CA1090192A - Decaffeination process - Google Patents
Decaffeination processInfo
- Publication number
- CA1090192A CA1090192A CA239,458A CA239458A CA1090192A CA 1090192 A CA1090192 A CA 1090192A CA 239458 A CA239458 A CA 239458A CA 1090192 A CA1090192 A CA 1090192A
- Authority
- CA
- Canada
- Prior art keywords
- caffeine
- fatty material
- fatty
- beans
- water
- 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
Links
Classifications
-
- 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
-
- 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
- A23F3/38—Reducing or removing alkaloid content from tea extract
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/20—Reducing or removing alkaloid content; Preparations produced thereby; Extracts or infusions thereof
- A23F5/206—Reducing or removing alkaloid content; Preparations produced thereby; Extracts or infusions thereof by extraction of the beans with selective solvents other than water or aqueous bean extracts, including supercritical gases
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/20—Reducing or removing alkaloid content; Preparations produced thereby; Extracts or infusions thereof
- A23F5/22—Reducing or removing alkaloid content from coffee extract
- A23F5/226—Reducing or removing alkaloid content from coffee extract by extraction with selective solvents
Abstract
ABSTRACT OF THE DISCLOSURE
A process for producing a decaffeinated vegetable material comprising contacting a liquid, water-immiscible fatty material with a caffeine-containing vegetable mate-rial, maintaining said fatty material and vegetable mate-rial in contact for a period of time sufficient to trans-fer caffeine from said vegetable material into said fatty material, and separating the resultant, caffeine-laden fatty material from the decaffeinated vegetable material.
A process for producing a decaffeinated vegetable material comprising contacting a liquid, water-immiscible fatty material with a caffeine-containing vegetable mate-rial, maintaining said fatty material and vegetable mate-rial in contact for a period of time sufficient to trans-fer caffeine from said vegetable material into said fatty material, and separating the resultant, caffeine-laden fatty material from the decaffeinated vegetable material.
Description
Ol~Z
This invention is concerned with the decaffeination of vegetable materials.
There has long been a recognized demand for decaffeina-ted vegetable materials, particularly beverages such as cof-fee and tea. The customary prior art techniques for decaffei-nation generally involve the use of organic solvents such as trichlorethylene or chloroform, which solvents are contacted either with the vegetable material or with an aqueous extract thereof. When sufficient caffeine has been transferred to the solvent, the resultant solution of caffeine is separated so as to allow further processing of the decaffeinated material or extract.
These organic solvent-based decaffeination techniques have several disadvantages. Of particular concern to the ul-timate consumer, the utilization of prior art decaffeinationsolvents often results in substantial loss, or denaturization, of valuable flavour and aroma constituents of the eventual beverage. Thus, decaffeination has frequently been responsible for products lacking in high quality characteristics.
Further, because the prior art solvents themselves are often detrimental, concern has been evidenced respecting con-tacting them with vegetable materials from which comestibles are to be produced. This concern has resulted in the develop-ment of complex and stringent processing techniques in order to insure complete solvent separation from the finished pro-ducts.
This invention is concerned with the decaffeination of vegetable materials.
There has long been a recognized demand for decaffeina-ted vegetable materials, particularly beverages such as cof-fee and tea. The customary prior art techniques for decaffei-nation generally involve the use of organic solvents such as trichlorethylene or chloroform, which solvents are contacted either with the vegetable material or with an aqueous extract thereof. When sufficient caffeine has been transferred to the solvent, the resultant solution of caffeine is separated so as to allow further processing of the decaffeinated material or extract.
These organic solvent-based decaffeination techniques have several disadvantages. Of particular concern to the ul-timate consumer, the utilization of prior art decaffeinationsolvents often results in substantial loss, or denaturization, of valuable flavour and aroma constituents of the eventual beverage. Thus, decaffeination has frequently been responsible for products lacking in high quality characteristics.
Further, because the prior art solvents themselves are often detrimental, concern has been evidenced respecting con-tacting them with vegetable materials from which comestibles are to be produced. This concern has resulted in the develop-ment of complex and stringent processing techniques in order to insure complete solvent separation from the finished pro-ducts.
- 2 -~Q~019Z
In accordance wlth the present lnventlon, there ls pro-vided a process for producing a decaffelnated vegetable mate-rial comprising contacting a liquid, water-immiscible fatty material with a caffeine-containing vegetable material, main-taining said fatty material and vegetable material in contactfor a period of time sufficient to transfer caffeine from said vegetable material into said fatty material, and separating the resultant, caffeine-laden fatty material from the decaf-feinated vegetable material.
By "fatty material" as the term is utilized herein, is meant any of the animal or vegetable fats or oils or admix-tures or fractions thereof which assume a liquid form within the temperature range -- discussed hereinafter -- useful for the removal of caffeine from a caffeine-containing composi-tion. These fatty materials are customarily composed essen-tially of esters of fatty acids -- usually glycerol esters --and may be utilized in either their native form or in those resultant from conventional treatments as are known in the art. Moreover, the fatty materials used should desirably be non-solvants for constituents of the vegetable material other than caffeine.
Thus, for example, the present fatty materials may be in either unsaturated or saturated fats or oils. Similarly, unre-fined or conventionally refined oils as well as oils with or without such normal additives as anti-oxidants and preserva-tives are all useful within the scope of the present invention.
10~1019Z
It ls preferred, however, that the fatty materlal be essen-tlally exempt of surfactants, elther naturally - present or added. These materlals may stabilize emulsions which form upon agitation of liquid compositions utilized in accordance with the present invention and therefore increase the diffi-culty of such processing steps as centrifugal separation as may be required.
The fatty materials of the present invention include commercial oils and fats and thus numerous examples are raa-dily available. Of these fatty materials, however, thosewhlch are edible are highly preferred because their utiliza-tion reduces the need for special care in separation from ve-getable materials which will be further processed as comestib-les.
These fatty materials are useful for effecting virtually any desired degree of decaffeination of a vegetable material.
Thus, although essentially complete caffeine removal is ordi-narily preferred, a lesser degree can also be provided upon consumer demand. In either event, however, a corresponding amount of caffeine will become available as a valuable, com-mercial by-product.
The fatty materials are utilized to extract caffeine from various vegetable materials, most commonly from coffee or tea. In order, however, for decaffeination to proceed rea-dily, it is desirable that there be water present. It is be-lieved that this requirement is due to the desirability of ~(.~(~192 providing the caffeine in an initially water-solubilized or partially water-solubilized form, so as to facilltate its availability to the fatty material decaffeination solvent.
This belief as to a mechanism by which the present invention may operate is not, however, intended to limit the scope of the present invention but rather is set forth merely as an attempt at explanation of what may be occurring incident thereto.
Caffeine-containing vegetable materials which may be de-caffeinated in accordance with the present invention are mostsuitably provided in either aqueous liquid or solid form.
Where a solid form is employed, water should still be present, although it may be bound within the solid. Accordingly, aqueous solutions of vegetable material and vegetable materials having a substantial moisture content are preferred compositions for decaffeination in accordance with the present lnvention.
Aqueous extracts of tea or roast ground coffee are well-known and may be produced by means conventional in the art.
Because these extracts are themselves eventually converted into beverage products, however, they should ordinarily be treated in a manner so as to minimize exposure to conditions which might result in loss and/or degradation of valuable flavour constituents. One particular class of constituents of these brews -- the so-called volatiles or aromatics -- is particularly sensitive in this regard.
Accordingly, they are preferably removed early during processing and recombined with the more stable constituents only at or near the end of the beverage production cycle.
This removal and preservation of the volatile or aroma-tic constituents of vegetable materials may be accomplished by means well-known in the art. Thus, for example, it is con-ventional to subject aqueous extracts to stripping with steam, through which technique an aqueous condensate containing the aromatic and volatile constituents is readily obtained. Such isolates are then preserved under conditions of low tempera-ture until such time as they may be recombined with the pro-cessed vegetable material constituents, for example, by ad-mixture therewith immediately preparatory to drying or through application to the dried material itself followed by a short, secondary drying sequence. Accordingly, where aqueous extracts are decaffeinated with the fatty materials, the aqueous solu-tion of vegetable material is pr~ferably free of its customary volatile constituents.
Another liquid vegetable material which may be decaffei-nated in accordance with the present invention comprises an aqueous extract of the vegetable material, which has been formed specifically for the purpose of decaffeination and will not constitute any portion of the eventual beverage pro-duct. This embodiment of the present invention is most sui-table for vegetable materials such as coffee which normally require roasting or some other treatment to form many of their desired beverage constituents.
~0~92 Exemplary of thls embodiment of the present inventlon i8 an aqueous extract of green coffee beans. Such beans may be extracted with water so as to remove their caffeine content.
