US 2766148 A
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Description (OCR text may contain errors)
2,766,148 @atented Oct. 9, 1956 TOBACCO Ralph Lawrence Rowland, Winston-Salem, N. C., assignor to R. J. Reynolds Tobacco Company, Winston- Salem, N. (3., a corporation of New Jersey No Drawing. Application July 26, 1954, Serial No. 445,894
13 Claims. (Cl. 13117) This invention relates to tobacco and has for an object the provision of a smoking tobacco product having improved aroma and flavor characteristics which become apparent during smoking.
Smoking tobacco as now prepared for use in cigarettes comprises essentially a blended mixture of various types of tobaccos which are desired to produce a characteristic flavor and aroma when the tobacco is smoked. Present day cigarette tobaccos normally comprise blends of (l) heat-cured tobaccos, which are sometimes known as fluecured, bright leaf or Virginia tobaccos, (2) air-cured tobaccos, which are sometimes known as burley or Kentucky and Maryland tobaccos, and (3) sun-cured tobaccos, which are known as Turkish or Oriental tobaccos. The relative proportions of these various types blended to produce a desired cigarette tobacco mixture depend in a lar e measure upon the characteristic flavor or aroma that is desired to be achieved when the tobacco is smoked. Also it is common practice to add various substances, such as flavoring materials and humectants, in order to provide other desired properties.
A further object of this invention is to provide a smoking tobacco which when smoked will have improved or enhanced flavor and odor characteristics which will be pleasing to the smoker.
A further object of this invention is the provision of a smoking tobacco having added thereto a compound or compounds which, when the tobacco is smoked, will liberate one or more organic acids imparting a selected and desired flavor and aroma to the smoke.
A still further object of this invention is the provision of a tobacco product having added thereto a substantially nonvolatile substance which in itself does not substantially change the flavor or aroma of the tobacco but which when burned on the tobacco will release to the smoke certain desired flavoror aroma-producing acids.
A still further object of this invention is the provision of a tobacco having added thereto an organic compound which, when the tobacco is smoked or burned, will li'oerate several types of flavoring acids whereby the desired improvement in the flavor and aroma of the smoke may be achieved.
A still further object of this invention is to provision of additives for tobacco which may be easily and simply prepared and which may be incorporated into the tobacco at any stage during the processing theretof.
A further object of this invention is the provision of a tobacco containing an additive which is a derivative of certain naturally occurring substances some of which substances may be related to compounds normally found in tobacco, said derivative being one which will release a flavor-producing acid when the tobacco is smoked.
Further and additional objects will appear from the following description and the appended claims.
In the copending application of Samuel OBrien Jones, Serial No. 445,891, filed July 26, 1954, it is disclosed that certain esters of flavor-producing acids when added to tobacco will, when smoked or burned with the tobacco,
release the acid or acids which latter impart a desired characteristic odor and/or flavor to the smoke, thereby contributing to the enjoyment of the smoker.
In accordance with the broad aspects of this invention, a smoking tobacco composition is provided which contains as an additive a small amount of an ester of a high molecular weight polyhydric compound selected from the group consisting of polysaccharides, conjugated saccharides and lignins, which ester, when smoked or burned with the tobacco, will release one or more organic flavoring acids. These acids, when present in the smoke in suitable concentrations, will impart characteristic and desirable flavor and aroma to the tobacco smoke, thus contributing to the enjoyment of the smoker. The ester additives of this invention are substantially nonvolatile under ordinary tobacco storage conditions and will remain dispersed throughout the tobacco until such time as it is smoked and, being nonvolatile, will remain in the burning area of the tobacco to permit the acid release to occur. Also the additives of this invention are relatively stable under the usual tobacco storage conditions; consequently the principal release of the flavoring acid or acids does not occur until the tobacco is smoked.
