Method of making a coca leaf flavor extract

A flavor extract is prepared by extraction of coca leaves to form a raw extract and treatment of the raw extract with an ion exchange resin to remove cocaine and ecgonine. The resulting flavor extract has excellent organolyptic properties.

BACKGROUND OF THE INVENTION 
The present invention relates to flavor extracts, methods of preparing the 
same and products incorporating the same. 
The leaves of coca plants contain particularly desirable flavor 
constituents which can be added to edible products such as colas and other 
beverages, foods and pharmaceutical preparations for oral administration. 
However, coca leaves also contain cocaine and ecgonine alkaloids which are 
potent addictive drugs. In order to produce a satisfactory flavor extract 
for use as an additive to foods and beverages and for use as a non-drug 
flavor additive in pharmaceuticals, the flavor constituents in the coca 
leaves must be extracted from the leaves and separated from these 
alkaloids. This is a formidable task. Whatever process is used should 
separate essentially all of the cocaine and ecgonine from the flavor 
constituents. Presence of these substances in a flavor extract is highly 
undesirable for reasons of health, and is prohibited by government 
regulations. The flavor constituents in the coca leaves include a complex 
mixture of numerous components susceptible to degradation or loss during 
processing. The separation of the cocaine and ecgonine from the flavors 
should be accomplished without substantial loss or degradation of useful 
flavor constituents. Moreover, many of the flavor constituents are soluble 
in the same solvents as the undesirable alkaloids. Attempts to prepare a 
satisfactory flavor extract from coca leaves by first treating the leaves 
with various organic solvents to remove the alkaloids and then extracting 
the flavors from the leaves have been unsuccessful because a substantial 
portion of the flavors are lost with the alkaloids in the solvent extract. 
Thus, prior to the present invention there have been significant unmet 
needs for improved methods of preparing flavor extracts from coca leaves, 
for improved flavor extracts made from coca leaves and for improved edible 
products containing such extracts. 
SUMMARY OF THE INVENTION 
The present invention addresses these needs. 
One aspect of the present invention provides methods of making flavor 
extracts. A method according to this aspect of the present invention 
desirably includes the steps of forming a raw extract of coca leaves 
including flavor constituents from the leaves together with alkaloids 
selected from the group consisting of cocaine, ecgonine and combinations 
thereof in a solvent. The method further includes the steps of contacting 
the raw extract with a cation exchange resin so that the exchange resin 
takes up these alkaloids from the raw extract and separating the resulting 
flavor extract from the resin. 
This aspect of the present invention incorporates the discovery that 
treatment of a coca leaf extract with cation exchange resins can separate 
the cocaine and ecgonine from the extract without substantially adversely 
affecting the flavors in the extract. Preferred processes according to 
this aspect of the present invention thus provide facile and effective 
ways of making flavor extracts having desirable taste and aroma. Preferred 
processes according to this aspect of the invention yield flavor extracts 
having no cocaine or ecgonine detectable by recognized tests for these 
substances, such as the Bohm's test described below. Moreover, the 
preferred processes can be performed economically and provide reliable 
separation of the cocaine and ecgonine from the extracts. 
Further aspects of the present invention include improved flavor extracts 
prepared by the aforementioned processes, improved edible products 
incorporating such extracts and improved methods of making edible 
products. 
These and other objects, features and advantages of the present invention 
will be more readily understood from the detailed description of the 
preferred embodiments set forth below. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A process according to one embodiment of the present invention utilizes 
coca leaves as a starting material. As used in this disclosure, the term 
"cocao" should be understood broadly as including plants of all species 
within the genus erythroxylon and erythroxylaceae. Preferably, the leaves 
used are leaves of erythroxylon coca, the plant commonly referred to as 
the "coca plant". Also, the coca leaves utilized may be mixed with other 
non-leafy portions of the plant such as stems, branches and the like. The 
leaves may be substantially as taken from the plant without prior 
treatment or else may be pre-treated by drying, fermentation, roasting or 
the like. The leaves desirably are ground or otherwise comminuted. The 
size range of the comminuted leaves is selected to facilitate extraction. 
Desirably, the leaves are comminuted to less than about 4 mesh, and more 
preferably, about 9-10 mesh U.S. Standard Sieve Size. 