The resultant extract, however, contalns relatively few of the normal coffee beverage constituents inasmuch as these water-soluble constituents are largely produced only upon subsequent roasting of the beans.
The formation of this extract is fairly simple. All that is requlred is that the green beans be contacted with a weight of water sufficient for dissolving their caffeine content, the beans normally containing about 2 to 3 weight percent caffelne depending on thelr origin. Ordinarily, dissolution is accom-plished by counter-current flow of beans and water; however, thls step can be effected simply by slurrying the beans in water or any equivalent contact therebetween for a perlod of time -- usually 10 to 60 minutes -- sufficient to allow the desired degree of decaffeination.
Even where green beans are extracted with water, however, some valuable beverage constituents may also be removed to the aqueous phase. One technique by which the avoidance of any sub-stantial loss of these desired constituents has been insured is through closed, cyclic circulation of the aqueous extraction medium. Pursuant to this technique, the aqueous medium rapidly obtains its maximum concentration of the various water-soluble constituents, including caffeine, of green beans. Upon subse-quent selective removal of the caffeine from the medium, there 10!~01~2 is obtained a recyclable aqueous extraction medium which ra-pidly approaches dynamic equilibrium with respect to those water-soluble constituents of green beans which are not re-moved by decaffeination of the medium.
With such a dynamic equilibrium in effect, the recycled caffeine-free extraction medium will -- upon recontact with green coffee beans -- remove essentially only caffeine there-from. Thus, within a short time, a system may be obtained whereby essentially only caffeine is removed from the green beans.
Both, the recirculating extraction medium and the aqueous extract discussed more completely above all essentially aqueous solutions which contain both caffeine and various water-soluble vegetable material constituents. Accordingly, the present tech-nique of treating liquid vegetable materials with fatty mate-rial to remove caffeine therefrom may be applied to each in much the same manner. Thus, a liquid vegetable material is ad-mixed with a suitable volume of a liquid water-immiscible fat-ty material, maintained in admixture therewith until caffeine has migrated into the fatty material, and then separated with a corresponding decrease in its caffeine content. These steps may be accomplished quite simply, because the fact that both phases are liquid permits easy and thorough admixture under agitation, while the immiscibility of the two phases -- aqueous and fatty -- allows substantially complete separation by many known techniques, including decantation.
l(!~iO~
Of ma~or lmportance for the efflclency of decaffelna-tlon are the caffeine solubillty characterlstlcs of the fatty materlal. These propertles are dependent upon the particular materlal selected and the temperature durlng admlxture wlth the liquid vegetable material. Thls effect may be discussed ln terms of the distribution coefficient for caffelne between equal volumes of the fatty and aqueous phases durlng admlx-ture and at equilibrium. More particularly, the afflnity of the fatty material for caffeine is defined by the relation-shlp:
Distrlbution coefficient = caffeine concentration in fatty phasecaffeine concentration in aqueous phase for any glven temperature. Clearly then, higher dlstribution co-efficients evidence a superior ability to effect decaffeination.
In Table I which follows, exemplary data for various fatty materials at different temperatures are provided. The data re-flect the equilibrium achieved by single admixtures of volumes of fatty material and aqueous caffeine solutions. It should be understood that the fatty materials actually utilized are only representative commercial products. Thus, depending on the par-ticular history of a given material, some variation in the dis-tribution coefficient would be expected. With this data and the additional description provided herein, however, the characte-ristics and optimum conditions of use for other fatty materials within the scope of the present invention may easily be deter-mined.
_ g _ TABLE I
SOLUBILITY CHARACTERISTICS OF FATTY MATERIALS
Fatty Material Temperature Caffeine Distribution Coeffi-cient for Equal Volumes of _ Aqueous and Fattv Phases Safflower Oil 20 C .064 10 C .067 Soy Bean Oil 20 C .064 10 C .05g Corn Oil 20 C .064 15 C .064 10 C .071 5 C .085 Peanut Oil 10 C .067 Coffee Oil 23 C .140 Triolein (oleic acid ester of glycerol) 23 C .085 Olive Oil 23 C .076 Lard 65 C .197 The time of contact between fatty and vegetable phases is relatively unimportant. Only a few minutes are required for approaching the equilibrium degree. The optimum tempera-ture for decaffeination with any particular fatty material within the scope of the present invention hcwever should be determined prior to utilization. Exemplary data are reflected in Table I, but additional determinations may be made by well-known techniques and thus this aspect of the present invention may be ascertained by simple experimentation after selection of the particular fatty material to be utilized.
1~019Z
In determining the optlmum temperature, the partlcular materlals lnvolved place llmlts on the degree of deslrable varlation. Thus, the freezlng polnt of the aqueous vegetable material and the solidlfication point of the fatty material define the lower limit for useful temperatures. At the other end of the range, the degradation to flavour whlch may result upon exposure of flavour and aroma constltuents to hlgher tem-perature should also be avolded. Normally, however, decaffel-natlon can be effected within the range of from 0 to 50 C, wlth from 10 to 30 C being preferred for aqueous extracts.
Where these constituents are essentlally absent, stlll hlgher temperatures, up to the lnstability point for the particular vegetable material remain useful.
Once a particular fatty material and temperature for the decaffeination step have been selected, there remains the con-sideration of the desired degree of decaffelnatlon. This is usually controlled, at least partly through the ratlo of vege-table to fatty materials. Ordinarily, a ratlo of fatty mate-rial to aqueous vegetable materlal of about 20 : 1 will achleve only partial decaffeination in a single contacting sequence.
Thus, for example, at that ratlo, dlstrlbutlon coefficients of .035 and .085 yield about 40 % and 65 % decaffeinatlon respec-tlvely. Increases in the ratlo of fatty to vegetable materlal wlll, of course, lncrease thls degree of deoaffeination just as lower ratios decrease it.
Additionally, however, the means through which contactlng ~Ol~Z
wlth fatty materlal ls accompllshed affects the degree of de-caffelnatlon. Decaffelnatlon can occur as prevlously descrlbed, through a one-step decaffelnatlon sequence includlng contact-lng a partlcular welght of fatty materlal wlth a partlcular welght of aqueous extract, malntalnlng such materlals ln con-tact for a perlod sufflcient to approach or reach the caffeine dlstrlbutlon equlllbrlum, and then separatlng the extract. The efflclency of decaffelnation may however be increased by ln-creasing the number of steps. Accordlngly, in a preferred em-bodiment of the present lnventlon, decaffelnatlon i8 performedln a multl-step sequence, whereln the vegetable materlal is contaoted wlth successlve allquots of the fatty materlal untll the deslred degree of decaffelnation has been reached.
Thls preferred embodiment may most slmply be followed by successlvely contactlng the caffelne-contalning composltlon wlth allquots of a partlcular fatty materlal, malntalnlng the fatty and aqueous phases ln contact for a perlod of tlme suf-flclent to effect a substantial transfer of caffeine lnto the fat~y materlal (such a transfer ordlnarily belng in an amount greater than about 70 % of the equlllbrium dlstributlon there-ln), separating the aqueous and fatty phases and then repeat-lng thls sequence of steps wlth additlonal al$quots of caffelne-free fatty materlal.
Stlll another form of this preferred embodiment comprlses counter-current decaffeination. Therein, an initially caffelne-free fatty materlal is passed through consecutive volumes of :103~)~9~
vegetable material which are arrayed in reverse order by caffelne content. Thus, the fresh fatty material flrst con-tacts the most decaffeinated vegetable material volumes, and then those of higher caffeine content. During this process embodiment, when the first vegetable material volume reaches the desired degree of decaffeination, it is simply by-passed while a new volume -- having the highest caffeine content --is connected down-stream, to maintain a constant number of vo-lumes on stream and a proper order of contact with the fatty material.
It is additionally noted that aqueous solutions or ex-tracts of vegetable material may contain, for example, from 2 to 60 % soluble solids by total weight. Ordinarily, however, it is preferred that the solutions to be decaffeinated have a soluble solids concentration of from 10 to 50 %, preparatory to contacting with the fatty material caffeine solvent. Such concentrations are preferred for the purpose of minimizing the subsequent volumes of liquids which may be utilized in the de-caffeination sequence, as well as for the purpose of reducing the quantity of water which must eventually be removed from a brew or extract which is to be dried to solid form.
Concentration may be obtained through techniques well known to the prior art. Again, because the aqueous extract will eventually provide the dried beverage product, it is de-sirable that such concentration be obtained under conditionswhich will minimize the possibility of adverse effect on fla-vour. Accordingly, lt ls preferred that technlques such aslow pressure evaporatlon or freeze concentratlon, which avold exposlng the brew to higher temperature for any sub-stantial period of tlme, be utilized.