The polyhydric compounds which are esterified with the flavoring acid to produce the additives of this invention are related to those which are found in nature. They are high molecular weight compounds which may or may not be soluble in water. They include the polysaccharides having more than three monosaccharide units per molecule, the conjugated saccharides comprising condensation products of a saccharide or related compound (e. g. a uronic acid) and another compound, or lignins and their derivatives and related compounds. Polyhydric compounds that have been found to be particularly suitable are starch, cellulose, pectin and lignin. However, other related high molecular Weight polyhydric compounds may also be used, such as dextrins, inulins, glycogens, lichenins, hemicelluloses, pentosans, hexosans, natural gums and mucilages, glucosides, tannins, and the like.
The flavor-producing acids which are released by the esters in accordance with this invention are preferably those flavoring acids which will volatilize and will be carried by the smoke, such acids usually being the organic carboXylic acids having 3, 4, 5, 6, 7 or 8 carbon atoms, herein collectively referred to as those having from 3 to 8 carbon atoms. Representative acids are the saturated aliphatic fatty acids, such as propionic, n-butyric, isobutyric, n-valeric, isovaleric, Z-methylbutyric, ncaproic, 4-methylvaleric, 3-methylvaleric, 2,2-dimethylbutyric, Z-methylisovaleric, straight or branched chain heptoic, or straight or branched chain caprylic acids; the unsaturated aliphatic fatty acids, such as acrylic, crotonic, vinylacetic, 4-methyl-4-hexenoic and S-methylsorbic acids; the cycloalkane or cycloalkene aliphatic acids, such as cyclopentanecarboxylic, cyclohexanecarboXylic, cyclopentaneacetic or cyclohexaneacetic acids or the corresponding unsaturated cycloalkencs; the aromatic carboxylic acids, such as benzoic or toluic acids; and phenylacetic acid. Also the volatile derivatives of such acids, such as hydroxy acids or keto acids, may be'the acid compounds released to impart the desired odor or flavor to the smoke. It is preferred that the flavoring acid be an aliphatic or alicyclic saturated monocarboxylic acid of the fatty acid series having 4, 5 and 6 carbon atoms, herein collectively referred to as those having from 4 to 6 carbon atoms.
It will be apparent that the ester additive may be selected or prepared in such a manner that any one of the foregoing acids will be released during smoking. Also a single additive or mixture of additives may be selected and added to the tobacco so that a plurality of desired flavoring acids may be simultaneously liberated if desired, thus effecting a blend of the various types of aromas which has the characteristics of the several flavoring acids. Also, if desired, the several hydroxyl groups in the polyhydroxy compound may be esterified with one or more different flavoring acids or less than all of the hydroxyl groups may be esterified to produce the additive used in accordance with this invention. The specific flavor-producing acid or acids that are combined with the hydroxy compound to form the ester will depend upon the flavor and aroma desired in the tobacco smoke. As indicated above, the particular acid selected for the preparation of the ester is of consequence only in so far as the particular flavor contributed by that particular acid is important. Any of the flavor-prodnciug acids may be utilized and, as previously indicated, they generally comprise the saturated or unsaturated organic carboxylic acids containing from 3 to 8 carbon atoms, preferably the saturated aliphatic monocarboxylic acids having from 4 to 6 carbon atoms.
The additives contemplated by this invention may be incorporated into the tobacco in any desired manner. For example, solutions of the additive in a suitable solvent, such as alcohol, ethyl ether, acetone or the like, may be applied to the tobacco as by spraying or otherwise, hereafter the solvent is driven off as a vapor leaving the additive thoroughly incorporated with the tobacco. The additive may also be uniformly dispersed in water and applied in a like manner if desired. The incorporation cf the additive may take place at any time prior to the final packaging of the tobacco product. In the case of cigarette tobacco, it may be incorporated before or after blending of the various tobaccos, if, in fact, blended tobacco is employed, and the additives may be applied to one or all of the blend constituents. Under certain circumstances the additive may be incorporated into the tobacco before aging and curing, however, this would not ordinarily be done if the particular additive has a tendency to decompose during the aging and curing process. In the case of cigarettes the additive in some instances might be applied to the paper instead of to the tobacco.