The comminuted leaves are contacted with an extraction solvent so as to 
transfer flavors and the cocaine and ecgonine alkaloids from the 
comminuted leaves to the solvent, thereby forming a raw extract. As used 
in this disclosure, the terms "flavors" and "flavor constituents" should 
be understood as encompassing substances which are detectable by either or 
both of the human senses of smell and taste, i.e., as including substances 
which affect the aroma or taste of a product. The solvent desirably is 
selected from the group consisting of water, lower alcohols and 
combinations thereof. Solutions of water and ethanol are especially 
preferred. Desirably, the solvent contains between about 10% and about 90% 
ethanol, more desirably between about 20% and about 50% ethanol and most 
desirably about 20% ethanol by volume, the remainder being water. The 
water employed preferably is deionized or distilled water substantially 
free of ionic impurities. Desirably, the pH of the raw extract formed in 
this contacting step is less than 8, preferably between about 5 and about 
7 and most preferably about 5.5 to about 7.0. If necessary, the solvent 
and hence the resulting extract, may incorporate physiologically 
acceptable acids or bases. However, these are normally unnecessary where 
the more preferred ethanol/water solvents are employed inasmuch as the 
extract formed with these solvents typically has pH within the desired 
range. 
The leaves and solvent may be contacted in a discontinuous or batch process 
wherein the leaves are immersed in the solvent in an appropriate vessel 
and held for a predetermined contacting interval, desirably between about 
two hours and about forty-eight hours, more desirably between about four 
hours and about twenty-four hours and most desirably about fifteen hours. 
The contacting step may be performed at any temperature within the range 
from the freezing point of the solvent to its boiling point. Preferably, 
however, the contacting step is performed at about 15.degree. to about 
50.degree. C. and most preferably at about 20.degree. C. Following the 
contacting step, the comminuted leaves are mechanically separated from the 
raw extract by conventional methods such as filtration, centrifugation and 
the like. The step of contacting the leaves and solvent can be performed 
by percolation. Also, in place of separate batchwise contacting and 
separation steps, the contacting and separation steps can be performed in 
conventional continuous process equipment with cocurrent or countercurrent 
flow of leaves and solvent. Desirably, the ratio of leaves to solvent 
employed in this contacting operation is between about 0.045 and about 
0.27 w/v, i.e., about 0.045 to about 0.27 grams of leaves per mililiter of 
solvent. Preferably, the leaf:solvent ratio is about 0.133 w/v. Most 
preferably, the raw extract contains about 1% to about 5% solids by 
weight, and most preferably about 2% to about 3.5% solids by weight. 
After recovery of the raw extract, the same is contacted with a suitable 
cation exchange resin, desirably a sulfonic acid, carboxylic acid or 
phosphoric acid cation exchange resin and more desirably a sulfonic acid 
cation exchange resin. Particularly preferred sulfonic acid cation 
exchange resins incorporate the sulfonic acid moieties on a styrene 
structure crosslinked with divinylbenzene. Especially preferred cation 
exchange resins are sold under the registered trademarks AMBERLIGHT and 
DUOLITE by the Rohm and Haas Company of Philadelphia, Pa. Particularly 
preferred resins are those designated as AMBERLITE.RTM. IR-120, IR-132 and 
DUOLITE.RTM. C-225. The cation exchange resin prior to contact with the 
raw extract most preferably has exchangable H.sup.+ ions although resins 
having other exchangable cations such as sodium can be employed. 
The contacting and step desirably is performed by maintaining the resin in 
an elongated column or bed having an upstream end and a downstream end and 
passing raw extract into the column at the upstream end. The resulting 
flavor extract is recovered and separated from the resin at the downstream 
end of the column. In this procedure, the steps of contacting the raw 
extract with the resin and separating the resulting flavor extract are 
performed on a substantially continuous or semicontinuous flow through 
basis. The column may be mounted vertically or horizontally. With a 
vertically-extensive column, the upstream end may be either the top end or 
the bottom end of the column. Although passage through a column represents 
the preferred manner of contacting the raw extract with the ion exchange 
resin, other contacting techniques such as a batchwise process may be 
employed. 
The step of contacting the extract with the resin can be performed at any 
temperature between the freezing and boiling points of the extract. 
