Method of treating tobacco with catalase and hydrogen peroxide

Abstract

A method of treating tobacco is described which involves the use of physical force to cause liquid containing catalase and hydrogen peroxide to permeate the interstices of the tobacco where they are reacted with each other in situ. Such reaction enhances properties of the tobacco, and in certain cases the volume of the tobacco is expanded. The physical force necessary to cause the treating material penetration may take the form of rollers, flat pressure means or continous expression means.

Parent Case Text

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my co-pending application Ser. No. 198,662, filed Dec. 20, 1971, now abandoned.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of treating tobacco, and more particularly relates to a method for improving the quality of tobacco and increasing its usefulness in the manufacture of smoking products.

2. Description of the Prior Art

In my U.S. Pat. No. 3,612,065, the disclosure of which is incorporated herein by reference and made a part hereof, I have described a method of treating tobacco wherein a given amount of catalase provided on said tobacco is reacted with a given amount of hydrogen peroxide in contact therewith, the mutual decomposition of catalase and hydrogen peroxide being effective to increase the volume of the tobacco up to 20 percent. Other prior art methods of treating tobacco to increase the volume thereof require the use of expensive solvents and complex solvent recovery systems. Some chemical solvents may affect the tobacco taste or leave a toxic residue.

Tobacco quality is determined by various objective and subjective factors, including the following:

1. Geographical source of the tobacco.

2. The portion of the tobacco plant used to form the tobacco product.

3. The moisture content of the tobacco.

4. The resistance to crushing of the tobacco.

5. The flavor of the tobacco.

6. The aroma of the tobacco before and during smoking.

It is known that as a result of importing certain foreign tobaccos importers and manufacturers are supplied with amounts of low quality tobacco, including both stems and lamina. These products may have a musty or ammoniacal odor and a sharp, peppery biting taste.

It is also known that conventional tobacco curing and ageing methods require from several months to several years in time in order to obtain desirable changes in the appearance, taste and aroma of the tobacco, as well as the smoke produced therefrom.

The less valuable forms of tobacco include the stems, ribs and stalks of the plant. However, these forms may be utilized in certain proportions for the production of acceptable smoking products. For example, it is well known that cigars are often made with a wrapper of one quality tobacco, a binder of another quality tobacco and a filler of still another quality tobacco. Obviously, the more less valuable tobacco product which can be incorporated into a highly rated tobacco product, the greater are the economies which may be expected. This same reasoning pertains to cigarettes since such product is filled with shredded tobacco, which is much more economically obtained from forms of tobacco such as stems, ribs, stalks and scraps than from the more expensive forms of tobacco.

The anatomical and chemical structure of tobacco may be exemplified by that of tobacco stems. Tobacco stem is herbaceous, consisting of pith, primary xylem, vascular rays and cortex. It is poor in collenchyma and rich in parenchyma, no cork being present. The cells are rectangular and their walls are thickened by the deposition of cellulose and pectin compounds. In cured stem all cells shrink together because of the rapid moisture loss, thereby reducing intracellular and intercellular space. However, the cells contain a great number of pores which permit the passage of gases.

It is accordingly an object of this invention to provide an improved method for treating tobacco with catalase and hydrogen peroxide.

It is another object of this invention to provide a method for treating tobacco more thoroughly than heretofore with agents for enhancing qualities of the tobacco.

It is another object of this invention to provide an improved method of expanding the volume of tobacco.

SUMMARY OF THE INVENTION

The objects of this invention have been achieved by the process of treating tobacco which comprises the steps of (1) evenly distributing on the surface of the tobacco a liquid solution containing catalase and a liquid solution containing hydrogen peroxide and (2) applying physical force to said tobacco to cause a portion of the hydrogen peroxide to permeate the interstices of the tobacco, whereby the catalase and hydrogen peroxide react on and within said tobacco. The selection of appropriate amounts of catalase and hydrogen peroxide will cause these reatants to mutually decompose. Where the physical force is removed from the tobacco prior to completion of the reaction of catalase and hydrogen peroxide, the gases produced by said reaction act to expand the volume of the tobacco.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The essential feature of the process of this invention is the carrying out of a reaction between catalase and hydrogen peroxide from within the interstices of tobacco. By so doing, the effects of said reaction are brought to bear more thoroughly on the tobacco constituents than by any other process known to me. By this means, I have been able to obtain increased expansion of tobacco and excellent flavor and aroma enhancement.

It will readily be apparent that the order of applying the catalase and hydrogen peroxide to the tobacco is not critical. A solution containing catalase may first be applied, then a solution containing hydrogen peroxide, or vice versa. Also, the catalase and hydrogen peroxide may be applied in the same solution, in which case a delayed catalase is preferred. Moreover, the catalase and hydrogen peroxide, if applied from separate solutions may be forced into the interstices of the tobacco at the same time, or one at a time.

