US 3851653 A
A method is provided for treating tobacco to increase the volume of the tobacco and reduce the nicotine and tar content of the tobacco. According to the method of the invention, tobacco is treated with a given amount of catalase and an aqueous solution containing a given amount of hydrogen peroxide, with the hydrogen peroxide and catalase being applied either simultaneously or first with the hydrogen peroxide and then with the catalase. The treated tobacco thus produced is especially useful in the manufacture of cigarettes and the like.
Description (OCR text may contain errors)
United @ttes ent 1 Rosen  Inventor: William E. Rosen, Lafayette Hill,
 Assignee: Rosen Enterprises, Inc., Lafayette Hill, Pa.
[ Notice: The portion of the term of this patent subsequent to Oct. 12, 1988, has been disclaimed.
 Filed: Oct. 11, 1972  App]. No.: 296,739
 US. Cl. ..131/140 P, 131/141, 131/142,
 Int. Cl. A24b 15/02, A24b 03/18  Field of Search 204/157.1 S; 131/15, 17,
 References Cited UNITED STATES PATENTS 3,612,065 10/1971 Rosen 131/142 A OTHER PUBLICATIONS Sonochemistry: The Production of Chemical Changes with Sound Waves from the Journal of the Acoustical Society of America, Vol. 25, No. 4, July 1953, pages 651-657.
Primary ExaminerMelvin D. Rein Attorney, Agent, or FirmStephen E. Feldman ABSTRACT 19 Claims, N0 Drawings *Dec. 3, 1974 METHOD OF PUM ING TOBACCO AND REDUCING NICOTTNE CONTENT THEREOF BACKGROUND OF THE INVENTION The present invention relates to a method of treating tobacco. More particularly, the invention is directed to a method of puffing tobacco to increase its volume and reduce the nicotine content thereof.
Tobacco which has been treated so as to substantially increase its volume is generally referred to as puffed tobacco. Various methods have been suggested in the prior art to manufacture puffed tobacco. These methods have, however for the most part, proven to be completely unsatisfactory. Certain of the suggested methods cause a substantial portion of the cell walls of the tobacco to rupture which significantly decreases the physical strength of the tobacco. Other methods also have a rather severe adverse affect on the taste of the tobacco. The methods heretofore suggested were also economically unfeasible for commerical production.
In addition to the disadvantages of large capital outlays for treating solvents and machinery, poor taste, and cell wall rupture, which have been characteristic of prior art methods, these previous methods have also suffered from the disadvantages of lack of elasticity in the tobacco, much breakage of the tobacco resulting in undesirable fines, and the presence of residues some of which are toxic. Furthermore, it is known that tobacco readily absorbs the aroma of many materials which come into contact with it. Hence, undesirable effects are often produced with solvent materials used in puffing processes of the prior art. Attempts have also been made to reduce the nicotine and tar content of tobacco in an economical manner without adversely affecting the desirable properties of the tobacco, especially taste, but such attempts have been without much success.
A successful method of puffing or expanding tobacco has been described in my previous U.S. Pat. No. 3,612,065 issued Oct. 12, 1971 for Method of Puffing Tobacco and Reducing Nicotine Content Thereof. The process of that patent involves the treatment of tobacco with catalase and thereafter by treatment with an aqueous solution of hydrogen peroxide, whereby the catalase reacts with the hydrogen peroxide to release oxygen which increases the volume of the tobacco. Such a process is extremely successful in alleviating many of the above listed disadvantages of prior art processes. However, even more successful processes are being sought.
BRIEF SUMMARY OF THE INVENTION The above and other disadvantages of the prior art are alleviated by the process of the present invention which comprises the steps of contacting tobacco with an aqueous solution containing a given amount of hydrogen peroxide and simultaneously or subsequently providing on said tobacco a given amount of catalase, the given amount of catalase being effective to cause decomposition of the given amount of hydrogen peroxide and the given amount of hydrogen peroxide being effective upon decomposition to increase the volume of the tobacco treated. Where the catalase is applied to the tobacco simultaneously with the hydrogen peroxide, it is preferred that a delayed catalase be used.