Desirably, however, this contacting step is performed at temperatures 
between about 15.degree. C. and about 50.degree. C. and most preferably at 
about 20.degree. C. Preferably, the pH of the extract during the 
contacting step is within the aforementioned preferred pH ranges, i.e., 
less than 8, preferably about 5 to about 7 and most preferably about 5.5 
to about 7.0. Ordinarily, no special pH adjustment or control measures are 
required to maintain the pH of the extract within this desired range. 
However, acid and/or alkali addition may be employed during the resin 
contacting step as required to maintain the pH within the desired range. 
The ratio of extract to resin employed in the contacting step, and the 
conditions controlling the duration of contact between extract and resin, 
such as resin column depth and diameter, extract flow rate and the like 
should be selected to permit substantially complete transfer of the 
cocaine and ecgonine alkaloids from the extract to the resin. Ordinarily, 
a given bed of ion exchange resin will become progressively more 
susceptible to breakthrough or appearance of the alkaloids in the effluent 
as the bed is used and some alkaloids have accumulated in the more 
upstream portions of the bed. The conditions needed to prevent 
breakthrough of the undesired alkaloids with any given bed will depend 
upon the depth or upstream to downstream extent of the bed, the 
concentration of the undesired alkaloids in the incoming extract supplied 
at the upstream end, the extract flow rate and the like. Desirably, the 
ion exchange resin bed is at least about twenty-four inches deep and has a 
ratio of depth or upstream to downstream extent to diameter or greatest 
dimension crosswise to the upstream to downstream extent of about 25 to 1 
or more. With the preferred ion exchange resin beds, the ratio of extract 
processed through the bed to the volume of resin in the bed may be about 5 
to 1 or more. That is, about 5 ml of extract may be processed through the 
bed for each ml of resin in the bed without breakthrough of the undesired 
alkaloids to the effluent extract. The used resin retains the cocaine and 
ecgonine recovered from the raw extract. The fully used bed may be 
regenerated by conventional techniques such as exposing the bed to a 
stream of flowing dilute hydrochloric or sulfuric acid under room 
temperature or higher temperatures so as to dislodge the cocaine and 
ecgonine and also degrade these substances. 
After treatment in the resin bed, the resulting flavor extract desirably 
contains no cocaine detectable by the Bohm's test, a standard wet chemical 
test for detection of cocaine and ecgonine. Bohm's test employs a reagent 
known as Mayer's reagent. Mayer's reagent is made by dissolving 0.68 grams 
of mercury chloride and 2.5 grams of potassium iodide in water sufficient 
to make 100 ml of the reagent solution. In the Bohm's test as referred to 
in this disclosure, 2 to 4 drops of Mayer's reagent and 2 to 3 drops of 
concentrated sulfuric acid are added to 2-5 ml of a liquid extract or 
solution to be tested. If the solution turns cloudy, cocaine, ecgonine or 
both are present. 
The flavor extract prepared as above can be further treated by conventional 
techniques for removing solvents from flavor extracts so as to yield a 
more concentrated extract. As is well known, these techniques include 
reverse osmosis, low temperature vacuum drying, freeze drying and the 
like, all of which tend to preserve volatile and/or unstable flavor and 
aroma ingredients. These processes can be continued to yield a flavor 
extract essentially free of solvent. Moreover, the flavor extract, either 
before or after solvent removal, can be combined with additional 
ingredients to yield a beverage concentrate and/or beverage extract. 
Desirably, a preservative such as sodium benzoate is added to the extract 
if the extract is to be stored for a prolonged period.

EXAMPLE I 
1500 grams of coca leaves from erythroxylon coca, taken from plants grown 
in several different areas, are mixed and ground to 9-10 mesh. The ground 
leaves are placed in a vessel and 11.25 liters of a solvent mixture 
consisting of 20% ethanol and 80% deionized water by volume are placed in 
the vessel along with the leaves, so that the solvent mixture entirely 
covers the ground leaves. The leaves are left to steep in the solvent 
mixture at room temperature, about 20.degree. C., for about fifteen hours. 