The physical force may be applied to the wetted tobacco in many conventional ways such as by weighted flat plates, rollers, presses, or continuous expression devices. In a preferred embodiment of this invention, any excess liquid resulting from the application of physical force to the tobacco is prevented from again contacting the tobacco when the force is removed.

Since the catalase and hydrogen peroxide will mutually decompose proportionate amounts of themselves with the production of nascent oxygen, it is readily apparent that the physical force must be applied in a timely manner in order that the optimum effect of such reaction within the interstices of the tobacco is obtained. It is believed that the flavor enhancement obtained by the process of this invention is due to both sterilization of bacteria within the tobacco and chemical changes in the tobacco brought about by oxidation.

EXAMPLE 1

A 10 lb. sample of Pennsylvania cigar filler tobacco was treated by spraying an aqueous catalase (4 ml. catalase/1 l. water) solution onto the tobacco in an amount equal to 10 percent of the tobacco weight, and then spraying onto the tobacco a 27 percent hydrogen peroxide solution in an amount equal to 15 percent by weight of the tobacco. This treated tobacco was dried at 150.degree. F. and made into cigars. On smoking, these cigars had a foreign taste with no noticeable improvement over the taste of control cigars, both having an acrid, harsh taste. Some expansion of the tobacco was noticed.

EXAMPLE 2

Example 1 was repeated, except that immediately after the spraying of the hydrogen peroxide solution the tobacco was rolled with a heavy roller for a few seconds. When the rolling was stopped, the tobacco was seen to visibly expand to more than the volume of the treated tobacco from Example 1 and upon smoking showed considerable improvement in flavor over the control with a mildness that was described as being neutral.

EXAMPLE 3

Poor quality Phillipine flue cured cigarette strips were treated by spraying an aqueous catalase (4 ml. catalase/ 1 l. water) solution onto the tobacco in an amount equal to 10 percent of the tobacco weight, and then spraying onto the tobacco a 35 percent hydrogen peroxide solution in an amount equal to 5 percent by weight of the tobacco. This tobacco was dried and smoked with no noticeable change in flavor over the control which flavor was called undesirable to the industry by virtue of being overly sweet.

EXAMPLE 4

Example 3 was repeated, except that after the spraying of the catalase solution the tobacco was rolled with a heavy roller for a few seconds, and immediately after the spraying of the hydrogen peroxide solution the tobacco was again rolled with a heavy roller for a few seconds. Upon drying and smoking the overly sweet flavor had become more neutral and the tobacco had greater expansion.

EXAMPLE 5

Ten lbs. of cigar stems were sprayed first with 5 percent be weight of the tobacco of a 17 percent hydrogen peroxide solution and then sprayed with an aqueous catalase (3 ml. catalase/ 1 l. water) solution in an amount equal to 10 percent by weight of the tobacco. The stems were dried and smoked, whereupon they retained the papery acrid harsh flavor of the control. Some tobacco expansion over the control was noted.

EXAMPLE 6

Example 5 was repeated except that after the catalase spraying the stems were pressed by a flat weighted plate for a few seconds. This tobacco was dried and smoked, the flavor being defined as neutral and cigarette like. The tobacco had expanded more than the resultant product of Example 5.

EXAMPLE 7

Shredded cigarette lamina of low quality is placed in the wide end of a funnel having a central shaft with a helical screw surface formed thereon which closely conforms to the funnel. As the shaft is turned the tobacco is forced through the funnel being alternately compressed and released from the funnel. Before being forced through the funnel this tobacco is sprayed first with an aqueous catalase solution (4 ml. catalase/ 1 l. water) in an amount equal to 10 percent by weight of the tobacco and then sprayed with a 12 percent hydrogen peroxide in an amount equal to 5 percent by weight of the tobacco. After being forced through the expression device the tobacco was dried and smoked, having a mild smooth taste. The moisture content after expression was less than 22 percent.

EXAMPLE 8

Ten lbs. of a cigar tobacco was prepared by cutting 4-5 inch strips from the leaf. This tobacco was first sprayed with a 5 percent portion of 907 ml. of an aqueous catalase solution (3 ml. catalase/1 l. water), then sprayed with 907 ml. of a 6 percent hdyrogen peroxide solution to wet the tobacco 20 percent above its original moisture content, then sprayed with the remaining catalase solution. The thus sprayed tobacco was rolled with a heavy roller for a few seconds. The treated strips were bulked and placed in a curing room for 20 days, where the temperature was controlled to not more than 140.degree. F. The cured tobacco had a mild smooth sweet flavor and the leaves had obviously expanded.

EXAMPLE 9

10 lbs. of a cut blend of domestically grown lamina filler having a strong odor of ammonia and a sharp bite was obtained. This tobacco was first steamed. Then a portion of 680 ml. of an aqueous catalase solution (4 ml. catalase/1 l. water) was sprayed on the tobacco. Then 680 ml. of a 25 percent hydrogen peroxide solution was sprayed on the tobacco, followed by the remaining portion of the catalase solution. Then the sprayed tobacco was pressed by a weighted flat plate for several seconds, after which the tobacco was again steamed. The moisture level of the tobacco was never more than 29 percent during this treatment and it was easily dried. The resulting lamina when smoked had a smooth mild flavor and based on filling capacity showed an increased volume of 90 percent.

EXAMPLE 10

10 lbs. of whole stems were obtained. This tobacco was treated by (1) steaming well, (2) spraying with a portion of 907 ml. of an aqueous catalase solution (4 ml. catalase/1 l. water), (3) spraying with 907 ml. of 12 percent hydrogen peroxide, (4) spraying with the remainder of the catalase solution, (5) rolling the tobacco with a heavy roller for several seconds, (6) steaming well and (7) drying in a drier. When the thus treated tobacco was cut, rolled and smoked, it had a flavor which was sweeter and milder than a control, and the volume thereof had expanded three times.

EXAMPLE 11

101 lbs. of cut rolled burley stems was obtained. This tobacco was treated by (1) steaming well, (2) spraying with 680 ml. of an aqueous catalase solution (5 ml. catalase/1 l. water), (3) spraying with 680 ml. of 15 percent hydrogen peroxide solution, (4) rolling the tobacco with a heavy roller for several seconds, (5) steaming well, and (6) drying. Moistures did not exceed 30 percent during the process and upon smoking the flavor of the stems was mild and sweet. Expansion was 100 percent.

EXAMPLE 12

Cut stems were treated by wetting to a 40 percent moisture level with a combined spray of 1 percent hydrogen peroxide solution and a 1 percent aqueous delayed catalase solution. The sprays were combined above the tobacco and allowed to fall thereon. After spraying this tobacco was rolled for several seconds with a heavy roller, and then dried. The tobacco had a filling capacity of 150 per cent of control tobacco. Cigarettes were then made from this tobacco.

The cigarettes were conditioned for 25 hours at 75.degree. F. and 60% relative humidity. Smoking was done in a laboratory conditioned to 75.degree. F. and 60 R.H. The smoking system consisted of the cigarette, a tared Cambridge filter assembly and a smoking machine that produces a 35 ml. puff of 2 second duration at a rate of one puff per minute. All cigarettes were smoked to a butt length of 3 mm longer than the tipping paper. Five cigarettes were smoked through each Cambridge filter and the results calculated and reported in terms of one cigarette.

Moisture was determined by gas chromatography according to a procedure described in a paper entitled "Determination of Moisture in Total Particulate Matter" by Schultz and Spears in Tobacco Science, Vol. X, pp. 75-76 (1966).

As soon as the filter assembly had been weighed to determine total particulate matter, it was opened and the filter holder was then wiped with one-fourth of a Cambridge filter pad and this added to the bottle. Ten ml. of dry dioxane-isopropanol 100:1) was measured from an automatic burette into the serum bottle and the stopper inserted. The bottle was shaken for 20 minutes on a Wrist Action shaker.

A sample of 5 microliters was withdrawn with a Hamilton syringe through the rubber serum cap and subjected to gas chromatography in an Aerograph 90-p3 gas chromatograph. The moisture content of the particulate matter was read from a calibration curve made by adding known amounts of water to the solvent mixture. Cigarettes conditioned at 75.degree. F. and 60% R.H. were treated in the same manner and the average value of the moisture content subtracted from the amounts found to get the net moisture content.

The balance of the solution for GlC moisture, plus the filter pad, was transferred to a Griffith still and the nicotine determined by the usual procedure of double distillation and reading at three wave lengths in an ultraviolet spectrophotometer.

The results of these tests were as follows:

Total Particulate Control Moisture Nicotine Tar ______________________________________ 27.5 2.1 1.43 20.0 27.2 1.7 1.41 20.7 25.7 2.3 1.39 19.8 25.8 1.5 1.45 20.2 Average 26.6 1.9 1.42 20.2 25% puffed material in cigarette 9.2 2.1 .59 8.4 9.8 1.6 .70 8.5 10.5 2.2 .70 9.6 8.7 1.4 .52 8.2 Average 9.5 1.8 .63 8.4 75% puffed material in cigarette 4.1 2.1 .22 4.1 4.2 1.6 .30 4.0 5.2 2.2 .29 4.1 4.3 1.4 .21 3.8 Average 4.4 1.8 .25 4.0 ______________________________________ Average number of puffs for all groups was 10 Butt length 27mm Average pressure drop 6.1 inches -

EXAMPLE 13

Separate lots of cut rolled tobacco stems were treated by first spraying the tobacco thoroughly with a 3% by weight acqueous hydrogen peroxide solution and then with an acqueous solution of catalase, both solutions being applied at a rate of 250 ml. of solution per pound of tobacco. The treated tobacco was then rolled for several seconds with a heavy roller and then dried. Each lot was blended with tobacco lamina to give 75% lamina/25% cut rolled stems blends. Comparable blends of untreated cut rolled stems and lamina were prepared as a control, and all of the blends made into cigarette samples and tested as follows:

Table No. 1A __________________________________________________________________________ UNTREATED TREATED REQUIRED C.R.S. 130 c/i C.R.S. 227 c/i C.R.S. 130 c/i C.R.S. 227 __________________________________________________________________________ c/i Moisture content before treatment % -- -- 18 18 __________________________________________________________________________ Used H.sub.2 O.sub.2 concentration % -- -- 3 5 10 3 5 10 Total Moisture Content after H.sub.2 O.sub.2 application % -- -- 32.+-. 2 32.+-. 2 32.+-. 2 32.+-. 32.+-. 32.+-. 2 Total Moisture content after Enzyma application (finished treatment) % -- -- 46.+-. 2 46.+-. 2 46.+-. 2 46.+-. 46.+-. 46.+-. 2 Used Drying Temp. .degree.F. -- -- 140.+-. 5 140.+-. 5 140.+-.5 140.+-. 140.+-. 140.+-.5 Moist. content after 48 hrs. conditioning at 76.degree.F. -- 68% R.H. % 16.4 16.2 17.6 17.5 17.4 17.5 17.5 17.5 Compression m/m 6.60 8.98 4.37 2.32 1.59 4.84 3.58 1.88 Column Height m/m 23.40 22.02 25.63 27.68 28.41 25.16 26.42 28.12 Used Quantity: g. of C.R.S. 20 20 20 20 20 20 20 20 Expansion % -- -- 9.5 18.3 21.4 14.2 20 27.7 __________________________________________________________________________

Table 1B __________________________________________________________________________ UNTREATED TREATED C.R.S. 130 c/i C.R.S. 227 c/i C.R.S. 130 c/i C.R.S. 227 c/i Moisture content before treatment % -- -- 18 18 Used H.sub.2 O.sub.2 concentration % -- -- 3 5 10 3 5 10 Total Moisture Content after H.sub.2 O.sub.2 application % 32.+-. 2 32.+-. 2 32.+-. 2 32.+-. 32.+-. 32.+-. 2 Total Moist. content after Enzyma application (finished treatment) % -- -- 46.+-. 2 46.+-. 2 46.+-. 2 46.+-. 46.+-. 46.+-. 2 Used Drying Temp. .degree.F. -- -- 140.+-. 5 140.+-. 5 140.+-.5 140.+-. 140.+-. 140.+-.5 Moisture content after 72 hrs. conditioning at 73.degree.-- 65% R.H. % 12.50 12.80 14.0 13.6 13.6 13.9 13.7 13.8 Compression Height MM 8.24 9.27 4.40 2.52 1.04 4.26 3.48 2.36 Column Height MM 21.76 20.23 25.60 27.48 28.96 25.74 26.52 27.64 Used Quantity of C.R.S. g. 15 15 15 15 15 15 15 15 Expansion % -- -- 17.6 23.3 33.1 27.2 31.1 36.6 __________________________________________________________________________

Table 1C __________________________________________________________________________ Cigarettes Blends Cigarettes Blends Untreated Treated __________________________________________________________________________ Cont. 25% Untr. Cont. 25% Untr. Cont. 25% Treat Cont. 25% Treat. C.R.S. 130 c/i in C.R.S. 227 c/i in C.R.S. 130 c/i in C.R.S. 227 c/i in 75% Lamina only 75% Lamina only 75% Lamina only 75% Lamina __________________________________________________________________________ only Moisture Content in CRS LAMINA CRS LAMINA CRS LAMINA CRS LAMINA C.R.S. And Lamina at 18 16 18 16 18 16 18 16 Blending time % Used H.sub.2 O.sub.2 Concentra- tion % -- -- -- -- 3 -- 3 -- Blends Moist. Contents After 72 hrs. conditioning at 73.degree.F. 65% R.H. 14.3 14.4 14.6 14.4 Compression MM 5.98 5.84 2.92 2.96 Column Height MM 24.02 24.16 27.08 27.04 Used Quantity of Blend: g. 20 20 20 20 Expansion % -- -- 13 12 __________________________________________________________________________

