passed to the active charcoal.
12. A process according to claim 11, wherein the carbon dioxide is introduced from an outer cylindrical surface and collected in a hollow chamber of the cylinder.
13. A process according to claim 12, wherein the active charcoal is arranged in an inner chamber of the hollow cylin-der.
14. A device for the production of decaffeinated tea which comprises a cylindrical autoclave with an extraction agent inlet for carbon dioxide, a lid and an extraction agent removal means, a cylindrical extraction material container with a perforated mantle disposed in the autoclave and an extraction agent collection cylinder having a perforated wall arranged along the axis of said container, said collection cylinder being in flow connection with the extraction agent removal means, and said extraction agent inlet being in flow communica-tion with said perforated mantle, said device having a flow path for carbon dioxide passing sequentially from said inlet into said autoclave through said perforated mantle into said container, from said container through said perforated wall into said collection cylinder and thence to said removal means.
15. A device according to claim 14, wherein the per-forated extraction agent collection cylinder is constructed in the form of a pipe.
16. A device according to claim 14 or 15, wherein the extraction agent collection cylinder has an active charcoal filling.
17. A device according to claim 14 or 15, wherein the extraction material container has an annular-shaped lid through which extends the extraction agent collection cylinder.
18. A device according to claim 14 or 15, wherein said extraction agent removal means is in flow communication with said inlet for recycling of the extraction agent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3415844.8 | 1984-04-27 | ||
| DE3415844A DE3415844C2 (en) | 1984-04-27 | 1984-04-27 | Process for the production of decaffeinated tea |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1248812A true CA1248812A (en) | 1989-01-17 |
Family
ID=6234567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000480013A Expired CA1248812A (en) | 1984-04-27 | 1985-04-24 | Process for the production of decaffeinated tea |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0159724B2 (en) |
| JP (1) | JPS60234548A (en) |
| AT (1) | ATE64825T1 (en) |
| CA (1) | CA1248812A (en) |
| DE (2) | DE3415844C2 (en) |
| SU (1) | SU1602385A3 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3339181A1 (en) * | 1983-10-28 | 1985-05-09 | Uhde Gmbh, 4600 Dortmund | METHOD AND DEVICE FOR DECAFFINATING TEA LEAVES |
| DE3515740A1 (en) * | 1985-05-02 | 1986-11-06 | Skw Trostberg Ag, 8223 Trostberg | METHOD FOR DECAFFINATING TEA |
| DE3640333C3 (en) * | 1986-11-26 | 1994-08-11 | Barth Raiser Hopfenextraktion | Process and apparatus for the preparation of flavored, decaffeinated tea |
| DE3640967A1 (en) * | 1986-11-29 | 1988-06-09 | Sueddeutsche Kalkstickstoff | METHOD FOR DEAROMATIZING AND THEN REAROMATIZING TEA |
| AT388114B (en) * | 1987-05-20 | 1989-05-10 | Ver Edelstahlwerke Ag | METHOD AND ARRANGEMENT FOR LOADING A PRINT SPACE |
| DE3838952A1 (en) * | 1988-11-17 | 1990-05-23 | Barth Raiser Hopfenextraktion | Process for aromatising (flavouring) treated tea |
| DE4400096C2 (en) * | 1994-01-04 | 1997-06-12 | Barth Raiser Hopfenextraktion | Process for decaffeinating black tea |
| DE19524481C2 (en) * | 1995-07-05 | 2000-03-02 | Hopfenextraktion Hvg Barth, Raiser & Co | Procedure for decaffeinating black tea |
| CA2572995C (en) | 2004-07-09 | 2010-12-07 | Nateco2 Gmbh + Co. Kg | Method for decaffeinating tea |
| GB201405488D0 (en) | 2014-03-26 | 2014-05-07 | Infre S A | Decaffeination methods and systems |
| EP3120712B1 (en) | 2015-07-22 | 2017-09-13 | Evonik Degussa GmbH | Method for improved extraction of juniper berries, rose hips, sea buckthorn berries, sorbus |
| EP3165099A1 (en) | 2015-11-03 | 2017-05-10 | Evonik Degussa GmbH | Removing oil and simultaneous removal of unwanted contaminants from beans with supercritical co2 |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH535543A (en) * | 1970-02-05 | 1973-04-15 | Studiengesellschaft Kohle Mbh | Process for decaffeinating green coffee |
| DE2127642C3 (en) * | 1971-06-03 | 1975-10-16 | Studiengesellschaft Kohle Mbh, 4330 Muelheim | Process for making caffeine-free, full-flavored black tea |
| DE2212281C3 (en) * | 1972-03-14 | 1978-11-18 | Hag Ag | PROCESS FOR DECOFFEINATING RAW COFFEE |
| US4247570A (en) * | 1976-08-04 | 1981-01-27 | Studiengesellschaft Kohle Mbh | Process for the decaffeination of coffee |
| DE2637197C2 (en) * | 1976-08-18 | 1983-01-27 | Hag Ag, 2800 Bremen | Process for the removal of caffeine from natural substances containing caffeine with a supercritical extractant |
| DE2639066A1 (en) * | 1976-08-30 | 1978-03-02 | Hag Ag | METHOD OF REMOVING IRRITANTS FROM COFFEE |
| DE2727191B2 (en) * | 1977-06-16 | 1980-07-03 | Hag Ag, 2800 Bremen | Process for the selective extraction of caffeine from plant materials |
| DE3339181A1 (en) * | 1983-10-28 | 1985-05-09 | Uhde Gmbh, 4600 Dortmund | METHOD AND DEVICE FOR DECAFFINATING TEA LEAVES |
| DE3414767A1 (en) * | 1984-04-18 | 1985-11-07 | Hopfenextraktion HVG Barth, Raiser & Co, 8069 Wolnzach | Process for producing decaffeinated black or green tea |
| EP0167399A3 (en) * | 1984-07-06 | 1987-08-26 | General Foods Corporation | Decaffeination of fermented unfired tea |
-
1984
- 1984-04-27 DE DE3415844A patent/DE3415844C2/en not_active Expired - Fee Related
-
1985
- 1985-04-10 SU SU853877651A patent/SU1602385A3/en active
- 1985-04-24 CA CA000480013A patent/CA1248812A/en not_active Expired
- 1985-04-26 DE DE8585105153T patent/DE3583354D1/en not_active Expired - Lifetime
- 1985-04-26 JP JP60089148A patent/JPS60234548A/en active Granted
- 1985-04-26 AT AT85105153T patent/ATE64825T1/en not_active IP Right Cessation
- 1985-04-26 EP EP85105153A patent/EP0159724B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0159724A3 (en) | 1988-07-20 |
| JPH053258B2 (en) | 1993-01-14 |
| ATE64825T1 (en) | 1991-07-15 |
| DE3583354D1 (en) | 1991-08-08 |
| EP0159724B2 (en) | 1998-01-07 |
| DE3415844A1 (en) | 1985-10-31 |
| SU1602385A3 (en) | 1990-10-23 |
| JPS60234548A (en) | 1985-11-21 |
| DE3415844C2 (en) | 1994-02-03 |
| EP0159724A2 (en) | 1985-10-30 |
| EP0159724B1 (en) | 1991-07-03 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |