US 3095882 A
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United States Patent 3,095,832 TUBACCO FLAVORANTS John D. Hind and Frank H. Crayton, Richmond, Va, assignors to Philip Morris Incorporated, New York,
.Y. a co oration of Virginia NO him-3 Filed Aug. 4, 1961, Ser. No. 129,240 17 Claims. (Cl. 131-17) This invention relates to flavorants suitable for incorporation in tobacco and tobacco products. More particularly it relates to volatile flavorants which contribute to package aroma of tobacco products and/or to the flavor of the tobacco product upon its being smoked.
It has long been common to alter, enhance and improve the flavor and aroma of tobacco productsby 1ncorporating therein, by various methods, a variety of flavoring and other ingredients. Sugar, lrco-rrces, and other condiments have frequently been used for this purpose, and it has also been suggested to incorporate more uncommon flavorings on the leaf or even to in ect them within the living plant. The present invention, however, relates particularly to incorporation ofyolatrle derivatives of substances native to the tobacco itself to provide flavorful and useful enhancement of smoking products. The flavorants of this invention may be incorporated in the tobacco or placed on the filter or may be otherwise associated with the package.
A particularly sought after object in the tobacco preparation art is to enhance the sweetness of tobacco poducts. This has been attempted by addition to the tobacco of raw sugars, either as such or in the form of materials rich in sugars, e.g., molasses. Such materials, while altering the flavor of the tobacco product, are unsatisfactory in that their burning characteristics are markedly different from those of tobacco. Particularly where moderate or higher levels of sweetness are desired, either for their own flavor values or to complement other additives or flavors incorporated in the tobacco, it is found that loading the tobacco with substantial quantities of such sugars interferes with its combustion to an unacceptable extent.
We have found, in one aspect of our invention, that sweetening agents particularly well adapted for incorporation in tobacco products may be prepared from substances native to tobacco leaf. We have further found that such derivatives, Whether prepared from tobacco itself or synthetically, contribute the desired sweetness, yet do not interfere with combustion of the tobacco product.
We have also found that certain other derivatives of substances naturally occurring in tobacco, whether prepared from tobacco sources or synthetically, contribute subtle and highly pleasing characteristics other than sweetness to the smoke.
It is accordingly an advantage of this invention that sweetening agents and other flavorants are provided which do not interfere with the combustion of the tobacco product even when such agents are present in relatively high quantity. Thus, the flavorants of this invention are all volatile, by which is meant that they vaporize at a temperature below the pyrolysis temperature of tobacco and distill oif ahead of the coal, little if any of such materials being consumed by combustion. A further advantage of the present invention is that novel and useful subtle flavorants are provided for incorporation in tobacco in whatever combination or ratio may be desired.
In accordance with one mode of the present invention, desirable and useful flavorants for incorporation in tobacco products, which flavorants are characterized by volatility and by a sweet flavor, are prepared by alcoholysis of saccharides. Other desirable and useful products 3,095,882 Patented July 2., 1963 "ice which contribute desirable and characteristic odors to the tobacco product before and during smoking are de rived by alcoholysis of organic acids or mixtures thereof, and particularly by alcoholysis of organic acids which are native to tobacco, to provide products which volatilize below the pyrolysis temperature of tobacco.
The flavorful products may be incorporated in tobacco individually, with or without other commonly used flavors, humectants and other familiar additives, or they may be selectively combined and blended in appropriate proportion to provide dilfering subtle and pleasing characteristics to pack aroma and smoke.
The alcohols which may suitably be used in the prac tice of the present invention include the lower alkyl alcohols, i.e., those having from 1-6 carbon atoms. Other suitable alcohols may be determined by simple trial, the criterion being that the product be volatile below the pyrolysis temperature of tobacco and that the product have desirable characteristics of flavor and/or aroma.
A wide variety of saccharides may be used in the practice of this invention and include, without limitation, the monosaccharides, idisaccharides, trisaco'harides, tetrasaccharides and polysaccharides, so long as their reaction products with alcohol are volatile and pleasing, as above discussed. The monosaocharides, disaccharides and polysaccharides are generally preferred, and especially the hexoses, pent-oses, dihexoses, such as sucrose, and polyhexoses, such as dextrins, starches, and fructosans.