Table No. 2 __________________________________________________________________________ Samples Cgt. Wt. Moisture Diameter Compression Filling Expansion Description g. % m/m m/m Index g. % __________________________________________________________________________ Control 130 c/i 1.1570 14.00 7.93 5.54 1.0381 +9 Sample 130 c/i Treated with 3% 1.1568 14.56 7.93 5.59 0.9404 H.sub.2 O.sub.2 Control 227 c/i 1.1582 14.20 7.98 5.52 1.0413 +8 Sample 227 c/i Treated with 3% 1.1540 14.37 7.90 5.58 0.9563 H.sub.2 O.sub.2 __________________________________________________________________________

Table No. 3A ______________________________________ Sample P.D. T.P.M. NICOTINE Description cm. mg. mg. ______________________________________ Control 130 c/i 12.2 20.87 0.91 Sample 130 c/i Treated with 3% 13.2 20.03 0.89 H.sub.2 O.sub.2 Control 227 c/i 11.3 22.57 1.07 Sample 227 c/i Treated with 3% 12.8 21.09 1.02 H.sub.2 O.sub.2 ______________________________________

Table No. 3B __________________________________________________________________________ Sample Cgt. wt. Moisture Cold Warm Collapsing Description g. % Compression Compression Index m/m m/m m/m __________________________________________________________________________ Control 130 c/i 1.1570 14.00 4.47 4.47 1.07 Sample 130 c/i Treated with 3% H.sub.2 O.sub.2 1.1568 14.56 5.59 4.49 1.10 Control 227 c/i 1.1582 14.20 5.58 4.50 1.08 Sample 227 c/i Treated with 3% H.sub.2 O.sub.2 1.1540 14.37 5.52 4.42 1.10 Repeat Control 227 c/i 1.2400 14.3 5.42 4.35 1.07 Sample 227 c/i Treated with 3% H.sub.2 O.sub.2 1.160 14.2 5.64 4.53 1.11 __________________________________________________________________________

When cigarettes from the treated samples are smoked, a concrete mild smooth sensation can be detected. This is surprising since cut rolled stems as a cigarette filler is a very rich-in-cellulose component which contributes directly to the organoleptic qualities of smoke, and which when added to leaf tobacco normally gave the smoke a harsh quality readily detected by the smoker. Referring to Tables 1A, 1B and 1C, effective increases in filling values are shown for the treated lots of cut rolled stems and their blends with lamina. Results of blends made into machine made cigarettes are shown in Table 2. Referring to Table 3A, smoking tests showed no significant differences on T.P.M. and nicotine between the treated cigarettes and the controls. Referring to Table 3B, no significant differences between the collapsing indexes of the treated cigarettes and the controls were found.

EXAMPLE 14

A quantity of Virginia leaf tobacco was obtained. Certain leaves were randomly selected and separated into two groups of leaves. The first group was subjected a conventional flue curing process and yellowed at 35.degree.C and 85% R.H. These leaves were then progressively dried under gradually elevated temperatures to 78.degree.C over a 48 hour period. The second group of leaves was treated by first spraying with simultaneously with a mixture of 0.5% by weight acqueous solutions of hydrogen peroxide and delayed catalase. Before significant reaction occurred these treated leaves were rolled for several seconds with a heavy roller. When no further reaction was apparent, the tobacco of this group appeared bright in color.

Following drying of the separate groups, samples were conditioned for handling.

Prior to cigarette manufacture, tobacco from various leaf positions within each group was composited and uniformly blended. Cigarettes 85mm in length were prepared using 32 cuts/inch. Cigarettes were selected having the same draw resistance.

Smoking Procedure and Chemical Examination of the Smoke

The cigarettes were moisture equilibrated at 65% relative humidity and 25.degree.C. The cigarettes prepared from the hydgrogen peroxide-catalase process were selected to weigh 835 mg and the cigarettes made from the conventionally cured tobacco were selected to weigh 835 mg.