The present invention also includes utilization of a fatty material for direct decaffeination of solid vegetable materials. Exemplary of such solids are green coffee beans which may be provlded in ground, crushed and, most desirably, whole form. Roast coffee beans may also be utilized; however volatiles should first be removed to avoid undue loss of va-luable beverage constituents. Consequently, the decaffeination of whole green beans is most preferred and the following dis-cussion of this embodiment is particularly directed thereto, although other vegetable materials may be treated in similar manner.
Use of solid vegetable materials is a particularly pre-ferred embodiment of the present invention inasmuch as it ob-viates certain disadvantages of dealing with aqueous solutions of vegetable material. Thus, the separation of the fatty mate-rial from the caffeine-containing composition is facilitated by the fact that, while the fatty material remains liquid, the vegetable material is in solid form. Separation of the beans and fatty material may even conveniently be effected by simple drainage of the beans and, where centrifugal force is utilized to facilitate this separation, fairly simple machinery is ade-quate.
~0~0192 Further, in the separatlon of green coffee beans from a liquid fatty material, the degree of separation may be es-sentially 100 %. Whereas even the most sophisticated of immis-cible liquid separations may result in some retainment of one liquid in the other, no such problem is encountered here. Once most of the fatty material has been separated from the beans, a secondary physlcal purification step, such as dlrection of a burst of steam through the beans, permlts essentially 100 %
separation of retained fatty material. Moreover, even this additional step may be rendered unnecessary. Because of the post-decaffeination roasting and extractive processing of the beans, where a substantially flavourless fatty material is uti-lized, little if any effect upon the flavour of the eventual beverage product will result even if separation is incomplete.
In order to be in a form readily susceptible to caffeine removal, green coffee beans should contain some moisture. The beans ordinarily naturally contain from 8 to 10 % moisture, although higher amounts, of at least about 20 ~ by total weight, are preferred. The upper limit of moisture content, however, is more variable. Decaffeination of a caffeine-containing composi-tion comprising green beans is desirably performed in the ab-sence of free liquid water, so as to avoid the separation pro-blems incident to an admixture of liquids and the possible loss of valuable vegetable material constituents solubilized in that water. Accordingly, in this embodiment of the present invention, it is preferred that the green beans contain between about 20 , and 60 %, most preferably between about 40 and 60 %, water by total weight.
The incorporatlon of water into green beans is easily accomplished. Thus, for example, the beans may simply be im-mersed in water and there maintained for several hours, untilthey have absorbed the desired amount of moisture. Thereafter, they may easily be separated from the excess water, for exam-ple, by centrifugation. Through the use of heat and/or pres-sure, this incorporation or "swelling" of the beans may be accelerated. Thus, for example, where beans are immersed in water at a temperature of about 80 to 90 C, they achieve the desired moisture content much more quickly. Also, upon being subjected to steam at about 2 atmospheres, even less tlme --normally about 1 to 30 minutes -- is sufficient to reach the desired moisture content.
Once the beans have been swollen to an appropriate mois-ture content, they are placed in a bath or stream of fatty ma-terial until the desired degree of decaffeination has been achieved. Here, the time of admixture becomes significant :
transfer of caffeine from the beans is much slower than from dilute solution. Accordingly, it is desirable that periods of at least 30 minutes, with longer periods for more complete de-grees of decaffeination, be permitted for this step.
In processes leading to high degrees of decaffeination, it is also important to ensure that the moisture content of the swollen beans does not significantly decrease during treat-; - 16 -lQ~:)19Z
ment. Contact between swollen beans and fatty material can result in lower moisture contents due to loss of water from the beans to the fatty material. Where this decrease brings the beans to a moisture content below the preferred 40 to 60 % range, there occurs a corresponding decrease in the ef-ficlency of decaffeination.
It is therefore preferred that the fatty material uti-lized for decaffeination contain a small amount of water.
From 0.9 to 1.2 %, most desirably about 1.0 %, of water by weight of fatty material is ordinarily utilized in this pre-ferred embodiment of this invention. This amount acts to maintain in equilibrium the amount of water present in the beans and the fatty material, so that during contacting there is no net migration of water from the beans to the fatty phase, nor vice-versa. On the other hand, it prevents excessive remo-val of water from the beans, and on the other it minimizes the total amount of water present during decaffeination, thereby avoiding undue loss of non-caffeine, water-soluble bean con-stituents.
Again, the use of multi-step as opposed to single-step contact of fatty material with the vegetable material may be practiced in the manner previously described. Thus co-current and, more preferably, counter-current extraction with fatty material are desirable embodiments of the present invention.
One aspect by which the decaffeination of swollen green beans differs substantially from decaffeination of aqueous lQ~3019Z
caffelne-contalnlng solutlons lies ln the effect of tempera-ture upon the efficlency of decaffelnatlon. As previously no-ted, where decaffeination involves the contacting of fatty ma-terial with an aqueous caffeine-containing solution, differen-ces in temperature during such contact~ng do not have a largeeffect upon the efficlency of decaffelnatlon. In treating so-lid beans, however, increases in the prevaillng temperature for decaffelnation may dramatically increase the rate of caf-feine removal.
Accordingly, to achieve maximum efficiency of caffeine removal, decaffeination of beans is preferably carried out at as high a temperature as is practicable. Degradation of fatty materials customarily occurs at or around a temperature of about 150 C, and therefore this temperature usually repre-sents a practical maximum limit for decaffeination. Also, pro-longed contact times at very high temperatures may produce some degradation of flavour constituents. Accordingly, it is prefer-red that the decaffeination of green beans be performed within the temperature range of from about 50 to 120 C.
A further aspect of the present invention involves rege-nerating caffeine-containing fatty material so as to permit reuse thereof in the decaffeination process. This is most ef-ficiently achieved by contacting the separated caffeine-con-talning fatty material with water, permitting the transfer of the caffeine into aqueous phase, and then separating the fatty material to permit its recycle for further decaffeination. In large measure, the regeneration sequence reverses the steps already described above with respect to decaffeinatlon. In addition, however, it readily permits isolation of the caf-feine from the regenerate aqueous phase.
For regeneration of the fatty material, the efficiency of caffelne removal to aqueous phase is again governed by the same parameters of temperature, the caffeine distribution co-efficient of the particular fatty material, and the weight ratio of fatty material to water as discussed above with res-pect to the separation of caffeine from an aqueous solution of vegetable material.
Because flavour degradation is not a serious problem du-ring regeneration, as constituents of the final product are not present, the temperature during regeneration may be raised to improve the efficiency of caffeine transfer to the aqueous phase. Thus where, with increasing temperature, the solubility of caffeine in water increases more rapidly than in the fatty material, it is advantageous to effect regeneration at a tem-perature up to 100 C (and even higher where pressure is uti-lized to avoid evaporation). If on the other hand, lower tem-peratures favour this transfer then they should be employed.
Also, because it is here desired to transfer caffeine from the fatty material to an aqueous phase, the relatively greater solubility of caffeine in water permits the utiliza-tion of low fatty to aqueous phase ratios, even for substan-Z
tially complete transfer. Additionally, where lt is desired further to minlmize the amounts of water utlllzed in regene-ration of the fatty material, a multi-step regeneratlon se-quence comprising co-current or counter-current extraction of fatty material with water may be utilized in the same manner as has already been described hereinabove so as to facilitate the efficient regeneration of the fatty material.
Incident to regeneration of the fatty material through removal of caffeine with water, it has been discovered that the separated fatty material can contain -- even when separa-tion of these immisclble liquids is accomplished through such normally efficient means as centrifugal separation -- about 1 % by weight of water. This water is desirably removed from the fatty material before recontacting with vegetable mate-rial so as to avoid dilution of liquid vegetable materials.Removal of the entrained water in the fatty material can be accomplished by such means as a flash distillation under va-cuum conditions or equivalent known techniques.
As previously described, certain preferred embodiments of this invention relating to decaffeination of solid vege-table materials rely upon utilizing a fatty material contai-ning a small amount of water. In the practice of these embo-diments, the dilution factor becomes negligible. Therefore, the regenerated fatty material containing entrained water may be used directly for further decaffeination. Alternatively, its aqueous content may be adjusted -- for example, by adding lO9(~19Z
water or by partlal strlpplng -- as requlred to brlng lt to an optlmum water content.
Even where the presence of water ln the fatty material is desired, however it ls preferred to remove the entrained water and then add the desired amount of water to dry fatty material. This sequence of steps ensures an optlmum water content and avolds the difficulties and/or interruptlons re-quired for monitoring the entrained water content of regene-rated fatty materlal and then adjusting lt, as desired.
The followlng examples are lllustrative of the present inventlon. Unless otherwise noted, the percentages are on a weight basis.