Likewise, the organic acids which may be rused to advantage are those which in reaction with the alcohol or mixture of alcohols employed 'will yield volatile prodnets of desirable characteristics. The preferred organic acids are those naturally occurring in tobacco, including the aliphatic polycarboxylic acids, particularly the alipliatic diand tri-carboxylic and hydroxycarboxylic acids, and include, without limitation, malonic acid, malic acid, succinic acid, tartaric acid and citric acid. Desirable flavorants include lower alkyl malates, lower alkyl mal onates, lower alkyl succinates, lower alkyl tartrates and lower alkyl citrates.
Desirable flavorants contributing a sweet flavor or aroma include, without limitation, (lower alkyl) oxymethyl furfurals and lower alkyl levnlinates.
The amount of flavorant incorporated in tobacco in accordance with this invention is largely a matter of choice. As a minimum, an effective amount should be incorporated to contribute a discrete aroma and/ or flavor to the product or to its smoke. Any larger amounts depend upon the character and extent of enhancement de sired, and we have found that their effect is more pleasing when subtle. We have found further, that the flavorants of this invention tend to complement each other and commonly used flavor additives and that by' varying proportions and amounts within the skill of the formulator, unusual pleasing and desirable effects can be achieved. The flavorants may be incorporated in tobacco by spraying, dipping, or other conventional means.
Appropriate process and equipment to prepare the flavorants of the invention will be apparent to those skilled in the art and form no part of the present invention. Suitable exemplary processes and equipment will be apparent from the following examples, which are intended to be illustrative and are not to be taken in a limiting sense. Except as otherwise indicated, all parts are by weight.
Example 1 3500 ml. of absolute methanol and 138.5 m1. of concentrated aqueous hydrochloric acid are placed in a 5- liter trident flask and heated to 40 C. 400 g. of sucrose fruity odor. The second fraction is substantially methoxymethyl furfural and has an odor suggestive of maraschino cherries. The over-all yield is 25 .3
Example 2 15 liters of anhydrous ethanol, 457 ml. of concentrated HCl and 2000 g. of sucrose are placed in a S-gallon carboy, which is shaken occasionally and then left to stand overnight. In the morning the carboy is placed in a constant temperature bath for three hours at 50 C. with continuous stirring to insure that all sugar is in solution. The bath is then brough to 75 C. and the carboy contents are held at that temperature for 24 hours. The mixture is thereafter cooled and neutralized with 391 ml. of 41% NaOH to pH 6.5. V
The reaction mass is vacuum distilled under continuous water aspirator vacuum to remove excess alcohol. The syrupy residue is ether-extracted in two batches in a continuous liquid-liquid extractor with ethyl ether, and the ether is removed by heating gently at atmospheric pressure. The two batches of extracted material are vacuum distilled at 1-2 mm. of mercury to produce four fractions for batch #1 and three fractions for batch #2. Fractions I and IV of batch #1 and Fractions 1 and iii of batch #2 are identified as ethyl levulinate (B.P. 51-64 C. at 2. mm. Hg) and etlioxymethyl furiural, respectively, by gas chromotography. The intermediate fractions are mixtures of the two. The yield of ethyl levulinate is 6.25 that of ethoxymethylfurfural is 9.0%; total yield is 23.5%
Example 3 12 ml. of concentrated aqueous hydrochloric acid and 500 ml. of n-propyl alcohol are placed in a one-liter trident flask equipped with an air-driven stirrer and a fractionating column. The flask contents are brought to 60 C. with a Glas-col mantle and 50 g. sucrose is sifted into the flask with continuous stirring. The sugar dissolves in about 14 hours. The reaction isa'ccompanied by color changes from clear and colorless to yellow, to orange, to red, and finally to black.
The solution is then distilled at an overhead temperature range of 87 C. to 97 C., yielding about200 ml. of distillate, principally the azeotrope of water and npropanol.
The contents remaining in the reaction flask are refluxed with continuous stirring for a total of 14 hours at 95 C. and then distilled until a head temperature of 95 C. is reached, at which point the distillate is dry (in the sense that it will not dissolve a crystal of sodium chloride). Approximately 250 m1. of product distillate are recovered.