The process of the present invention produces a degree of puffing virtually equal to the process of my previous US. Pat. No. 3,612,065. In addition, where the hydrogen peroxide is added prior to the addition of the catalase or where a delayed catalase is used, according to the process of the present invention, the added advantages of sterilization of the tobacco and elimination of tobacco beetle larvae are also achieved. The simultaneous addition of hydrogen peroxide and catalase can result in reduced equipment and processing costs as well as reducing the total amount of moisture added to the tobacco. The latter is a very important consideration in tobacco processing since the less moisture added, the less tobacco solubles will be removed and the better will be the tobacco taste and elasticity of the tobacco.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various species of tobaccos may be treated in accordance with the present invention. The tobaccos, when treated, are preferably in the cured state as opposed to the green state. The tobacco may be in various physical forms. Advantageously, tobacco is treated in the leaf form. However, tobacco may also be satisfactorily treated in the shredded form, customarily used for the manufacture of cigarettes or in any other form.
The effective compound which is employed to cause the decomposition of the aqueous hydrogen peroxide solution is catalase. Catalase is a red crystalline enzyme which is a protein complex with hematin.
Catalase may be applied to the tobacco in the puritied form in order to decompose the hydrogen peroxide. Catalase is, however, a natural enzyme which is produced by certain plants and in particular yeast. Since yeast is inexpensive to purchase and, if desired, can be cultivated with little or no difficulty, yeast is accordingly the preferred source for the catalase.
The yeast which may be employed in this invention must be an active live yeast if the yeast plants are to be cultivated to produce the catalase. The particular strain of yeast which is employed is not critical. Excellent results have been obtained with the common baker type yeast, as well as with the brewers-type yeast. Other types of yeast are also suitable for employment in this invention. The principal criterion of the yeasts which are used in this invention is that the yeast contain or produce sufficient amounts of catalase to cause the decomposition of the hydrogen peroxide solutions so as to produce large volumes of gases. The yeast that is selected should not impart adverse properties to the treated tobacco, especially with regard to taste.
The aqueous hydrogen peroxide solutions which are employed in the process of this invention are commercially available. The hydrogen peroxide solutions which are used, for example, may be the commonly available 3 percent hydrogen peroxide solutions. Superoxol (30 percent hydrogen peroxide) can also be used as a stock material and diluted as required with water to obtain the desired strength hydrogen peroxide solution. There is no exact lower limit with regard to the strength of the hydrogen peroxide solutions which may be employed in the present invention. However, for practical purposes the strength of the aqueous hydrogen peroxide solution should be between 10 and 50 volumes with the most preferred results being obtained when a 20 to 40 volume peroxide solution is employed.
The most convenient method of applying the catalase to the tobacco is in the form of an aqueous dispersion of a suitable yeast. The tobacco can advantageously be treated by immersing the tobacco into the aqueous yeast solution. However, in the case of certain forms of tobacco, for example, shredded tobacco, it is considerably simpler to spray the aqueous dispersion of the yeast onto the tobacco. The yeast can also be applied to the tobacco in the dried state. In this method, the yeast is sprinkled or spread in a relatively uniform manner over the tobacco to be treated.
The hydrogen peroxide can be applied to the tobacco in substantially the same manner as that employed for the aqueous dispersion of the catalase or yeast, that is, the hydrogen peroxide may be applied by immersing the tobacco into a hydrogen peroxide solution or by spraying the hydrogen peroxide solution onto the tobacco.
As indicated previously, the catalase is applied to the tobacco either simultaneously with or subsequent to contacting the tobacco with the aqueous solution of hydrogen peroxide. That is, the hydrogen peroxide is applied to the tobacco no later than the application of the catalase. For example, the tobacco may be first immersed in a solution of hydrogen peroxide and then immersed in a solution of catalase. Alternatively, the to bacco may be simultaneously sprayed with solutions of hydrogen peroxide and catalase. In a particularly preferred embodiment, the tobacco is treated simultaneously with a solution of hydrogen peroxide and delayed catalase, either by immersing or by spraying.
Where a delayed catalase is used, the catalase may be inhibited or immobilized in any of a number of known manners. For example, the catalase may be inhibited by treating with citric acid or ethyl alcohol or other known inhibitors. Alternatively, the catalase may be immobilised by rendering it insoluble or by encapsulating it. Such methods are described, for example, in Immobilized Catalase by J. Balcom et al. in Process Biochemisrry, Aug, l97l, pages 42 et seq.
The activity of the catalase may be delayed for any suitable period of time from a few seconds up to 5 or minutes or more. A period of 5 minutes is usually adequate to allow the hydrogen peroxide and catalase to penetrate the tobacco cells and allow the hydrogen peroxide to sterilize the tobacco and kill beetle larvae. The delay of the catalase allows the hydrogen peroxide and catalase to be mixed together separate from the tobacco and then sprayed on the tobacco or serving as a mixture into which the tobacco may be dipped.