The two types of cigarettes were smoked mechanically on a Phipps and Bird machine using Cambridge Filters for trapping the particulate matter (puff volume 35 ml, puff duration 2 sec., puff frequency 1 puff/min., butt length 23 mm). The determination of the amount of total particulate matter and its water content were performed according to the Coresta standard method No. 10. The amount of nicotine was determined by the Coresta standard method No. 12. The determination of phenol in the particulate matter which accounts for 97 per cent of total smoke phenol value was accomplished using a method of Williamson modified by Carlson, which is based on spectroscopic determination (480nm) after treatment of the separated acidic material with diazotized p-nitroaniline. The results of these determinations are as follows:

Flue Cured H.sub.2 O.sub.2 -Catalase ______________________________________ Weight of tobacco mg./cig. 835 835 Average number of puffs/cig. 9.0 9.0 Total particulate matter TPM 48.9 15.1 Increase in filling capacity (% in sample) 50% Nicotine m/cig. 3.4 .7 Phenol mg/cig. 345 97 Sugars (%) 9.68 15.2 ______________________________________

EXAMPLE 15

Cut lamina was sprayed with a mixture of a 2% by weight acqueous hydrogen peroxide solution and a 1.5% by weight acqueous catalase solution ((having a delay of 3 minutes) up to 20% by weight moisture level. This lamina was then rolled with a heavy roller for several seconds and allowed to dry. The filling capacity of this treated lamina was 990 milliliters. Cigarettes were made from the untreated lamina and 75% treated lamina -- 25% untreated lamina and 25% treated lamina -- 75% untreated lamina, and tested as follows:

Smoking Conditions and Collection of Tar

Twenty cigarettes were smoked for each set of determinations. These were smoked to an approximate 23 mm butt length using a CSM-10 Smoking Machine. A 35ml puff of 2 seconds duration was taken once a minute on each cigarette. The smoke was collected at room temperature in 50ml. of vigorously stirred cyclohexane contained in a 250 ml. flask. Addition of the smoke beneath the surface of the cyclohexane was avoided to eliminate a possible pressure drop. Collection of smoke in this manner was very efficient. During the smoking of groups of 20 cigarettes no significant amount of particulate matter deposited on a Cambridge filter which was placed behind the collection flask in the smoking train.

After the smoke was collected, the cyclohexane solution was transferred to a separatory funnel. The collection flask, stirrer, and inlet tube were rinsed with alternate portions of 2.times.5 ml. of 0.5 N sodium hydroxide and 3.times.5 ml of cyclohexane. After removing the aqueous layer, the cyclohexane solution was extracted with 3.times.5 ml. of 0.5 N sodium hydroxide followed by 1.times.5 ml. saturated NaCl sodium chloride. The extracts were combined and backwashed with 2.times.5 ml. of cyclohexane. This base extract was used to determine phenols. The combined cyclohexane solution was extracted with 5.times.5 ml. of 0.5 N hydrochloric acid followed by 1.times.5 ml. of saturated sodium chloride. The extracts were combined and backwashed with 2.5 ml of cyclohexane which was added to the main cyclohexane solution. This acid extract was used for the determination of nicotine.

The cyclohexane solution was next extracted with 5 ml. of methanol water (4:1). After separation the methanol-water solution was backwashed with 2.10 ml. and 4.5 ml. of cyclohexane which was added to the main cyclohexane solution. The cyclohexane solution was next extracted with 2.10 ml. and 6.5 ml. of nitromethane. These nitromethane extracts were combined and the solution concentrated to dryness using a rotary evaporator (bath temp. 45.degree.C; press. 30 mm.). The residue was used for the determination of benzo-a-pyrene.

Determination of Phenols

The base extract was steam distilled. Approximately 500 ml. of distillate was collected and discarded. The contents of the distillation flask were allowed to cool and then acidified with 50 ml. of 20% sulfuric acid and again steam distilled. The distillate (180ml.) was acidified and extracted with 6.50 ml. of purified ether. The ether extracts were combined and extracted with 2.5 ml. of saturated sodium bicarbonate solution. The ether solution was dried over anhydrous sodium sulfate and concentrated to less than 1 ml. by distillation through a 13 cm. Vigreux column at atmospheric pressure. This concentrated ether solution was transferred to a 1 ml. volumetric flask and diluted to volume. This solution was used to determine phenols by gas chromatography, using a Barber-Coleman Selecta 5000 system with a model 5043 electrometer and a flame ionization detector. A 2m.times.1/8 in. s.s. column packed with 100-120 mesh Parapak Q was used.

The operating parameters were: nitrogen carrier gas flow 25 ml./min; air and hydrogen gas flows, 300 ml. and 27 ml./min respectively; column, injector and detector temperatures, 230.degree., 250.degree., and 270.degree.C, respectively. The electrometer settings were: sensitivity, 10.sup.10 amps and attenuation, 2. An Infotronics Digital Readout System, Model CRS-11 HSB, was used to determine peak areas. The settings on the integrator were: tracking rate, 3 up--10 down; threshold level, 0.05; trip, 4; slope sensitivity, 1; and filter frequency, 1.