The odor of the product, a black-walnut type note, indicates that esteriiicatio'n has taken place. The distillation range of the product corresponds to the boiling points of n-propyl levulinate and n-propoxymethyl furfural,
showing these expected compounds to have been formed.
500 ml. of 99% isopropanol is placed in a one-liter trident flask equipped with, an air-driven stirrer and a fractionating column. 12 ml. of concentrated aqueous hydrochloric acid is added and the temperature raised to 60 C. 50 g. of sucrose is shifted into the flask and the mixture is stirred constantly while the sugar is going into solution, a period of about l%.2 hours. The contents of the flask are then distilled to remove the water. The flask contents are refluxed at C.-82 C. for approximately 14 hours with constant stirring and then distilled at a head temperature of 82 C.
Approximately 220 ml. of product is removed from the reaction flask. The odor is similar to, but slightly dillerent from, that of the n-propyl levulinate and n-propoxymethyl turfural prepared in Example 3. The odor is reminiscent of nuts, but does not have the distinct blackwalnut type note which characterizes the n-propoxymethyl furtural.
Under vacuum distillation, a product yield of 19.95% is obtained. The material has a sweet, ethereal odor.
Example 5 V 50 g. of sucrose, 500 ml. of iso-butyl alcohol and 12 ml. of concentrated aqueous hydrochloric acid are reacted according to the procedure of Example 3. A 17.45% yield is obtained.
The products are identified by their distillation points as iso-butyl levulinate and iso-butoxymethyl furfural. Their odor is stronger and more distinct than that of the products prepared frornlower members of the alkyl alcohol series.
' Example 6 50 g. of sucrose and 500 ml. of n-butyl alcohol are placed in a one-liter trident flask equipped with an airdriven stirrer and a fractionating column. The tempera ture is raised gradually to 60 C. with a Glas-col mantle. The mixture is stirred for 3 hours and then allowed to stand over the Weekend. The temperature is again brought to 60 C. for 1 hour with stirring, additional water being added to bring undissolved sugar into solution. 12 ml. of concentrated hydrochloric acid is then added.
The procedures of Example 3 are followed to remove the product, the yield being 16.1%. The products are vacuum distilled and identified by their distillation points as n-butyl levulinate and n-butoxymethyl furfural. The n-butyl levulinate has a woody, ethereal odor that is rather sharp.- The n-butyoxymethyl furfural has a sweet but woody odor.
Example 7 10 g. of sucrose, m1. of n-hexanol and 0.5 ml. of concentrated hydrochloric acid are placed in a pressure bottle. The bottle is stoppered and partially immersed in a constant-temperature water bath. The reactants are maintained at 77 C. for 72 hoursand at 84 C. for 24 hours, whereupon the bath is allowed to cool with the bottle still immersed.
An aliquot of the reaction product, which is dark in color, is neutralized with sodium hydroxide to pH 7, evaporated to semi-dryness, and submitted to a panel for odor evaluation. The following subtle notes are detected: sweet and spicy; nutty (a green Walnut odor); fruity. All of these notes differ from those detectable in sucrose or in hexanol, and it is evident that they are present as a direct consequence of the reaction.
Example 8 To a pressure bottle are added 5 g. sucrose, 10 g. potassium acid sulfate (KHSO and 100 ml. of neutral ethyl alcohol. The bottle is loosely stoppered and immersed in a 70 water bath for 2 hours, being shaken occasionally during this time.
The reaction bottle is then placed in a 60 C. forced draft oven and heated for 16 hours. On removal from the oven, the contents are light yellow in color and have a very pleasant odor, quite difierent from alcohol, which indicates the predicted reaction has taken place. A test panel identifies these odor notesrin the sample: apple, fruit aroma and coconut.
Example 9 Three Erlenmeyer flasks are prepared, each containing 300 g. of dried bright tobacco stems (ca. 8% reducing sugar) covered with 700 ml. of anhydrous ethanol. The alcohol in flask #1 is acidified with 58 ml. of HCl, that in flask #2 with a mixture of 29 ml. HCl and ml. of concentrated H 80 and the third with 20 ml. concentrated H 80 All three flasks contain the same stoichiometric acid equivalents.