The amount of additive in the final product contemplated by this invention is quite small but will vary videly with the particular additive employed and the amount of acid released upon burning or the flavor or aroma desired in the smoke. Thus an additive that releases only a comparatively small fraction of its total available flavoring acid on burning will be required in higher concentrations than those additives which are more eflicient with respect to the amount of flavoring acid released. Also it is well known that some of the aliphatic fatty acids having from 4 to 6 carbon atoms have a disagreeable odor per se when vapors of these acids are smelled in certain concentrations. However, in very low concentrations they provide in the tobacco smoke a desirable flavor and aroma, and the amount of additive in the tobacco should be such as not to exceed the amount which, when the tobacco is smoked, will release desirable quantities of the acid. This amount in many cases will be determined by actual experimentation. Generally speaking, however, desirable flavor and aroma are produced if the additives are incorporated into the final tobacco product in amounts between about 0.6] and 1.0 percent by weight (dry basis).
As pointed out in the copending Jones application hereinbeiore referred to, a number or" methods have been employed for incorporating acid-releasing compounds into cigarette tobacco and evaluating them for acid release. Certein of such methods are suggestive of procedures that may be used in actual commercial practice and include the following:
METHOD 1 One gram of shredded flue-cured tobacco was spread out on a watch glass of 10 cm. diameter. One milliliter of a solution of the additive in a suitable solvent such as ethyl ether was added uniformly to the tobacco from a pipette. The amounts of the additives vary but in general 10 milligrams of additive were applied to the one-gram sample. After the other had evaporated the tobacco was rolled into a cigarette which was stored at F. and about 60% relative humidity.
METHOD 2 A s nail quantity of liquid additive in the amount of l to 5 milligrams was streaked longitudinally along the paper of a cigarette by means of a stirring rod.
METHOD 3 The additive was dissolved in a volatile solvent, such as acetone, alcohol or ether, using 2 to 40 milligrams of additive per milliliter of solvent. One-fourth milliliter of the resulting solution was then distributed through a one inch portion (which was to be burned) of a cigarette by means of a A milliliter hypodermic syringe. The volatile solvent was then blown out of the cigarette with a stream of compressed air, leaving the additive dispersed in the cigarette.
METHOD 4 12 months at 75 F. and 60% relative humidity in order to ascertain the stability of the additive when stored on tobacco.
METHOD 5 The additive was dissolved in alcohol or other suitable solvent and sprayed onto one of the types of leaf tobacco that is used in a blended cigarette. This leaf tobacco was allowed to dry and was cut on a shredding machine. The shredded tobacco was blended with other types of shredded tobaccos that had not been treated with additive and the blend was made into cigarettes.
The compound or additive under test when applied to a low flavor tobacco or cigarette made therefrom as indicated in one of the foregoing methods was evaluated by organoleptic testing. This was carried out by smoking the cigarette and examining the smoke by sensory methods. In each of these tests special efforts were made to determine whether any acid odor was present in the smoke. This included a careful sensory study of both the main stream and the side stream. If the acid odor was detected in either the side stream or the main stream, it was concluded that the additive released the acid during the smoking or burning of the treated tobacco or cigarette.
In the foregoing, reference has been made to a general class of compounds which are useful as additives for tobacco in accordance with this invention. Certain of the specific compounds in this class are new and certain of them are not available commercially. Accg gdingly, several examples will be presented in the following disclosing methods of preparing representative compounds that are useful as additives in accordance with this invention. In each case the compounds which were prepared by the specific procedures given in the examples to follow were tested by one or more of the methods previously mentioned and each was found to release flavoring acid when smoked with tobacco. It will be understood that in the following, examples are given of preparing esters which will, upon burning or smoking of the tobacco treated therewith, liberate only one of the flavor-producing acids contemplated by this invention. However, it will be apparent .to one skilled in the art how other esters releasing other particular flavoring acids may be prepared. For example, in the following where there are given examples of processes of preparing esters of 3-methylvaleric acid it will be understood that essentially the same or similar means known to chemists could be employed for preparing the esters of other flavoring acids of the character hereinabove specified and that all such esters are contemplated as additives as within the scope of this invention.