The concentration of Phenol, o-cresol, and m- and/or p-cresol was determined from the ratio of their individual peak areas to the area of o-chlorophenol which served as an interanal standard. An aliquot of a standard solution containing 2 mg. of o-chlorophenol was added to the cyclohexane solution immediately after the smoke was collected. The relative response and retention time of the phenols to o-chlorophenol were determined from a standard solution containing phenol, o-, m-, p-cresol and o-chlorophenol.

Determination of Nicotine

This procedure is a modification of that described by Ogg for the determination of nicotine in smoke particulate matter collected on a Cambridge Filter. The acid extract and 10 ml. of 0.5 N hydrochloric acid were steam distilled until 300-400 ml. of distillate was collected, which was discarded. After the acidic solution in the distillation flask had been allowed to cool, 30 ml. of a 30% sodium hydroxide solution, saturated with sodium chloride, was added. The resulting solution was then steam distilled until approximately 400 ml. of distillate was collected. In this second distillation the distillate was collected under the surface of 50 ml. of 0.5 N hydrochloric acid contained in a 500 ml. volumetric flask. After the volume of the distillate was adjusted to 500 ml. with distilled water, a 25 ml. aliquot was diluted to 100 ml. with 0.05 N hydrochloric acid. The absorbance of this solution was read at 236 mu, 259 mu, and 282 mu Milligrams of nicotine per cigarette, N, was calculated using the formula:

N = A.sub.259 - (A.sub.236 + A.sub.282)/2/0.3213 .times. b,

where A.sub.236, A.sub.259 and A.sub.282 are the absorbances at the indicated wavelengths and B is the pathlength of the cell in cm.

Determination of Benzo-a-pyrene

The residue from the nitromethane-soluble fraction was dissolved in approximately 20 ml. of benzene, placed on a 2.5 cm. column containing 5 grams of silicic acid and the column was eluted with 250 ml. of benzene which was collected in a single portion. This procedure removed the bulk of the polar chromophoric material. The eluant which contained the benzo-a-pyrene and other aromatic hydrocarbons was concentrated to dryness using a rotary evaporator (bath temp. 45.degree.C, press 30mm.). The weight of this residue is reported as the nitromethane fraction. After the residue was weighted it was taken up in approximately 0.1 ml. cyclohexane and applied as a series of spots, forming a 12 cm. streak, to a 20.times.20 cm alumina thin-layer plate. Reference spots of authentic benzo-a-pyrene were placed 1.5 cm from each end of the streak. After the plate was developed in ethyl etherpentane, the band containing benzo-a-pyrene was located by examining the plate under UV light and was transferred to a 15 ml. centrifuge tube. The benzo-a-pyrene was desorbed with 4.times.4 ml. methanol. The four solutions were combined and concentrated to approximately 0.1 ml. and chromatogrammed on a 20% acetylated cellulose thin-layer plate. After the plate was developed in ethanol-toluene-water (17:4:1), the benzo-a-pyrene band was transferred to a 15 ml. centrifuge tube and recovered by desorbing with 4.times.4 ml. of methanol. All methanol solutions were pooled, concentrated to approximately 0.3 ml., and filtered through a small cotton plug into a volumetric flask. After dilution to 2 or 5 ml. the fluorescence spectrum of the solution was obtained, using an Aminco-Bowman Spectrofluorometer set at an excitation wavelength of 380 mu. The fluorescence maximum at 405 mu. was read and the concentration of benzo-a-pyrene was determined with a standard curve.

Determination of Total Particulate Matter

Total particulate matter was determined from five cigarettes essentially as described by Ogg. The cigarettes were smoked to a 23 mm. rather than a 30 mm. butt length.

Determination of Burn Temperature

Temperature measurements were made using a 0.012 inch diameter Pt/Pt --13% R.H. thermocouple connected in series with a reference junction (0.degree.C) to a potentiometer type recorder. The thermocouple was inserted approximately 25mm. into the free end of the cigarette which was held in a Cambridge filter holder. The burn temperature was recorded as the point of maximum recorder response as the combustion zone passed over the thermocouple junction. For each determination 10 cigarettes were smoked, using a standard smoking cycle, and the values averaged.