The flasks are placed in a water bath at 75 C. for hours and their contents are then neutralized. Samples are taken and diluted. Flavor and aroma are found to be most preferred in the H SO -catalyzed product, followed by the mixed acid product, and the HCl-catalyzed product is rated third.
Example 10 100 g. starch (dry Wt.) and 500 ml. of ethanol containing 7% HCl are added to a one-liter flask and refluxed 5 hours. Vacuum distillation of the reaction product gives 11 g. of ethyl levulinate and 3.9 g. of ethoxymethyl furfural.
Example 11 To a flask are added 5 g. of molasses, 200 rnl. anhydrous ethanol and 7.3 ml. concentrated H 80 The reactants are heated for 18 hours at 75 C. Flavor notes indicate that reaction of the character heretofore described has taken place.
Example 12 To a flask is added 5 g. fructose, 150 ml. SD #30 alcohol (ethanol containing about 10% methanol and 7.3 ml. of concentrated H 50 The flask contents are reacted for 96 hours, at elevated temperatures between 50 C. and 70 C. A sample is diluted with an equal volume of Water and neutralized with NaOH to pH 6.5. A sweet odor, very similar to the odor produced by the same reaction With bright stems, is found and can be detected even when the reaction mixture is diluted to 1:2000.
Example 13 To a one-liter flask are added 40 g. of DL malic acid, 1000 ml. of anhydrous ethanol and 70 ml. of acidic alcohol (16.2 g. HCl/ 100 ml. of ethanol). The flask is connected to upward air and downward water condensers and the contents are heated for 6 hours and 43 minutes, during which time 474 ml. of alcohol are removed. The flask contents are then neutralized to pH 7.0 with 41% NaOH. A 40.04 g. (73%) yield of the distillate of the expected boiling point is obtained when the residue is vacuum distilled at 2.5 of mercury. The product is identified as diethyl malate by gas chromatography.
Example 14 Esters of other acids may be prepared by the procedure of Example 13. Illustratively, by employing n-butanol and succinic acid there is obtained di-n-butyl succinate, which has an odor note of butyric acid, sweet, and with relatively low overall intensity.
Example 15 A five-gallon Pyrex carboy is loaded with 12.5 pounds of tobacco (dried bright stems) and covered with 12 liters of ethanol mixed with 1000 ml. of concentrated hydrochloric acid. The carboy and contents are maintained at a constant temperature of 68 C. for 17 /2 hours. The temperature is then raised to 75 C. for 4% hours. The liquor from the carboy is recovered and diluted to 12 liters with fresh ethanol and acid in the same proportions and poured into a second carboy containing 12.5 pounds of fresh dried bright stems. The procedure is as before, with recovery of liquor and its reaction with a third carboy of stems in the same manner.
The resultant product liquor obtained from the third carboy of the countercurrent series is neutralized to pH 6.3
with sodium hydroxide and placed under water aspirator vacuum to remove excess alcohol. The residue is transferred to a continuous extractor and run approximately 18 hours with ether. The ether is removed by boiling at atmospheric pressure and any remaining traces of ether are removed by placing the residue in a water aspirator vacuum. The product is placed in a Claisen flask and vacuum distilled at 2-3 mm. of mercury.
To an alcoholic solution of a portion of the light yellow distillate is added a reagent solution of 2,4-idinitrophenyl hydrazine and four derivatives are obtained. Two of these melt at the correct range for ethyl levulinate and ethoxymethyl furfural. Gas chromatographic separation of the products in the distillate shows it to consist principally of diethyl malate, diethyl succinate, ethyl levulinate, and ethoxymethyl furfural. These components are further identified by mass spectrometry and by infrared spectrophotometry.
The separated components may be blended with tobacco singly or in desired admixture.