An aqueous extract of roast ground coffee beans is stripped with steam to remove volatiles. 10 kilograms of the stripped extract, at a soluble solids concentration of 19 %
and a temperature of 22 C, are then added to 179 kilograms of corn oil at 60 C. The resultant admixture is agitated for 30 minutes and then passed through a centrifugal separa-tor at a rate of 3.16 kilograms per minute. The brew, whichis separated from the oil in the centrifuge, has a 51 ~ de-gree of decaffeination.
By repeating this treatment of the brew with additional corn oll, the degree of decaffeination is successively in-creased until essentially complete caffelne removal is effec-ted.
105~01~2 A tea extract having a soluble solids concentration of 27.6 % and a temperature of 22 C is mixed with corn oil in a volume ratio of 1 : 20, respectively, and maintained under agitation for 10 minutes. The admixture is then subjected to centrifugal separation to yield a tea extract exhibiting 63 %
decaffeination. Again retreatment affords a means for achiev-ing any greater desired degree of decaffeination.
ExAMæLE 3 Green coffee beans are decaffeinated utilizing a recir-culating aqueous medium which has reached an equilibrium so-luble solids concentration of 29 % and is at a temperature of 22 C. Decaffeination is performed by passing the aqueous me-dium in counter-current through a column of green beans, with essentially caffeine-free beans being removed from the column at one end and natural green beans added at the other. Within the circulating aqueous system, and at a point removed from the column, aqueous medium is diverted through a centrifugal extractor to which coffee oil at 50 C, in a ratio of 21 : 1 to the medium, is added for removal of caffeine from the aqueous extract. Heat exchangers in the system are used to maintain the temperatures of these two liquids essentially as indicated.
With a single pass of the medium and oil through the cen-trifuge, over one-third of the caffeine in the medium is re-moved. A second pass of the medium and a further equal aliquot 10~
of oil increases the decaffeinatlon of the medlum to over 60 %.
After roastlng, grlndlng and extracting separate samples of decaffelnated beans obtalned after the slngle and second pas-ses, lt ls found that both sample aqueous extracts are essen-tlally caffelne-free.
Green coffee beans are subjected to steam at 110 C untll they reach a molsture content of 45 ~ by total weight, and 10 kg aliquots are placed lnto separate extraction chambers. Each of the allquots is decaffeinated for four hours at 95 C wlth corn oil whlch ls passed through the chambers at a rate of 1.1 kg/mlnute.
In one Trial, "A", oil is passed through only one chamber.
Thereafter it is regenerated by extraction wlth water to remove lts caffeine content, the water is removed, and the oil is then recirculated to maintain a continuous flow of caffeine-free corn oll to swollen beans in the chamber.
In a second Trial, "B", four chambers are connected in se-ries so that the corn oil flows through each. Regeneration and recirculation of the oil is accomplished only after it has pas-sed through all four chambers. One chamber - the first contac-ted by oil - is removed each hour and a new chamber is added at the downstream end. In this manner, and after a start-up pe-riod of 6 hours a system is achieved wherein the four chambers contaln beans of varying caffeine content by virtue of the fact )l9Z
that they have been subjected to different duratlons of on-stream oil decaffeination.
The caffeine contents of beans from Trial "A" and from a chamber which has passed through all four stages of Trial "B" after start-up were analyzed. Despite the fact that each of these beans had been decaffeinated under essentially the same physical conditions, their respective degrees of decaf-feination are markedly different. Thus while the beans of Trial "A" exhibit 52 % decaffeination, those of Trial "B" ex-hibit 92 %. It is therefore evident that multi-step extraction substantially increases the efficiency of decaffeination.
An aqueous extract of roast ground coffee beans is strip-ped with steam to remove volatiles. 200 grams of the stripped brew having a soluble solids concentration of 18.4 % are then admixed with 2 kg of safflower oil and agitated for 30 minutes at 20 C. This admixture was then centrifuged to break the emulsion and the brew separated by decantation. The separated brew exhibits a 56 % degree of decaffeination.
The process of Example 5 is repeated with the change that 2 kg of soy bean oil are substituted for the safflower oil. After separation, the brew exhibits a 56 % degree of de-caffeination.
()192 The process of Example 5 is repeated substltuting 2 kg of peanut oil for the safflower oil. Additionally, the brew and oil are maintained at 10 C - instead of 20 C - through-out the process. The separated brew exhibits a 56 % degree ofdecaffeination.
Green coffee beans are decaffeinated with coffee oil in a four-chamber countercurrent extraction zone ln the manner described for Trial "B" of Example 4. Each chamber, or cell, contains 6.8 kg of beans by dry weight. The oil is maintained at 105 C and extraction is performed over a total extraction period of 6 hours (1.5 hours for each cycle). A total oil to bean weight ratio of 120 : 1 is utilized.
After each pass of the recirculating oil through all four chambers of the extraction zone, the oil regenerated by aqueous extraction for caffeine and then is stripped to remove its aqueous content. A predetermined measure of water is ad-mixed with the oil preparatory to its recirculation.
, ~ ~
Utilizing the foregoing procedure, five different Trials are made. These Trials differ essentially in the addition of varying amounts of water to stripped, caffeine-free fatty ma-terial. Data for steady-state conditions of operation of each Trial are as follows:
lO9015~Z
Tri~l Water Content Water Content Peroent Non- TyFe of No of Bean Charge maintained in Decaffein- Caffeine Coffee Oilation Solids Loss Beans 1 54 % 0.3787 % 2.5 % "Milds" (1.33%
2 55 % 1.0097 % 1.1 %
In accordance wlth the present lnventlon, there ls pro-vided a process for producing a decaffelnated vegetable mate-rial comprising contacting a liquid, water-immiscible fatty material with a caffeine-containing vegetable material, main-taining said fatty material and vegetable material in contactfor a period of time sufficient to transfer caffeine from said vegetable material into said fatty material, and separating the resultant, caffeine-laden fatty material from the decaf-feinated vegetable material.
By "fatty material" as the term is utilized herein, is meant any of the animal or vegetable fats or oils or admix-tures or fractions thereof which assume a liquid form within the temperature range -- discussed hereinafter -- useful for the removal of caffeine from a caffeine-containing composi-tion. These fatty materials are customarily composed essen-tially of esters of fatty acids -- usually glycerol esters --and may be utilized in either their native form or in those resultant from conventional treatments as are known in the art. Moreover, the fatty materials used should desirably be non-solvants for constituents of the vegetable material other than caffeine.
Thus, for example, the present fatty materials may be in either unsaturated or saturated fats or oils. Similarly, unre-fined or conventionally refined oils as well as oils with or without such normal additives as anti-oxidants and preserva-tives are all useful within the scope of the present invention.
10~1019Z
It ls preferred, however, that the fatty materlal be essen-tlally exempt of surfactants, elther naturally - present or added. These materlals may stabilize emulsions which form upon agitation of liquid compositions utilized in accordance with the present invention and therefore increase the diffi-culty of such processing steps as centrifugal separation as may be required.
The fatty materials of the present invention include commercial oils and fats and thus numerous examples are raa-dily available. Of these fatty materials, however, thosewhlch are edible are highly preferred because their utiliza-tion reduces the need for special care in separation from ve-getable materials which will be further processed as comestib-les.
These fatty materials are useful for effecting virtually any desired degree of decaffeination of a vegetable material.
Thus, although essentially complete caffeine removal is ordi-narily preferred, a lesser degree can also be provided upon consumer demand. In either event, however, a corresponding amount of caffeine will become available as a valuable, com-mercial by-product.
The fatty materials are utilized to extract caffeine from various vegetable materials, most commonly from coffee or tea. In order, however, for decaffeination to proceed rea-dily, it is desirable that there be water present. It is be-lieved that this requirement is due to the desirability of ~(.~(~192 providing the caffeine in an initially water-solubilized or partially water-solubilized form, so as to facilltate its availability to the fatty material decaffeination solvent.
This belief as to a mechanism by which the present invention may operate is not, however, intended to limit the scope of the present invention but rather is set forth merely as an attempt at explanation of what may be occurring incident thereto.
Caffeine-containing vegetable materials which may be de-caffeinated in accordance with the present invention are mostsuitably provided in either aqueous liquid or solid form.
Where a solid form is employed, water should still be present, although it may be bound within the solid. Accordingly, aqueous solutions of vegetable material and vegetable materials having a substantial moisture content are preferred compositions for decaffeination in accordance with the present lnvention.
Aqueous extracts of tea or roast ground coffee are well-known and may be produced by means conventional in the art.
Because these extracts are themselves eventually converted into beverage products, however, they should ordinarily be treated in a manner so as to minimize exposure to conditions which might result in loss and/or degradation of valuable flavour constituents. One particular class of constituents of these brews -- the so-called volatiles or aromatics -- is particularly sensitive in this regard.