Almost as soon as the catalase and the hydrogen peroxide solutions are brought into contact, there is a considerable evolution of gases. If yeast is used as the source of catalase, CO gas is produced along with the oxygen formed when the hydrogen peroxide decomposes into water and oxygen, The rapid, almost violent decomposition of the hydrogen peroxide, is caused by the enzyme catalase. It is the evolution of the gases from the reaction of the catalase and the hydrogen peroxide which causes the tobacco to expand to a larger volume and consequently a lower density to provide the puffed tobacco product of this invention.
The amount that the volume of the tobacco is increased by the process of this invention is directly related to the strength of the hydrogen peroxide solution employed. The higher the strength of the peroxide used, the greater will be the increase in the volume of the tobacco. However, there is a maximum limit to the strength of the hydrogen peroxide which can be employed, since excessively strong solutions will cause excess oxidation of the tobacco itself which is highly undesirable. For example, it should be noted that superoxol which is one hundred volume peroxide, could cause excessive oxidation of the tobacco if applied in the undiluted form. The optimum concentrations of hydrogen peroxide for employment in this invention are those which contain from 10-50 and more preferably 20-40 volumes of hydrogen peroxide.
The amount of catalase which is applied or produced on the tobacco is directly related to the amount of hydrogen peroxide which is employed. The amount of yeast should be sufficient to produce an amount of catalase which is sufficient to decompose all of the hydrogen peroxide which is employed.
The relative amount of the yeast which must be employed in order to insure that sufficient catalase will be present to completely decompose the hydrogen peroxide will vary considerably depending upon the particular strain which is employed and the reaction conditions under which the process of the present invention is conducted. The exact amount of a given strain which is required in order to decompose a given amount of hydrogen peroxide can readily be determined by wellknown standard laboratory tests for detecting and measuring hydrogen peroxide content. The most commonly used reagent for the detection of hydrogen peroxide is titanium sulfate. A solution of this compound gives a yellow to red color with an acidified solution of hydrogen peroxide. Accordingly, by varying the relative amounts of the yeast and thereby the catalase content and the hydrogen peroxide,.the desired increase in volume can be obtained with the complete decomposition of the hydrogen peroxide.
In addition to increasing the volume of the tobacco, the tobacco is bleached and certain undesirable components in the tobacco are reduced. In particular, it should be noted that the nicotine in the tobacco is oxidized by the oxygen which is liberated on decomposition in the hydrogen peroxide reaction into the relatively harmless products including nicotine acid and certain other relatively harmless organic products. The reduction in nicotine is especially noticeable if a catalytic amount of nitric acid is added. It has also been found that to some degree, the relative amount of tar in the tobacco is also reduced by the process of the present invention. The exact mechanism by which the tar is reduced is not known but it is believed to be a combination of both the action of the enzymes on the tar and oxidation of the tar by the oxygen produced by the decomposition of the hydrogen peroxide.
Furthermore, it is believed that the evolution of gases from the reaction of the catalase and hydrogen peroxide is responsible for lightening the color of the tobacco, increasing the sugar content of the tobacco and ultimately decreasing the contents of benzopyrene, phenols and other undesirable components of the tobacco. As a result, whereas it is normal procedure to cure tobacco under conditions of strict temperature and humidity for long periods of time ranging up to 2 years or more, the process of the present invention provides a much quicker method of curing the tobacco, which can also be carried out on the whole tobacco leaf including the stem.
The method of the present invention is advantageously conducted at room temperatures to slightly elevated temperatures (e.g., -l40 F). The catalase and the hydrogen peroxide will readily react in this temperature range to produce the desired evolution of gases. The higher the temperature the stronger will be the decomposition reaction and the faster the cure and the greater the puff. Thus, a degree rise in temperature will approximately double the force of the hydrogen peroxide reaction. The temperature should however be kept below 140 F. since the catalase will ultimately be destroyed at higher temperatures. This upper temperature limit will of course vary somewhat depending upon the particular strain of yeast which is employed. In any event, quite satisfactory results may be obtained by conducting the method at ambient temperatures of about 30 C.