Starch 3-methylvalerate A solution was prepared by heating a mixture of 8.1 grams of dried starch and 185 milliliters of formamide to 80 C. The mixture was cooled to room temperature and 13 grams of pyridine were added. To this resulting mixture were added 23 grams of 3-methylvaleryl chloride. After the mixture was allowed to stand 40 hours, it was poured into 2500 milliliters of cold 2 percent hydrochloric acid. The solid was collected by filtration and was washed repeatedly with 95 percent ethyl alcohol. The product weighed 7.3 grams.
Cellulose S-methylvalerate To a mixture of 62.5 grams of chloracetic anhydride, 20.8 grams of 3-methylvaleric acid and 0.05 gram of anhydrous magnesium perchlorate were added, with stirring, 5.2 grams of cotton. The resulting mixture was heated at 65 C. for 4 hours and was then allowed to stand for 16 hours. The mixture was poured into 750 milliliters of methylalcohol and the methanol solution was poured into 1 liter of water. The gummy oil was dissolved in acetone and was precipitated by addition of the acetone solution to methyl alcohol. The precipitate was washed with methyl alcohol and was dried in vacuo. The product weighed 3.6 grams and melted at 72-74 C. Additional material, 6.6 grams melting at 70-72 C., was obtained by pouring the methyl alcohol-acetone mother liquors into water.
Pectin 3-methylvalerate A mixture of 200 milliliters of formamide and 17.0 grams of dried pectin was heated and stirred for one hour until it formed a thick paste. To this were added 150 grams of pyridine and the mixture was cooled to room temperature. To the mixture were then added gradually 36.0 grams of 3-methylvaleryl chloride. The mixture was retained at room temperature for 20 hours after which it was poured into 2500 milliliters of cold 2 percent hydrochloric acid. The precipit-a-te was collected by filtration and was Washed repeatedly with cold 0.5 percent hydrochloric acid. The product weig-hed 7.7 grams.
Lignirz 3-methylvalerate To a cooled mixture of 8.4 grams of lignin (Indulin A) and 100 milliliters of pyridine were added slowly 9.5 milliliters (9.0 grams) of 3-methylvaleryl chloride. The mixture was allowed to stand at room temperature for 3 days after which it was heated under reflux for 4 hours. The reaction mixture was poured into 1 liter of ice water. The brown precipitate, which was collected by filtration, weighed 10.5 grams (78 percent). Purification was attempted by solution in acetone followed by precipitation in isopropyl ether. Such treatment allowed separation into a 1.3 gram portion, sintering and melting at 135- 155 C., and a 5.5 gram portion melting at 145-160 C.
It will be understood that the foregoing specific examples are only representative of the large number of esters of the polysaccharides, the conjugated saccharides and lignins that may be used to release flavoring acid on smoking of a tobacco treated therewith. It will also be understood that these compounds may be prepared by other methods that are well known to the art generally. The specific examples given are believed to be adequate to show the manner in which a large number of esters 6 r of the various hydroxy compounds and the several flavoring acids may be readily prepared.
A specific example of a method for incorporating the additive into a cigarette tobacco is as follows: Three hundred grams of tobacco strips were spread out on a table and the tobacco was sprayed with a solution of 3 grams of cellulose 3-methylvalerate in milliliters of alcohol. The treated strips were then mixed with 900 grams of burley strips and 1800 grams of flue-cured strips. The entire blend was shredded on a tobacco cutting machine and was manufactured into cigarettes. The cigarettes were'stored in a room maintained at 75 F. and 60% relative humidity. A test shortly after manufacture by a panel of smokers and a subsequent test at the end of days showed that the cigarettes released 3-methylvaleric acid into the smoke in pleasing amount.
Studies have been made in order to determine the extent to which various compounds will actually release acid when smoked with tobacco. As pointed out in the above mentioned copending Jones application, an arbitrary scale has been set up for comparing or evaluating the various additives that may be incorporated into tobacco. The additives which liberate the largest amount of acid on an organoleptic test basis during smoking have been arbitrarily assigned a rating of 10. The additives at the bottom of the scale liberating detectable but small quantities of acid on an organoleptic test basis have been assigned a rating of 1. Using this arbitrary scale and evaluating the various additives by a test panel of a number of smokers, the following ratings were arrived at for certain of the compounds contemplated within the scope of this invention and prepared as hereinabove indicated: the esters of starch have a 3 rating, the esters of lignin have a 6 rating, and the esters of cellulose and pectin have a 7 rating.