Accordingly, they are preferably removed early during processing and recombined with the more stable constituents only at or near the end of the beverage production cycle.
This removal and preservation of the volatile or aroma-tic constituents of vegetable materials may be accomplished by means well-known in the art. Thus, for example, it is con-ventional to subject aqueous extracts to stripping with steam, through which technique an aqueous condensate containing the aromatic and volatile constituents is readily obtained. Such isolates are then preserved under conditions of low tempera-ture until such time as they may be recombined with the pro-cessed vegetable material constituents, for example, by ad-mixture therewith immediately preparatory to drying or through application to the dried material itself followed by a short, secondary drying sequence. Accordingly, where aqueous extracts are decaffeinated with the fatty materials, the aqueous solu-tion of vegetable material is pr~ferably free of its customary volatile constituents.
Another liquid vegetable material which may be decaffei-nated in accordance with the present invention comprises an aqueous extract of the vegetable material, which has been formed specifically for the purpose of decaffeination and will not constitute any portion of the eventual beverage pro-duct. This embodiment of the present invention is most sui-table for vegetable materials such as coffee which normally require roasting or some other treatment to form many of their desired beverage constituents.
~0~92 Exemplary of thls embodiment of the present inventlon i8 an aqueous extract of green coffee beans. Such beans may be extracted with water so as to remove their caffeine content.
The resultant extract, however, contalns relatively few of the normal coffee beverage constituents inasmuch as these water-soluble constituents are largely produced only upon subsequent roasting of the beans.
The formation of this extract is fairly simple. All that is requlred is that the green beans be contacted with a weight of water sufficient for dissolving their caffeine content, the beans normally containing about 2 to 3 weight percent caffelne depending on thelr origin. Ordinarily, dissolution is accom-plished by counter-current flow of beans and water; however, thls step can be effected simply by slurrying the beans in water or any equivalent contact therebetween for a perlod of time -- usually 10 to 60 minutes -- sufficient to allow the desired degree of decaffeination.
Even where green beans are extracted with water, however, some valuable beverage constituents may also be removed to the aqueous phase. One technique by which the avoidance of any sub-stantial loss of these desired constituents has been insured is through closed, cyclic circulation of the aqueous extraction medium. Pursuant to this technique, the aqueous medium rapidly obtains its maximum concentration of the various water-soluble constituents, including caffeine, of green beans. Upon subse-quent selective removal of the caffeine from the medium, there 10!~01~2 is obtained a recyclable aqueous extraction medium which ra-pidly approaches dynamic equilibrium with respect to those water-soluble constituents of green beans which are not re-moved by decaffeination of the medium.
With such a dynamic equilibrium in effect, the recycled caffeine-free extraction medium will -- upon recontact with green coffee beans -- remove essentially only caffeine there-from. Thus, within a short time, a system may be obtained whereby essentially only caffeine is removed from the green beans.
Both, the recirculating extraction medium and the aqueous extract discussed more completely above all essentially aqueous solutions which contain both caffeine and various water-soluble vegetable material constituents. Accordingly, the present tech-nique of treating liquid vegetable materials with fatty mate-rial to remove caffeine therefrom may be applied to each in much the same manner. Thus, a liquid vegetable material is ad-mixed with a suitable volume of a liquid water-immiscible fat-ty material, maintained in admixture therewith until caffeine has migrated into the fatty material, and then separated with a corresponding decrease in its caffeine content. These steps may be accomplished quite simply, because the fact that both phases are liquid permits easy and thorough admixture under agitation, while the immiscibility of the two phases -- aqueous and fatty -- allows substantially complete separation by many known techniques, including decantation.
l(!~iO~
Of ma~or lmportance for the efflclency of decaffelna-tlon are the caffeine solubillty characterlstlcs of the fatty materlal. These propertles are dependent upon the particular materlal selected and the temperature durlng admlxture wlth the liquid vegetable material. Thls effect may be discussed ln terms of the distribution coefficient for caffelne between equal volumes of the fatty and aqueous phases durlng admlx-ture and at equilibrium. More particularly, the afflnity of the fatty material for caffeine is defined by the relation-shlp:
Distrlbution coefficient = caffeine concentration in fatty phasecaffeine concentration in aqueous phase for any glven temperature. Clearly then, higher dlstribution co-efficients evidence a superior ability to effect decaffeination.
In Table I which follows, exemplary data for various fatty materials at different temperatures are provided. The data re-flect the equilibrium achieved by single admixtures of volumes of fatty material and aqueous caffeine solutions. It should be understood that the fatty materials actually utilized are only representative commercial products. Thus, depending on the par-ticular history of a given material, some variation in the dis-tribution coefficient would be expected. With this data and the additional description provided herein, however, the characte-ristics and optimum conditions of use for other fatty materials within the scope of the present invention may easily be deter-mined.
_ g _ TABLE I
SOLUBILITY CHARACTERISTICS OF FATTY MATERIALS
Fatty Material Temperature Caffeine Distribution Coeffi-cient for Equal Volumes of _ Aqueous and Fattv Phases Safflower Oil 20 C .064 10 C .067 Soy Bean Oil 20 C .064 10 C .05g Corn Oil 20 C .064 15 C .064 10 C .071 5 C .085 Peanut Oil 10 C .067 Coffee Oil 23 C .140 Triolein (oleic acid ester of glycerol) 23 C .085 Olive Oil 23 C .076 Lard 65 C .197 The time of contact between fatty and vegetable phases is relatively unimportant. Only a few minutes are required for approaching the equilibrium degree. The optimum tempera-ture for decaffeination with any particular fatty material within the scope of the present invention hcwever should be determined prior to utilization. Exemplary data are reflected in Table I, but additional determinations may be made by well-known techniques and thus this aspect of the present invention may be ascertained by simple experimentation after selection of the particular fatty material to be utilized.
1~019Z
In determining the optlmum temperature, the partlcular materlals lnvolved place llmlts on the degree of deslrable varlation. Thus, the freezlng polnt of the aqueous vegetable material and the solidlfication point of the fatty material define the lower limit for useful temperatures. At the other end of the range, the degradation to flavour whlch may result upon exposure of flavour and aroma constltuents to hlgher tem-perature should also be avolded. Normally, however, decaffel-natlon can be effected within the range of from 0 to 50 C, wlth from 10 to 30 C being preferred for aqueous extracts.
Where these constituents are essentlally absent, stlll hlgher temperatures, up to the lnstability point for the particular vegetable material remain useful.
Once a particular fatty material and temperature for the decaffeination step have been selected, there remains the con-sideration of the desired degree of decaffelnatlon. This is usually controlled, at least partly through the ratlo of vege-table to fatty materials. Ordinarily, a ratlo of fatty mate-rial to aqueous vegetable materlal of about 20 : 1 will achleve only partial decaffeination in a single contacting sequence.
Thus, for example, at that ratlo, dlstrlbutlon coefficients of .035 and .085 yield about 40 % and 65 % decaffeinatlon respec-tlvely. Increases in the ratlo of fatty to vegetable materlal wlll, of course, lncrease thls degree of deoaffeination just as lower ratios decrease it.
Additionally, however, the means through which contactlng ~Ol~Z
wlth fatty materlal ls accompllshed affects the degree of de-caffelnatlon. Decaffelnatlon can occur as prevlously descrlbed, through a one-step decaffelnatlon sequence includlng contact-lng a partlcular welght of fatty materlal wlth a partlcular welght of aqueous extract, malntalnlng such materlals ln con-tact for a perlod sufflcient to approach or reach the caffeine dlstrlbutlon equlllbrlum, and then separatlng the extract. The efflclency of decaffelnation may however be increased by ln-creasing the number of steps. Accordlngly, in a preferred em-bodiment of the present lnventlon, decaffelnatlon i8 performedln a multl-step sequence, whereln the vegetable materlal is contaoted wlth successlve allquots of the fatty materlal untll the deslred degree of decaffelnation has been reached.
Thls preferred embodiment may most slmply be followed by successlvely contactlng the caffelne-contalning composltlon wlth allquots of a partlcular fatty materlal, malntalnlng the fatty and aqueous phases ln contact for a perlod of tlme suf-flclent to effect a substantial transfer of caffeine lnto the fat~y materlal (such a transfer ordlnarily belng in an amount greater than about 70 % of the equlllbrium dlstributlon there-ln), separating the aqueous and fatty phases and then repeat-lng thls sequence of steps wlth additlonal al$quots of caffelne-free fatty materlal.
Stlll another form of this preferred embodiment comprlses counter-current decaffeination. Therein, an initially caffelne-free fatty materlal is passed through consecutive volumes of :103~)~9~
vegetable material which are arrayed in reverse order by caffelne content. Thus, the fresh fatty material flrst con-tacts the most decaffeinated vegetable material volumes, and then those of higher caffeine content. During this process embodiment, when the first vegetable material volume reaches the desired degree of decaffeination, it is simply by-passed while a new volume -- having the highest caffeine content --is connected down-stream, to maintain a constant number of vo-lumes on stream and a proper order of contact with the fatty material.