The degree of treatment to the tobacco, using the method of the present invention, can be readily controlled by several expedients. As noted above, the increase in the volume of the tobacco can be controlled by increasing or decreasing the concentration of the hydrogen peroxide. A further method which has proven to be quite satisfactory is to kill the yeast with heat when the tobacco reaches the desired increase in volume, in that the catalase production is likewise stopped. This also prevents any latent yeast on the tobacco from growing and producing enzymes which might possibly further affect the tobacco during storage. The puffed product of the present invention is dried to the desired degree of moisture content in the conventional manner.
The cost of treating tobacco in accordance with the invention is relatively low. With the exception of the cost of hydrogen peroxide which is readily commercially available at a reasonable price, there are no other substantial material costs involved in that the yeast which produces the catalase can be readily cultivated in sufficient quantities at minimal costs.
It will of course be understood that the process of the present invention is not limited to a single treatment of the tobacco with hydrogen peroxide and catalase. On the contrary, repeated treatments of the tobacco with hydrogen peroxide and catalase may be carried out and are contemplated within the scope of the present invention. Such repeated treatments may be advantageous where extremely high degrees of puffing are desired but strong concentrations of hydrogen peroxide necessary to attain such degree of putting in a single treatment are to be avoided. I
The method of forming the hydrogen peroxide solution is not critical to the present invention, and according to one embodiment of the present invention the hydrogen peroxide may be formed in situ with the tobacco. That is, the tobacco may be immersed in distilled water in which oxygen has been dissolved, and ultrasonic energy may be applied to the water to cause the water and oxygen to form hydrogen peroxide. Alternatively, a weak solution of hydrogen peroxide may be concentrated by dissolving extra oxygen in the solution and then applying ultrasonic energy. For example, one half pound of a 6 percent hydrogen peroxide solution containing dissolved oxygen may be increased to 27 percent hydrogen peroxide by exposure to a watt beam at frequencies of 400 kilocycles for about 10 minutes. Similar concentrations can be achieved starting with oxygen dissolved in distilled water, as will be evident to one of ordinary skill in the art.
The processes of the present invention will now be described in more detail with reference to the following specific, non-limiting examples:
EXAMPLE I A mixture of 100 volume hydrogen peroxide was diluted to concentrations of 0.5 percent, and an aqueous catalase extract was also diluted to 0.5 percent. The hydrogen peroxide solution was applied first onto cut lamina of tobacco by spraying, followed by the catalase solution which was also applied by spraying. After several minutes the tobacco has puffed, and the puffed tobacco was then dried by conventional dryer means. The filling capacity of the dried tobacco was then measured by a compressometer, in which pressure is applied to a piston within a cylinder and the volume of the tobacco is determined in milliliters (mls.) for a given weight of tobacco. Upon measuring filling capacity with the compressometer, the untreated tobacco measured 352 mls, while the same amount of tobacco puffed, with the hydrogen peroxide-catalase treatment measured 505 mls, thus showing a filling capacity increase of 40.4 percent.
EXAMPLE II A sample of tobacco was treated in exactly the same manner as in Example I using the same concentrations of hydrogen peroxide and catalase, except that after the cut tobacco was sprayed once with hydrogen peroxide and catalase, it was again immediately sprayed with the same amounts of hydrogen peroxide and catalase. After drying, the puffed tobacco measured 600 mls on the compressometer, compared to 358 mls for the untreated tobacco, which represented an increase of 55 percent in the filling capacity.
EXAMPLE Ill Examples I and II were repeated identically except that the hydrogen peroxide and catalase were added in the reverse order, according to the method of my previous US. Pat. No. 3,612,065. The increases in the filling capacities were virtually identical to those achieved in Examples I and ll. In Example I and the corresponding repeat of this example care was taken that the moisture content of the tobacco never exceeded 50 percent, and in Example ll and the corresponding repeat of this example, care was taken that the moisture content of the tobacco never exceeded percent.
EXAMPLE IV 100 volume hydrogen peroxide was diluted with distilled water to a concentration of 10 percent and catalase extract was diluted to a concentration of 1 percent. The hydrogen peroxide was sprayed onto the cut tobacco followed by spraying on of the catalase. After drying of the puffed tobacco, measurements were again made with a compressometer. The measurements showed an increase from 400 mls for the untreated tobacco to 700 mls for the puffed tobacco, or a percent increase in filling capacity. Moisture levels during the treatment never exceeded 50 percent.