While the rating given a particular compound is indicative of acid release, it is not necessarily conclusive in evaluating that compound for commercial use as a tobacco additive. For example, some compounds having a high rating may have a tendency to be unstable under tobacco storage conditions, thereby prematurely releasing the acid, it being understood that it is generally desirable for the acid not to be released prior to smoking. Also it is pointed out that many of the polyhydric compounds from which the esters are prepared in accordance with this invention are naturally-occurring and certain of them are similar to those occurring in tobacco, hence the presence of such compounds or of their derivatives as a residue after the acid has been released does not introduce objectionable foreign types of constituents into the tobacco during the smoking procedure.
Also in accordance with this invention, it may in certain instances be desirable to employ an ester of the polyhydroxy compound wherein less than all of the hydroxyl groups in the compound are esterified with the flavoring acid. However, at least theoretically, such compounds are capable of releasing fewer molecules of flavoring acid per molecule of the ester. Generally, how ever, the degree of acid release in each instance should be tested by actual trial since the degree of acid release does not always appear to be directly proportional to the number of esterified groups in the hydroxy compound.
It will be understood that compositions have been prepared in accordance with this invention which have improved or enhanced aroma and flavor to give increased pleasure during smoking. Infinite variations with respect to the kinds and amounts of flavor-producing acids are possible and may be readily controlled. Such flavor-producing esters may be particularly useful with tobaccos which are ordinarily low in the type of flavor imparted by the flavoring acids. While the invention has been specifically described with reference to cigarettes, It will be apparent that it has application in the manufacture of other smoking tobaccos such as used for hand-rolled cigarettes, pipes and cigars.
' While several particular embodiments of this invention are shown above, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of this invention.
1. An article of manufacture comprising tobacco and an ester of a volatile organic acid having from 3 to 8 carbon atoms and a high molecular weight polyhydric compound selected from the group consisting of polysaccharides, conjugated saccharides and lignins.
2. A smoking tobacco having added thereto a small amount of an ester of a volatile organic acid having from 3 to 8 carbon atoms and a high molecular weight polyhydric compound selected from the group consisting of polysaccharides, conjugated saccharides and lignins.
3. The tobacco recited in claim 2 wherein said compound is starch.
4. The tobacco recited in claim 2 wherein said compound is cellulose.
5. The tobacco recited in claim 2 wherein said compound is pectin.
6. The tobacco recited in claim 2 wherein said compound is lignin.
7. A smoking tobacco having added therto a small amount of an ester of a volatile, monocarboxylic organic acid having from 3 to 8 carbon atoms and a high molecular weight polyhydric compound selected from the group consisting of polysaccharides, conjugated saccharides and lignins.
a 8. A smoking tobacco having added thereto between about 0.01 and about 1.0 percent by weight (dry basis) of an ester of a volatile, monocarboxylic organic acid having from 3 to 8 carbon atoms and a high molecular weight-polyhydric compound selected from the group consisting of polysaccharides, conjugated saccharides and lignins.
9. The tobacco recited in claim 8 wherein said acid has from 4 to 6 carbon atoms and said compound is starch.
10. The tobacco recited in claim 8 wherein said acid has from 4 to 6 carbon atoms and said compound is cellulose.
11. The tobacco recited in claim 8 wherein said acid has from 4 to 6 carbon atoms and said compound is pectin.
12. The tobacco recited in claim 8 wherein said acid has from 4 to 6 carbon atoms and said compound is lignin.
13. An article of manufacture comprising tobacco and a derivative of a high molecular Weight polyhydric compound selected from the group consisting of polysaccharides, conjugated saccharides and lignins, said derivative upon smoking with tobacco being capable of releasing a volatile organic acid having from 3 to 8 carbon atoms.
I References Cited in the file of this patent UNITED STATES PATENTS 231,682 Reiss Aug. 31, 1880 332,176 Yingling Dec. 8, 1885 770,883 Yingling Sept. 27, 1904 1,716,250 Thiele June 4, 1929