It is additionally noted that aqueous solutions or ex-tracts of vegetable material may contain, for example, from 2 to 60 % soluble solids by total weight. Ordinarily, however, it is preferred that the solutions to be decaffeinated have a soluble solids concentration of from 10 to 50 %, preparatory to contacting with the fatty material caffeine solvent. Such concentrations are preferred for the purpose of minimizing the subsequent volumes of liquids which may be utilized in the de-caffeination sequence, as well as for the purpose of reducing the quantity of water which must eventually be removed from a brew or extract which is to be dried to solid form.
Concentration may be obtained through techniques well known to the prior art. Again, because the aqueous extract will eventually provide the dried beverage product, it is de-sirable that such concentration be obtained under conditionswhich will minimize the possibility of adverse effect on fla-vour. Accordingly, lt ls preferred that technlques such aslow pressure evaporatlon or freeze concentratlon, which avold exposlng the brew to higher temperature for any sub-stantial period of tlme, be utilized.
The present invention also includes utilization of a fatty material for direct decaffeination of solid vegetable materials. Exemplary of such solids are green coffee beans which may be provlded in ground, crushed and, most desirably, whole form. Roast coffee beans may also be utilized; however volatiles should first be removed to avoid undue loss of va-luable beverage constituents. Consequently, the decaffeination of whole green beans is most preferred and the following dis-cussion of this embodiment is particularly directed thereto, although other vegetable materials may be treated in similar manner.
Use of solid vegetable materials is a particularly pre-ferred embodiment of the present invention inasmuch as it ob-viates certain disadvantages of dealing with aqueous solutions of vegetable material. Thus, the separation of the fatty mate-rial from the caffeine-containing composition is facilitated by the fact that, while the fatty material remains liquid, the vegetable material is in solid form. Separation of the beans and fatty material may even conveniently be effected by simple drainage of the beans and, where centrifugal force is utilized to facilitate this separation, fairly simple machinery is ade-quate.
~0~0192 Further, in the separatlon of green coffee beans from a liquid fatty material, the degree of separation may be es-sentially 100 %. Whereas even the most sophisticated of immis-cible liquid separations may result in some retainment of one liquid in the other, no such problem is encountered here. Once most of the fatty material has been separated from the beans, a secondary physlcal purification step, such as dlrection of a burst of steam through the beans, permlts essentially 100 %
separation of retained fatty material. Moreover, even this additional step may be rendered unnecessary. Because of the post-decaffeination roasting and extractive processing of the beans, where a substantially flavourless fatty material is uti-lized, little if any effect upon the flavour of the eventual beverage product will result even if separation is incomplete.
In order to be in a form readily susceptible to caffeine removal, green coffee beans should contain some moisture. The beans ordinarily naturally contain from 8 to 10 % moisture, although higher amounts, of at least about 20 ~ by total weight, are preferred. The upper limit of moisture content, however, is more variable. Decaffeination of a caffeine-containing composi-tion comprising green beans is desirably performed in the ab-sence of free liquid water, so as to avoid the separation pro-blems incident to an admixture of liquids and the possible loss of valuable vegetable material constituents solubilized in that water. Accordingly, in this embodiment of the present invention, it is preferred that the green beans contain between about 20 , and 60 %, most preferably between about 40 and 60 %, water by total weight.
The incorporatlon of water into green beans is easily accomplished. Thus, for example, the beans may simply be im-mersed in water and there maintained for several hours, untilthey have absorbed the desired amount of moisture. Thereafter, they may easily be separated from the excess water, for exam-ple, by centrifugation. Through the use of heat and/or pres-sure, this incorporation or "swelling" of the beans may be accelerated. Thus, for example, where beans are immersed in water at a temperature of about 80 to 90 C, they achieve the desired moisture content much more quickly. Also, upon being subjected to steam at about 2 atmospheres, even less tlme --normally about 1 to 30 minutes -- is sufficient to reach the desired moisture content.
Once the beans have been swollen to an appropriate mois-ture content, they are placed in a bath or stream of fatty ma-terial until the desired degree of decaffeination has been achieved. Here, the time of admixture becomes significant :
transfer of caffeine from the beans is much slower than from dilute solution. Accordingly, it is desirable that periods of at least 30 minutes, with longer periods for more complete de-grees of decaffeination, be permitted for this step.
In processes leading to high degrees of decaffeination, it is also important to ensure that the moisture content of the swollen beans does not significantly decrease during treat-; - 16 -lQ~:)19Z
ment. Contact between swollen beans and fatty material can result in lower moisture contents due to loss of water from the beans to the fatty material. Where this decrease brings the beans to a moisture content below the preferred 40 to 60 % range, there occurs a corresponding decrease in the ef-ficlency of decaffeination.
It is therefore preferred that the fatty material uti-lized for decaffeination contain a small amount of water.
From 0.9 to 1.2 %, most desirably about 1.0 %, of water by weight of fatty material is ordinarily utilized in this pre-ferred embodiment of this invention. This amount acts to maintain in equilibrium the amount of water present in the beans and the fatty material, so that during contacting there is no net migration of water from the beans to the fatty phase, nor vice-versa. On the other hand, it prevents excessive remo-val of water from the beans, and on the other it minimizes the total amount of water present during decaffeination, thereby avoiding undue loss of non-caffeine, water-soluble bean con-stituents.
Again, the use of multi-step as opposed to single-step contact of fatty material with the vegetable material may be practiced in the manner previously described. Thus co-current and, more preferably, counter-current extraction with fatty material are desirable embodiments of the present invention.
One aspect by which the decaffeination of swollen green beans differs substantially from decaffeination of aqueous lQ~3019Z
caffelne-contalnlng solutlons lies ln the effect of tempera-ture upon the efficlency of decaffelnatlon. As previously no-ted, where decaffeination involves the contacting of fatty ma-terial with an aqueous caffeine-containing solution, differen-ces in temperature during such contact~ng do not have a largeeffect upon the efficlency of decaffelnatlon. In treating so-lid beans, however, increases in the prevaillng temperature for decaffelnation may dramatically increase the rate of caf-feine removal.
Accordingly, to achieve maximum efficiency of caffeine removal, decaffeination of beans is preferably carried out at as high a temperature as is practicable. Degradation of fatty materials customarily occurs at or around a temperature of about 150 C, and therefore this temperature usually repre-sents a practical maximum limit for decaffeination. Also, pro-longed contact times at very high temperatures may produce some degradation of flavour constituents. Accordingly, it is prefer-red that the decaffeination of green beans be performed within the temperature range of from about 50 to 120 C.
A further aspect of the present invention involves rege-nerating caffeine-containing fatty material so as to permit reuse thereof in the decaffeination process. This is most ef-ficiently achieved by contacting the separated caffeine-con-talning fatty material with water, permitting the transfer of the caffeine into aqueous phase, and then separating the fatty material to permit its recycle for further decaffeination. In large measure, the regeneration sequence reverses the steps already described above with respect to decaffeinatlon. In addition, however, it readily permits isolation of the caf-feine from the regenerate aqueous phase.
For regeneration of the fatty material, the efficiency of caffelne removal to aqueous phase is again governed by the same parameters of temperature, the caffeine distribution co-efficient of the particular fatty material, and the weight ratio of fatty material to water as discussed above with res-pect to the separation of caffeine from an aqueous solution of vegetable material.
Because flavour degradation is not a serious problem du-ring regeneration, as constituents of the final product are not present, the temperature during regeneration may be raised to improve the efficiency of caffeine transfer to the aqueous phase. Thus where, with increasing temperature, the solubility of caffeine in water increases more rapidly than in the fatty material, it is advantageous to effect regeneration at a tem-perature up to 100 C (and even higher where pressure is uti-lized to avoid evaporation). If on the other hand, lower tem-peratures favour this transfer then they should be employed.
Also, because it is here desired to transfer caffeine from the fatty material to an aqueous phase, the relatively greater solubility of caffeine in water permits the utiliza-tion of low fatty to aqueous phase ratios, even for substan-Z
tially complete transfer. Additionally, where lt is desired further to minlmize the amounts of water utlllzed in regene-ration of the fatty material, a multi-step regeneratlon se-quence comprising co-current or counter-current extraction of fatty material with water may be utilized in the same manner as has already been described hereinabove so as to facilitate the efficient regeneration of the fatty material.
