US2644462A - Tobacco treatment - Google Patents

Description

Patented July 7, i953 'ToBAcoo TREATMENT Walter G. Frankenburg, Millersville, Pa., assignor to General Cigar (10., Inc., New York, N. Y., a corporation of New York g No Drawing. Application November-1,1947, Y I Serial No. 783,626

, 10 Claims.

, This invention relates to the treatment of tobacco and, more particularly, to the fermentation of tobacco toirender the tobacco tender and pleasant-smelling and to developisuch smoking qualities as aroma and mellowness.

In general, tobacco which has been harvested is cured (dried) by hanging the leaves in a suitably ventilated barn. During the curing period which is usually about 4 months, the tobacco mentation.

commercial application.

bacco.

procedures.

which follows.

numbers 25 to '28, (Mn, Fe, Co and Ni), in-

elusive. It is advisable to select compounds ofstable under the conditions of fermentation. Manganese and iron catalysts are preferred. Catalysts comprising two metals either as physical mixtures of two metal compounds or as single complex compounds containing the desired metals are often used to advantage. Such salts of the-catalytic metals as the nitrates, sillfates, acetates, citrates and tartrates represent suitable catalysts for the process of my inven- The catalyst is usually applied to the tobacco before fermentation in the form of an aqueous solution either by spraying the solution or by dipping the tobacco in the solution. The addition of water to cured and sweated tobaccopreparatory to fermentation or resweating is a conventional operation. In essence, therefore, my invention involves the selection of chem-=, ical substances which promote or catalyze the fermentation of tobacco and the addition of these selected substances to tobacco undergoing fer- The proportion of catalyst added to the tobacco will varywith the nature of the particular tobacco that is being treated and the selected catalyst and the results which are to be achieved In general, the proportion of catalyst is less than 0.5% by weight of the dry tobacco, and preferably is in the range of about 0.005% to 0.1%, the foregoing percentages being based on the molecular weight of the catalytic element or metal in the catalyst compound. As a rule, tough tobaccos, i. e., those failing to respond satisfactorily to fermentation without added catalysts, and tobaccos having unusually high contents of nicotine show more markedly the benefits of my catalytic fermentation process, which include, in some instances,

In the preparation of cigarette tobacco, "a slower and less vigorous form of fermentation known as aging is practiced. My fermentation For in stance, an aqueous solution of the catalyst is sprayed on the tobacco, say in an amount not exceeding 5%--byweight of the dry tobacco. Thusya concentration of catalytic metal, e. g., manganese and/or iron, corresponding to about from 0.01% to 0.05% by weight of the dry tobacco is introduced and the tobacco is then subjected to the usual aging process.

undergoes certain chemical changes and turns brown. Thereafter, the tobacco leaves are graded according to size and quality and the various grades are packed incases to undergo natural tion. sweating. Tobacco isfrequently sweated for a period of 2 to 3 years during which time additional chemical changes occur in the tobacco leaves. The next step in the preparation of tobacco for smoking purposesis fermentation or resweating; fermented tobacco is frequently re 'ferred to as resweated tobacco because the pre- V liminary or first sweating is a mild form of fer- In spite of the extensive art bearing on the fermentation of tobacco, occasions arise when tobacco of a given harvest year or locality or mentation. species fails to respond satisfactorily to the known methods of, fermentation and, accordingly, cannot be utilized in the production of cigars, cigarettes and 'othersmoking products. It is clear that these vagaries of certain lots of by the fermentation. tobacco lead to considerable economic losses for which, to my knowledge, no remedy has been previously suggested, much less developed for The principal object of this invention is to pro- 35, vide an improved process for fermenting to= Another important object is to provide a'process for fermenting tobacco which does not satisfactorily respond to conventional fermenting 40 A further object is to develop superior smo'ka c lerati n of fermentation. ing qualities in tobacco, particularly tobacco of low grade, by fermenting the tobacco in the presence of promoters or catalysts. p

Additional objects andadvantages of my catalysts are' advantageously used in the convention will be evident from the description v t m aging cigarette t I have discovered that thereare chemical substanceswhich when added to tobacco which is ,50 to be fermented act as promoters or catalysts in the fermentation process.- The catalysts of my invention are compounds of elements of Series 4 of the Mendeleeff Periodic Table having atomic sweat.