Separation of the liquid from the leaves by filtration yields eight liters 
of a raw extract containing 2.5% solids and having a pH of 5.72. The raw 
extract is passed through a column of DUOLITE.RTM. C-225 resin obtained 
from the Rohm and Haas Company of Philadelphia, Pa. The column of resin is 
approximately 5 cm in diameter and 1.6 meters long. The raw extract is 
passed through the column by gravity drainage at a rate of about 50-70 
ml/min. Seven liters of flavor extract are collected at the downstream end 
of the column. High performance liquid chromatography and gas liquid 
chromatography assays confirm that the flavor extract contains no cocaine 
or ecgonine detectable by these methods. The flavor extract contains 2.2% 
solids and has a pH of about 6.10. 
The flavor extract is subsequently blended with a conventional cola base, 
containing carbonated water, sweetener and carmel color. The resulting 
beverage has a pleasant, cola flavor note and aroma. 
EXAMPLE II 
The procedure of Example I is repeated. After the first steeping and 
filtration cycle, the ground leaves recovered by filtration are again 
extracted with a fresh batch of the same 20% ethanol/80% water solvent 
mixture, again with steeping for about fifteen hours at room temperature. 
Filtration yields a further charge of raw extract having a solids content 
of about 1.0%. This raw extract is passed through the same ionic column as 
the first raw extract from the first solvent contact step, so as to 
provide an additional volume of flavor extract. 
EXAMPLE III 
The procedure according to Example I is repeated several times, but using 
smaller batch sizes. In each case, 100 grams of ground coca leaves are 
steeped for about fifteen hours in 750 ml of a solvent mixture as 
specified in TABLE I below, the results are as indicated in the table. 
Each line in TABLE I designated by a letter represents a single sample, 
and includes data for that sample both before and after ion exchange 
treatment. In every case, the raw extract includes either cocaine or 
ecgonine as determined by the Bohm's test, whereas the flavor extract 
after ion exchange treatment has no detectable cocaine or ecgonine, based 
on the Bohm's test. 
TABLE I 
__________________________________________________________________________ 
FLAVOR EXTRACT AFTER ION 
RAW EXTRACT EXCHANGE TREATMENT 
SOLIDS FLAVOR (IN FLAVOR (IN 
SAMPLE 
SOLVENT pH % AROMA 
COLA BASE) 
AROMA COLA BASE) 
__________________________________________________________________________ 
A 50% ethanol 
6.65 
3.0 Good Good Good Good 
50% H.sub.2 O Cola Cola Cola Cola 
B Same as A + 
4.0 
4.3 Fair to 
Not tested 
Acceptable 
Acceptable 
1% phosphoric Poor 
acid 
C Same as A + 
9.30 
3.3 Poor Not tested 
Fair to Not tested 
1% soda ash Poor 
D 20% ethanol 
6.80 
2.4 Good Good Very Good 
Very Good 
80% water Cola Cola Cola Cola 
(Most preferred) 
E Same as D + 
3.90 
3.6 Fair to 
Not tested 
Fair to Not tested 
1% phosphoric Poor Poor 
acid 
F Same as D + 
9.10 
3.1 Fair to 
Not tested 
Fair to Not tested 
1% soda ash Poor Poor 
G H.sub.2 O + 1% 
3.75 
3.4 Fair to 
Not tested 
Fair to Not tested 
phosphoric acid Good Good 
Tea-like Tea-like 
__________________________________________________________________________ 
These results demonstrate that in every case the ion exchange resin 
treatment effectively removes the cocaine and ecgonine without adversely 
affecting the flavor of the raw extract. The results further demonstrate 
that the more preferred alcohol/water solvents and pH within the preferred 
ranges provide particularly good flavor extracts for applications where a 
cola-like flavor is desired. 
As will be appreciated, numerous variations and combinations of the 
features described above may be utilized without departing from the 
present invention as defined by the claims. Thus, the raw extract treated 
in the ion exchange resin contacting step of the process may be prepared 
from coca leaf ingredients recovered in various ways. It is possible, for 
example, to extract the ground coca leaves with one solvent to thereby 
recover a mixture of flavor ingredients and alkaloids, dry these 
ingredients and then subsequently prepare a raw extract for contact with 
the ion exchange resins by reconstitution in another solvent. As these and 
other variations and combinations of the features described above can be 
utilized without department from the present invention as defined by the 
claims, the foregoing description of the preferred embodiments should be 
taken by way of illustration rather than by way of limitation of the 
invention.