Incident to regeneration of the fatty material through removal of caffeine with water, it has been discovered that the separated fatty material can contain -- even when separa-tion of these immisclble liquids is accomplished through such normally efficient means as centrifugal separation -- about 1 % by weight of water. This water is desirably removed from the fatty material before recontacting with vegetable mate-rial so as to avoid dilution of liquid vegetable materials.Removal of the entrained water in the fatty material can be accomplished by such means as a flash distillation under va-cuum conditions or equivalent known techniques.
As previously described, certain preferred embodiments of this invention relating to decaffeination of solid vege-table materials rely upon utilizing a fatty material contai-ning a small amount of water. In the practice of these embo-diments, the dilution factor becomes negligible. Therefore, the regenerated fatty material containing entrained water may be used directly for further decaffeination. Alternatively, its aqueous content may be adjusted -- for example, by adding lO9(~19Z
water or by partlal strlpplng -- as requlred to brlng lt to an optlmum water content.
Even where the presence of water ln the fatty material is desired, however it ls preferred to remove the entrained water and then add the desired amount of water to dry fatty material. This sequence of steps ensures an optlmum water content and avolds the difficulties and/or interruptlons re-quired for monitoring the entrained water content of regene-rated fatty materlal and then adjusting lt, as desired.
The followlng examples are lllustrative of the present inventlon. Unless otherwise noted, the percentages are on a weight basis.
An aqueous extract of roast ground coffee beans is stripped with steam to remove volatiles. 10 kilograms of the stripped extract, at a soluble solids concentration of 19 %
and a temperature of 22 C, are then added to 179 kilograms of corn oil at 60 C. The resultant admixture is agitated for 30 minutes and then passed through a centrifugal separa-tor at a rate of 3.16 kilograms per minute. The brew, whichis separated from the oil in the centrifuge, has a 51 ~ de-gree of decaffeination.
By repeating this treatment of the brew with additional corn oll, the degree of decaffeination is successively in-creased until essentially complete caffelne removal is effec-ted.
105~01~2 A tea extract having a soluble solids concentration of 27.6 % and a temperature of 22 C is mixed with corn oil in a volume ratio of 1 : 20, respectively, and maintained under agitation for 10 minutes. The admixture is then subjected to centrifugal separation to yield a tea extract exhibiting 63 %
decaffeination. Again retreatment affords a means for achiev-ing any greater desired degree of decaffeination.
ExAMæLE 3 Green coffee beans are decaffeinated utilizing a recir-culating aqueous medium which has reached an equilibrium so-luble solids concentration of 29 % and is at a temperature of 22 C. Decaffeination is performed by passing the aqueous me-dium in counter-current through a column of green beans, with essentially caffeine-free beans being removed from the column at one end and natural green beans added at the other. Within the circulating aqueous system, and at a point removed from the column, aqueous medium is diverted through a centrifugal extractor to which coffee oil at 50 C, in a ratio of 21 : 1 to the medium, is added for removal of caffeine from the aqueous extract. Heat exchangers in the system are used to maintain the temperatures of these two liquids essentially as indicated.
With a single pass of the medium and oil through the cen-trifuge, over one-third of the caffeine in the medium is re-moved. A second pass of the medium and a further equal aliquot 10~
of oil increases the decaffeinatlon of the medlum to over 60 %.
After roastlng, grlndlng and extracting separate samples of decaffelnated beans obtalned after the slngle and second pas-ses, lt ls found that both sample aqueous extracts are essen-tlally caffelne-free.
Green coffee beans are subjected to steam at 110 C untll they reach a molsture content of 45 ~ by total weight, and 10 kg aliquots are placed lnto separate extraction chambers. Each of the allquots is decaffeinated for four hours at 95 C wlth corn oil whlch ls passed through the chambers at a rate of 1.1 kg/mlnute.
In one Trial, "A", oil is passed through only one chamber.
Thereafter it is regenerated by extraction wlth water to remove lts caffeine content, the water is removed, and the oil is then recirculated to maintain a continuous flow of caffeine-free corn oll to swollen beans in the chamber.
In a second Trial, "B", four chambers are connected in se-ries so that the corn oil flows through each. Regeneration and recirculation of the oil is accomplished only after it has pas-sed through all four chambers. One chamber - the first contac-ted by oil - is removed each hour and a new chamber is added at the downstream end. In this manner, and after a start-up pe-riod of 6 hours a system is achieved wherein the four chambers contaln beans of varying caffeine content by virtue of the fact )l9Z
that they have been subjected to different duratlons of on-stream oil decaffeination.
The caffeine contents of beans from Trial "A" and from a chamber which has passed through all four stages of Trial "B" after start-up were analyzed. Despite the fact that each of these beans had been decaffeinated under essentially the same physical conditions, their respective degrees of decaf-feination are markedly different. Thus while the beans of Trial "A" exhibit 52 % decaffeination, those of Trial "B" ex-hibit 92 %. It is therefore evident that multi-step extraction substantially increases the efficiency of decaffeination.
An aqueous extract of roast ground coffee beans is strip-ped with steam to remove volatiles. 200 grams of the stripped brew having a soluble solids concentration of 18.4 % are then admixed with 2 kg of safflower oil and agitated for 30 minutes at 20 C. This admixture was then centrifuged to break the emulsion and the brew separated by decantation. The separated brew exhibits a 56 % degree of decaffeination.
The process of Example 5 is repeated with the change that 2 kg of soy bean oil are substituted for the safflower oil. After separation, the brew exhibits a 56 % degree of de-caffeination.
()192 The process of Example 5 is repeated substltuting 2 kg of peanut oil for the safflower oil. Additionally, the brew and oil are maintained at 10 C - instead of 20 C - through-out the process. The separated brew exhibits a 56 % degree ofdecaffeination.
Green coffee beans are decaffeinated with coffee oil in a four-chamber countercurrent extraction zone ln the manner described for Trial "B" of Example 4. Each chamber, or cell, contains 6.8 kg of beans by dry weight. The oil is maintained at 105 C and extraction is performed over a total extraction period of 6 hours (1.5 hours for each cycle). A total oil to bean weight ratio of 120 : 1 is utilized.
After each pass of the recirculating oil through all four chambers of the extraction zone, the oil regenerated by aqueous extraction for caffeine and then is stripped to remove its aqueous content. A predetermined measure of water is ad-mixed with the oil preparatory to its recirculation.
, ~ ~
Utilizing the foregoing procedure, five different Trials are made. These Trials differ essentially in the addition of varying amounts of water to stripped, caffeine-free fatty ma-terial. Data for steady-state conditions of operation of each Trial are as follows:
lO9015~Z
Tri~l Water Content Water Content Peroent Non- TyFe of No of Bean Charge maintained in Decaffein- Caffeine Coffee Oilation Solids Loss Beans 1 54 % 0.3787 % 2.5 % "Milds" (1.33%
2 55 % 1.0097 % 1.1 %
3 55 % 1.0097 % 1.1 ~ ll ¦ 4 ¦ 5 ~ ¦ 0.75¦ 69 ~ ¦ 2.4 ~ ¦~Rnb ~ta 57 % 1.2097 % 5.2 % "
This data indicates that proper moisture contents permit optimum decaffeination with minimal loss of non-caffeine bean constituents. The efficiency of decaffeination decreases where the concentration of water present in the fatty material during decaffeination decreases. It is also shown that, although the efficiency of decaffeination remains high at higher aqueous con-tents for the fatty material, the high level of water present in the system results in an increase loss of non-caffeine solubles from the beans.
This data indicates that proper moisture contents permit optimum decaffeination with minimal loss of non-caffeine bean constituents. The efficiency of decaffeination decreases where the concentration of water present in the fatty material during decaffeination decreases. It is also shown that, although the efficiency of decaffeination remains high at higher aqueous con-tents for the fatty material, the high level of water present in the system results in an increase loss of non-caffeine solubles from the beans.
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing a decaffeinated vegetable material comprising contacting a liquid, water-immiscible fatty material which is edible and a non-solvent for non-caffeine ingredients with a caffeine-containing vegetable material selected from an aqueous extract of tea and coffee, maintaining said fatty material and vegetable material in contact for a period of time sufficient to transfer caffeine from said vegetable material into said fatty material, and separating the resultant, caffeine-laden fatty material from the de-caffeinated vegetable material.
2. The process of Claim 1, wherein the caffeine-containing vegetable material comprises an aqueous extract of roast ground coffee.
3. The process of Claim 1, wherein prior to contacting the aqueous extract with the fatty material, volatiles are separated from said extract.
4. The process of Claim 1, wherein the caffeine-containing vegetable material comprises an aqueous extract of green coffee beans.
5. The process of Claim 4, wherein the decaffeinated aqueous extract of green coffee beans, following contact with fatty material, is recycled for further contact with green coffee beans.
6. The process of any one of Claims 2 to 4, wherein the aqueous extract has a soluble solids concentration of 2 to 60% by total weight.