Further refinements of the process which I have developed include pressure changes and wetting agents. By subjecting tobacco to a reduced pressure, say below 50 mm. Hg absolute, and immersing the thus vacuumized tobacco in an aqueous catalyst solution, the liquid infiltrates more thoroughly and quickly into the tobacco because the plant cells are at least partially evacuated of gas which tends to obstruct the penetration of liquid. Wetting agents add" ed to the aqueous catalyst solution also function to drive the liquid into the tobacco and thus aid in the fermentation process. Less than 0.05% by weight of wetting agents like sulfonated alcohols or sulfonated alkyl benzenes dissolved in the aqueous catalyst solution materially improves the penetration of the liquid into the tobacco.

For a more detailed description and further clarification of my invention, specific examples will now be presented.

Eaz'cmpie 1 Pennsylvania broadleaf tobacco grown in abnormally dryseason washarvested, cured and subjected to a three-year period of natural After this initial processing, the tobacco was still very hard to ferment. The tobacco consisting of leaves 22 inches in length was of an orange color and felt gummy and soft; all these signs indicated. its rawness. The nicotine content was 5.2% by weight of the dry tobacco. Such a highnicotine content is characteristicoi tobacco which is very resistant to fermentation.

.A 300-110. case of thistobacco was divided into twoequal test lots A and B. ,Lot. A was immersed in water so that it took up an amount of water equal to 48% of the-dry tobaccoweight. Lot B was similarly immersed in an aqueous solution of fermentation catalyst. The composition of the solution was:

Water gallons 90 Manganese sodium. citrate (Mn content about (manganese citrate soluble N 'F. VII) "pounds" 2.2 Wetting agent (dioctyl ester of sodium sulfo succinic acid); ounces 4.5

relative humidity and 112 F. After a days, the

cases were removed. from thisroom, opened, and the tobacco of each case shaken and repacked. The cases were brought back into the heated 100111 and remained. there 7 days (second heat). Another shaking then followed. The two cases were returned to the fermenting room for a third heat of 12 days, a fourth heat of 21 days, a fifth heat of 4 /2 weeks, a sixth'heat of 1 /2 months, and a seventh of 2 /2 months, each heat-following a shaking and repacking operation.

After the fourth heat, the tobacco of lot B which had received the solution containing manganese, showed 'a more pronounced loss of surface gums, a slightly darker color, a more tender textureand a cleaner, less-pungent smell than the tobacco of lot .A which received only water. This difierence in favonof iotB containingxthefermentation catalyst became more and moremarked with the continuation of the fermentation process. .Afterthe seventh heat,

strong in texture and unclean in smell.

nicotine content of 1.63%

the tobacco of lot 13 had lost all its moisture, was dark brown, very tender in texture and possessed a slightly ammoniacal aromatic odor, whereas the tobacco of lot A was still slightly moist, Even after an additional heat, the tobacco of lot A was still inferior in feel, appearance and smell to that of .lot B. By chemical analysis, the fermented (seven heats) tobacco of the catalyst lot B had a by weight of dry tobacco, while the fermented (eight heats) tobacco of the water lot A had a nicotine content of 2.32%. Smoking tests showed conclusively that .theitobacc'o .of lot B was superior to that of lot A..in burning characteristics, mildness and Example 2 Pennsylvania tobacco which was grown in a very dry season, cured'and stored for a period of natural swea; of four years, showed all the exterior signs of abnormal 'rawness or toughness. This tobacco, consisting of 18-inch leaves, was known to yield an end product of unsatisfactory smoking qualities, even if fermented under drastic conditions. 'Two lots C and'D of this tobacco were used in comparative tests.

The'tobacco of lot C was immersed in an aqueous solution containing by weight 0.3% of manganese sodium citrate, 0.5% of iron ammonium citrate (iron content 17.5%) and 0.035% of wetting agent '(dioctyl ester of sodiumsulfosuccinic acid). Ihe tobacco'took up an amount of catalyst solution corresponding to 51% of its Weight before immersion. Fermentation was conducted in a series of heats and shakings as described in Example 1 except that the heat' periods were about 25% shorter. During the third heat, the tobacco showed a spontaneous rise of its temperature, reaching a maximum temperature of 129 F. After the third heat, the color of the tobacco changed to a very dark brown. Starting with the fifth heat, the tobacco texture began to become considerably more tender, and the smell started to change to the typical ammoniacal, aromatic odor characteristic of well fermented tobacco. After the sixth heat, the fermentation was stopped and the tobacco possessed very acceptable smoking quali= ties. Thenicotine content had decreased from 6.1% to.2.3%.

The tobacco of lot 1) was immersed in water containing only 0.0l% by weight of the wetting agent used in connection with lot C. The tobacco took up an amount of water corresponding to 52% by weight of dry tobacco. The tobacco did notrespond at alltoefiortsto start itsfermentation, although it was subjected to eight heats and shakings. The nicotine content only decreased from 5.5% to 4.9%, and the smoking qualities of 7 the tobacco were distinctly unacceptable.