Example 16 The pleasing, distinctive and subtle attributes of exemplary flavorants in accordance with this invention when embodied in smoking products are illustrated by the present example. Three lots of regular cigarette filler, weighing ten grams each, are sprayed With a mixture of ethoxymethyl furfural, ethyl levulinate, diethyl malate, diethyl succinate, and diethyl citrate. Half the mixture comprises ethoxymethyl furfural and ethyl levulinate, prepared as in Example 2, and the other half comprises substantially equal parts of the three specified compounds, all parts being by Weight. The amount of the mixture of flavorants applied to the filler is about 0.3% by weight of the filler. Amounts within the range of 0.1% to 1% have been found satisfactory, with 0.2% to 04% being preferred.
The treated filler is dried and made into cigarettes for evaluation of pleasing odor and taste. The cigarettes so prepared and untreated control cigarettes are submitted to a panel of three judges, who use a 0-10 intensity scale in aid of evaluation.
The panel finds that the cigarettes containing the flavorful additives of this invention are characterized by a fruity odor in unlit draw taste and in smoke taste and are readily distinguishable from the controls. The flavorants are found to enhance significantly the taste and odor of the tobacco filler. Data from the test is given below.
1. A tobacco product containing a flavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being the reaction product of an alcohol and a member of the group consisting of saccharides and organic acids native to tobacco.
2. A product containing a flavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being the reaction product of a lower alkyl alcohol and a saccharide.
3. A tobacco product containing a flavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being the reaction product of a lower alkyl alcohol and a member of the group consisting of hexoses, pentoses, dihexoses, dextrins, starches and fructosans.
4. A tobacco product containing a fiavorant characterized in being volatile below the pyrolysis temperature of tobacco, said fiavorant being a (lower alkyl) oxyrnethyl furfural.
5. A tobacco product containing a flav-orant characterized in being volatile below the pyrolysis temperature of tobacco, said fiavorant being a lower alkyl levulinate.
6. A tobacco product containing ethoxyrnethyl furfural.
7. A tobacco product containing ethyl levulinate.
8. A tobacco product containing a ilavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being the reaction product of a lower alkyl alcohol and an organic acid selected from the group consisting of aliphatic diand tri-c-arboxylic and hydroxycarboxylic acids.
9. A tobacco product containing a fiavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being a lower alkyl malate.
10. A tobacco product containing a fiavorant characterized in being volatile below the pyrolysis temperature of tobacco, said fiavorant being a lower alkyl succinate.
11. A tobacco product containing a flavorant characterized in being volatile below the pyrolysis temperature of tobacco, said fiavorant being a lower alkyl citrate.
12. A tobacco product containing a flavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being a lower alkyl malonate.
13. 'A tobacco product containing a flavorant characterized in being volatile below the pyrolysis temperature of tobacco, said flavorant being a lower alkyl tartratc.
14. A method of enhancing the flavor and aroma of a tobacco product which comprises incorporating in said tobacco product an efiective amount of at least one flavorant which is the reaction product of an alcohol with a member of the group consisting of saccharides and aliphatic diand tri-carboxylic and hydroxycarboxylic acids, said fiavorant being characterized in being volatile below the pyrolysis temperature oftob'acco.
15. A method of enhancing the flavor and aroma of a tobacco product which comprises incorporating in said tobacco product an effective amount of a flavorant which is the reaction product of a lower alkyl alcohol and a member of the group consisting ot aliphatic diand tricarboxylic and hydroxycarboxylic acids, said fiavorant being characterized in being volatile below the pyrolysis temperature of tobacco.
l6. Amethod of providing a sweet flavor in the smoke of a tobacco product which comprises incorporating in said tobacco product an'effective amount of the reaction product of an alcohol and a saccharide, said reaction product being characterized in being volatile below the pyrolysis temperature of tobacco.
17. A method of providing a sweet flavor in the smoke of a tobacco product which comprises incorporating in said tobacco product an effective amount of the reaction product of at least one lower alkyl alcohol and at least one member of the group consisting of hexoses, pentoses, dihexoses, dextrins, starches and fructosans, said reaction product being characterized in being volatile below the pyrolysis temperature of tobacco.
References Cited in the file of this patent UNITED STATES PATENTS 2,766,145 Jones Oct. 9, 1956 2,766,146 Ashburn Oct. 9, 1956 2,766,150 Teague Oct. 9, 1956