7. The process of any one of Claims 2 to 4, wherein said aqueous extract has a soluble solids concentration of 10 to 50% by weight.
8. The process of any one of Claims 2 to 4, wherein the aqueous extract and fatty material are contacted and maintained at a temperature between
9. The process of Claim 1, wherein the caffeine-containing vegetable material is green or roasted coffee beans.
10. The process of Claim 9, wherein volatiles are separated from said roast coffee beans prior to decaffeination.
11. The process of Claim 9, wherein prior to contact of the beans with fatty material, said beans are swollen with water to a total moisture contact of from 20 to 60% by weight.
12. The process of any one of Claims 9 to 11, wherein the beans and fatty material are contacted and maintained at a temperature between 30° and 150 °C.
13. The process of any one of Claims 9 to 11, wherein the fatty material utilized to contact the beans has a moisture content which is substantially in equilibrium with the moisture content of the beans.
14. The process of Claim 2, wherein the separated caffeine-laden fatty material is contacted with water to transfer substantially all the caffeine contained therein into aqueous solution, the caffeine-laden aqueous solution is separated from said fatty material and the caf-feine-free fatty material is recycled for further contact with caffeine-containing vegetable material.
15. The process of Claim 4, wherein the separated caffeine-laden fatty material is contacted with water to transfer substantially all the caffeine contained therein into aqueous solution, the caffeine-laden aqueous solution is separated from said fatty material and the caffeine-free fatty material is recycled for further contact with caffeine-containing vegetable material.
16. The process of Claim 9, wherein the separated caffeine-laden fatty material is contacted with water to transfer substantially all the caffeine contained therein into aqueous solution, the caffeine-laden aqueous solution is separated from said fatty material and the caffeine-free fatty material is recycled for further contact with caffeine-containing vegetable material.
17. The process of any one of Claims 14 to 16, wherein prior to recycle of the caffeine-free fatty material, the moist-ure content of said fatty material is adjusted to a level which is substantially in equilibrium with the moisture content of the caffeine-containing vegetable material.
18. The process according to any one of Claims 2, 4 and 9, wherein the fatty material is safflower oil, soy bean oil, corn oil, peanut oil, coffee oil, triolein or lard.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52787074A | 1974-11-27 | 1974-11-27 | |
| US527870 | 1974-11-27 | ||
| US60571775A | 1975-08-18 | 1975-08-18 | |
| US605717 | 1975-08-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1090192A true CA1090192A (en) | 1980-11-25 |
Family
ID=27062536
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA239,458A Expired CA1090192A (en) | 1974-11-27 | 1975-11-12 | Decaffeination process |
Country Status (26)
| Country | Link |
|---|---|
| JP (1) | JPS5940414B2 (en) |
| AR (1) | AR204886A1 (en) |
| AT (1) | AT349871B (en) |
| BR (1) | BR7507897A (en) |
| CA (1) | CA1090192A (en) |
| CH (1) | CH604552A5 (en) |
| CS (1) | CS188981B2 (en) |
| DD (1) | DD121266A5 (en) |
| DE (1) | DE2548916C2 (en) |
| DK (1) | DK151364C (en) |
| ES (1) | ES442974A1 (en) |
| FR (1) | FR2292433A1 (en) |
| GB (1) | GB1516208A (en) |
| IE (1) | IE41949B1 (en) |
| IL (1) | IL48450A (en) |
| IN (1) | IN141265B (en) |
| IT (1) | IT1050317B (en) |
| LU (1) | LU73863A1 (en) |
| MX (1) | MX3083E (en) |
| NL (1) | NL186291C (en) |
| NO (1) | NO159472C (en) |
| OA (1) | OA05175A (en) |
| PH (1) | PH14577A (en) |
| PL (1) | PL96827B1 (en) |
| SE (1) | SE445964B (en) |
| YU (1) | YU36429B (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1096229A (en) * | 1976-05-27 | 1981-02-24 | Geoffrey Margolis | Decaffeination process |
| US4113886A (en) * | 1977-09-28 | 1978-09-12 | General Foods Corporation | Membrane decaffeination |
| US4315036A (en) * | 1978-01-12 | 1982-02-09 | Societe D'assistance Technique Pour Produits Nestle S.A. | Process for decaffeinating tea |
| US4237288A (en) * | 1979-05-17 | 1980-12-02 | Societe D'assistance Technique Pour Produits Nestle S.A. | Decaffeination of fatty materials |
| CH638379A5 (en) * | 1979-06-14 | 1983-09-30 | Nestle Sa | Method for processing coffee beans |
| US4324840A (en) * | 1980-06-16 | 1982-04-13 | General Foods Corporation | Adsorption decaffeination |
| US4545998A (en) * | 1980-09-30 | 1985-10-08 | General Foods Corporation | Multi-phase liquid solvent decaffeination |
| US4446162A (en) * | 1982-03-31 | 1984-05-01 | General Foods Corporation | Decaffeination of a coffee extract |
| NL8203139A (en) * | 1982-08-09 | 1984-03-01 | Douwe Egberts Tabaksfab | METHOD FOR DECAFFINING GREEN COFFEE. |
| US4430353A (en) | 1982-11-08 | 1984-02-07 | General Foods Corporation | Low-grade coffee |
| US4659577A (en) * | 1984-09-27 | 1987-04-21 | General Foods Corporation | Method for the decaffeination of roasted coffee extracts |
| GB2286108A (en) * | 1994-02-01 | 1995-08-09 | Surinder Pal Grewal | A method of preparing coffee beans |
| JP6143808B2 (en) * | 2015-05-28 | 2017-06-07 | 曽田香料株式会社 | Extraction method of solute components in aqueous solution |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH166486A (en) * | 1933-02-27 | 1934-01-15 | Max Brunner & Co | Process for the production of caffeine-free coffee by removing the caffeine with neutral tasteless and odorless solvents. |
| US3669679A (en) * | 1970-04-24 | 1972-06-13 | Gen Foods Corp | Green bean decaffeination employing fluorinated hydrocarbons |
| US3682648A (en) * | 1970-05-27 | 1972-08-08 | Gen Foods Corp | Green coffee decaffeination using edible ester solutions |
| DE2127642C3 (en) * | 1971-06-03 | 1975-10-16 | Studiengesellschaft Kohle Mbh, 4330 Muelheim | Process for making caffeine-free, full-flavored black tea |
| DE2357590C3 (en) * | 1973-11-19 | 1983-02-03 | Hag Ag, 2800 Bremen | Process for decaffeinating green coffee |
-
1975
- 1975-01-01 AR AR261352A patent/AR204886A1/en active
- 1975-10-31 DE DE2548916A patent/DE2548916C2/en not_active Expired
- 1975-11-07 GB GB46175/75A patent/GB1516208A/en not_active Expired
- 1975-11-11 IL IL48450A patent/IL48450A/en unknown
- 1975-11-11 CH CH1456075A patent/CH604552A5/xx not_active IP Right Cessation
- 1975-11-12 IN IN2101/CAL/1975A patent/IN141265B/en unknown
- 1975-11-12 CA CA239,458A patent/CA1090192A/en not_active Expired
- 1975-11-17 SE SE7512893A patent/SE445964B/en not_active IP Right Cessation
- 1975-11-18 CS CS757787A patent/CS188981B2/en unknown
- 1975-11-19 MX MX418975U patent/MX3083E/en unknown
- 1975-11-20 YU YU02941/75A patent/YU36429B/en unknown
- 1975-11-21 NO NO753925A patent/NO159472C/en unknown
- 1975-11-24 IE IE2560/75A patent/IE41949B1/en unknown
- 1975-11-24 PH PH17800A patent/PH14577A/en unknown
- 1975-11-24 DK DK528975A patent/DK151364C/en not_active IP Right Cessation
- 1975-11-25 LU LU73863A patent/LU73863A1/xx unknown
- 1975-11-25 JP JP50141068A patent/JPS5940414B2/en not_active Expired
- 1975-11-26 ES ES442974A patent/ES442974A1/en not_active Expired
- 1975-11-26 FR FR7536248A patent/FR2292433A1/en active Granted
- 1975-11-26 OA OA55676A patent/OA05175A/en unknown
- 1975-11-26 AT AT897675A patent/AT349871B/en not_active IP Right Cessation
- 1975-11-27 IT IT9746/75A patent/IT1050317B/en active
- 1975-11-27 NL NLAANVRAGE7513874,A patent/NL186291C/en not_active IP Right Cessation
- 1975-11-27 DD DD189738A patent/DD121266A5/xx unknown
- 1975-11-27 PL PL1975185049A patent/PL96827B1/en unknown
- 1975-11-27 BR BR7507897*A patent/BR7507897A/en unknown
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