Example '3 I tation; the quantity of manganese compound thus introduced into the tobacco was about 0.06% by weight of the dry tobacco. The catalytically fermented tobacco was successfully employed as binder tobacco in making c s.

As indicated hereinbefore, good fermentation of tobaccois evaluated in terms of the properties of the fermented tobacco. Thus, it is generally observed that satisfactory fermentation weakens the tobacco tissues so that the tobacco becomes desirably tender, eliminates or materially decreases surface gums so that the gummy feel of tobacco is destroyed, develops a pleasant aromatic odor in the tobacco, reduces the alkaloid (especially nicotine) content of the tobacco, and renders the tobacco milder in smoking tests. The value of the catalytic fermentation process of my invention is more readily appreciated when judged on the basis of the foregoing criteria.

While I have referred to compounds of manganese, iron, cobalt and nickel as promoters or catalysts for the fermentation of tobacco, the exact role of these compounds which I add to tobacco is not clear to me. However, it is sufficient that desirable results are obtained when tobacco is fermented in accordance with the teachings of this specification.

The term, fermentation, has herein been used in the same general sense commonly understood in the tobacco industry; that is to say, the term does not imply that any process simila to the process of alcoholic fermentation occurs in tobacco and does not mean that microorganisms are necessarily involved. Furthermore, it is well known in the tobacco industry that the fermentation of tobacco commences at about room temperature. Thus, studies on the fermentation of tobacco were reported in 1934 in the Journal of Agricultural Research (volume 49, No. 2, page 145) showing that fairly evident thermogenesis (generation of heat), which is characteristic of tobacco fermentation, begins at about 16 C. (61 F.).

The foregoing description and examples are intended to be illustrative only. The many possible variations and modifications of my invention conforming to its spirit are to be considered within the scope of the appended claims.

What I claim is:

1. In the fermentation of tobacco, the improvement which comprises wetting tobacco substantially uniformly with an aqueous solution of a water-soluble, fermentation catalyst compound of an element selected from Series 4 of the Mendeleeff Periodic Table and having an atomic number between 25 and 28, inclusive, and subjecting the tobacco with the thus applied catalyst compound to fermentation in the temperature range of about 16 to 54 C.

2. The process of claim 1 wherein the selected element is manganese.

3. The process of claim 1 wherein the quantity of fermentation catalyst compound applied to the tobacco is in the range of about 0.005% to 0.1% by weight of the dry tobacco, said percentage being based on the molecular weight of the catalytic element in said fermentation catalyst compound.

4. The process of claim 1 wherein the tobacco is subjected to a pressure substantially below atmospheric pressure to vacuumize the same, and the aqueous solution of the fermentation catalyst compound is then applied by immersing the vacuumized tobacco in said aqueous solution.

5. The process of claim 1 wherein the aqueous solution of the fermentation catalyst compound contains a wetting agent to facilitate penetration of said aqueous solution into the tobacco.

6. The process of claim 5 wherein the watersoluble, fermentation catalyst compound is manganese sodium citrate.

7. The process of claim 1 wherein the tobacco initially has a nicotine content exceeding about 5% by weight of the dry tobacco.

8. The process of claim 7 wherein the selected element is manganese.

9. The process of claim 7 wherein the aqueous solution of the fermentation catalyst compound contains a wetting agent to facilitate penetration of said aqueous solution into the tobacco.

10. The process of claim 9 wherein the watersoluble, fermentation catalyst compound is manganese sodium citrate.

WALTER G. FRANKENBURG.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Technical Mycology, La Far, Dgs. 45 to 48, inclusive, 1903,

Annual Review of Biochemistry, vol. V, 1936, pg. 28.

Journal of Biological Chemistry, vol. 155, Sep- I tember-October 1944, pp. 137 to 141, inclusive.

Claims (1)

1. IN THE FERMENTATION OF TOBACCO, THE IMPROVEMENT WHICH COMPRISES WETTING TOBACCO SUBSTANTIALLY UNIFORMLY WITH AN AQUEOUS SOLUTION OF A WATER-SOLUBLE, FERMENTATION CATALYST COMPOUND OF AN ELEMENT SELECTED FROM SERIES 4 OF THE MENDELEEFF PERIODIC TABLE AND HAVING AN ATOMIC NUMBER BETWEEN 25 AND 28, INCLUSIVE, AND SUBJECTING THE TOBACCO WITH THE THUS APPLIED CATALYST COMPOUND TO FERMENTATION IN THE TEMPERATURE RANGE OF ABOUT 16* TO 54* C.