EXAMPLE V Samples of tobacco were treated in the same manner as in Example IV using the same concentrations of hydrogen peroxide and catalase, except that an additional treatment with hydrogen peroxide and catalase in the same amounts was made after the first treatment. After puffing had stopped, the tobacco was dried and measured with a compressometer. Whereas the untreated tobacco had measured 400 mls, the treated tobacco measured 780 mls showing a filling capacity increase of 95 percent. The moisture levels of the tobacco during treatment never exceeded 70 percent.
EXAMPLE VI Two samples of the same type of tobacco leaf which was contaminated with beetle larvae were treated according to the process of the present invention and that of my previous U.S. Pat. No. 3,612,065. A percent solution of hydrogen peroxide was applied to the first sample and allowed to remain for 5 minutes. Then a 1 percent solution of catalase was applied to the hydrogen peroxide treated tobacco and puffing took place. After puffing, examination of the leaf showed that the larvae had been destroyed. The second sample of tobacco leaf was first treated with a 1 percent solution of catalase and then a 5 percent solution of hydrogen peroxide. Although virtually the same amount of puffing took place, the beetle larvae had not been completely destroyed.
EXAMPLE VII 100 volume hydrogen peroxide was diluted to 0.5 percent and a 0.5 percent solution of delayed catalase was also prepared. The catalase used had a 30 second delay period. The two solutions were mixed together in a container and cut lamina of tobacco were dipped into the mixture and coated with the liquid. The tobacco was quickly withdrawn from the liquid to react in the air. Moisture content of the tobacco due to dipping was about 50 percent, but upon being permitted to react in open air, evaporation of the liquid proceeded rapidly and drying time was about 5 minutes in a conventional dryer. Upon checking the filling capacity with a compressometer, the puffed tobacco was about 650 mls comparedto about 350 mls for the untreated tobacco.
EXAMPLE VIII the invention.
1. A method of treating tobacco comprising the steps of contacting said tobacco with an aqueous solution containing a given amount of hydrogen peroxide and providing on said tobacco a given amount of catalase, said hydrogen peroxide solution contacting said tobacco no later than said catalase, said given amount of catalase being effective to cause decomposition of said given amount of hydrogen peroxide and said given amount of hydrogen peroxide upon decomposition being effective to increase the volume of said tobacco.
2. A method according to claim 1 wherein said tobacco is first contacted with said hydrogen peroxide containing solution and thereafter provided with said catalase.
3. A method according to claim 1 wherein said hydrogen peroxide containing solution and said catalase are added to said tobacco simultaneously.
4. A method according to claim 3 wherein said catalase is a delayed catalase.
5. A method of treating tobacco according to claim 1 wherein said catalase is provided on said tobacco by providing a growth of yeast containing said given amount of catalase.
6. A method according to claim 1 wherein said given amounts are amounts less than that which will cause substantial rupture of the cell walls of said tobacco.
7. A method according to claim 5 wherein said yeast is applied to said tobacco in the fomi of an aqueous dispersion of said yeast.
8. A method according to claim 7 wherein said aqueous dispersion is sprayed on said tobacco.
9. A method according to claim 7 wherein said aqueous dispersion is applied by immersing said tobacco in the aqueous dispersion.
10. A method according to claim 7 wherein said aqueousdispersion contains in addition to said yeast, a nutrient for said yeast.
11. A method according to claim 5 wherein the yeast is applied to said tobacco as a dry powder.
12. A method according to claim 1 wherein said solution of hydrogen peroxide is an aqueous solution containing 3 to 30 weight percent of hydrogen peroxide.
13. A method according to claim 1 wherein said solution of hydrogen peroxide is 10-50 volume hydrogen peroxide.
14. A method according to claim 1 wherein said hydrogen peroxide solution is 20-40 volume hydrogen peroxide.
15. A method according to claim 1 wherein the amount of said hydrogen peroxide solution is sufficient to produce a volume of oxygen sufficient to oxidize a substantial portion of the nicotine in said tobacco.
16. A method according to claim 1 wherein said aqueous solution containing a given amount of hydrogen peroxide is formed by dissolving oxygen gas in distilled water and applying ultrasonic energy to the resulting solution to form hydrogen peroxide.
17. A method according to claim 16 wherein the ultrasonic energy is applied while tobacco to be treated is immersed in the water and oxygen solution.
18. A method according to claim 17 wherein the catalase is provided on said tobacco after the application of ultrasonic energy.
19. A method according to claim 1 wherein the treatment of the tobacco with hydrogen peroxide and catalase is repeated at least once.
t l k l