______________________________________ Puffed samples control ______________________________________ 75% 25% Average 2/cig. (g) 1.17 1.17 1.17 Percent moisture 10.0 12.1 12.1 No. puff/20 cig. 218 218 218 Average Burn temp (.degree.C) 497 668 878 Analysis of Cig. Smoke per cig. Wet TPM (mg) 7.0 20.3 29.8 Dry TPM (mg) 4.2 17.1 28.2 Nicotine (mg) .09 .87 1.40 Benzo-a-pyrene (mg) .61 7.3 11.5 Phenol (mg) 3 54 83 o-cresol (mg) .7 8 15 m-, p-, cresol (ug) 5 24 35 Total phenols (ug) 10 78 133 per 100 ml. smoke Dry TPM (mg) .52 4.2 7.8 nicotine (mg) .53 .21 0.37 Benzo-a-pyrene (mg) .005 1.9 3.0 Phenol (ug) .03 14 22 o-cresol (ug) .04 2 4 m, p-cresol (ug) .02 7.5 9 Total Phenols (ug) .05 20 35 ______________________________________

EXAMPLE 16

A mixture of equal parts of a 0.5% by weight aqueous hydrogen peroxide solution and a 0.5% by weight aqueous catalase (2 min. delay) solution was prepared. To this solution was added an equal amount of ethanol. Cut lamina was wetted thoroughly by a spray of this hydrogen peroxide-catalase-alcohol solution. The wet lamina was then rolled for several seconds with a heavy roller and then subjected to an air stream at a temperature of 100.degree.F for 2 minutes. The material was then dried in a vacuum drier for 15 minutes. The dried tobacco product had a filling capacity of 1,020 milliliters. Cigarettes were made from this treated tobacco in varying proportions with respect to the control tobacco. Each cigarette contained 1 gram of tobacco and was 85 mm. in length. All of the cigarettes then were tested by smoking in a constant volume smoking machine using the following conditions: -- puff volume, 35 ml.; puff duration, 2 sec.; puff frequency, 1 per min.

Tests were then made of the tobacco smoke to determine the presence of ethane, ethylene, methanol, acetaldehyde, acetonitrile, acrolein and acetone in the smoke composition.

Moisture determinations were performed by a modification of the Carl Fischer Method and with the Ohaus Moisture Balance, both of which gave comparable values.

Temperature measurements were made using a Pt/Pt -- 13% R.H. thermocouple of either 0.001 or 0.002 in. diameter. For combustion temperature measurements, the thermocouple was inserted perpendicular to the longitudinal axis of the cigarette at a point 15mm. from the front end. The results of these tests were as follows:

Mol % ______________________________________ Burn Temp. CO Methane Ethane Ethylene ______________________________________ 100% P.T.* 480C .87 0.02 .0008 .0001 75% P.T. 510 .98 0.05 .0012 .0005 50% P.T. 580 1.10 0.09 .0123 .0025 25% P.T. 670 2.20 0.15 .0319 .0149 control 849 3.00 0.43 .0805 .0389 ______________________________________ *puffed tobacco

Mcg./l. __________________________________________________________________________ Acetal- Aceto- Acro- Burn Temp. Methanol dehyde nitrile lein Acetone __________________________________________________________________________ 100% P.T. 480C 4.1 7.2 .09 .08 2.1 75% P.T. 510 7.4 10.7 2.40 1.50 4.2 50% P.T. 580 10.2 14.6 3.82 2.81 8.0 25% P.T. 670 18.3 24.2 6.91 4.32 12.5 control 849 36.1 74.0 14.32 9.21 40.6 __________________________________________________________________________

Sampling Procedures

All analytical data were obtained on the fifth puff of the cigarette. The puffing sequence was controlled by a preset timer (Dual-Trol), such that the interval between puffs was 60 seconds and the duration of the puff 2 seconds. Lighting the cigarette constituted the first puff. A fresh Cambridge filter was used for each cigarette to separate the particulate phase from the vapor phase.

For colorimetric analysis reagent solution was injected into a dismantled collection flask with a syringe. The flask stopcocks were then closed, and the flask inserted into a wet ice-bath and connected to the smoking machine manifold. At the end of the fourth puff, the sample flask was opened to the manifold and evacuated. After 45 seconds, the stopcock on the vacuum line was closed and after 60 seconds, a puff of smoke was automatically puffed into the flask during the second interval. The flask was then closed, removed, and its contents thoroughly shaken prior to colorimetric analysis.

For gas chromatographic analysis aliquots of the smoke gas were extracted from the manifold by means of sampling values and admitted immediately into the carrier gas stream of the chromatographic column. The volume of gas admitted to the column was regulated by the length of loops on the sampling values.

Determinations were based on measurements of peak heights; peaks were characterized by retention time comparisons and chromatography with standard mixtures of known compounds. Methane and CO -- 10 ft. and 0.25 in. o.d. column of 40-60 mesh molecular sieve 13x; flow rate 125 ml/min. ambient column temperature; thermal conductivity detection. Acrolein, acetonitrile, acetaldehyde, acetone and methanol-10 ft. .times. 0.125 in. o.d. column of Polypak 11; flow rate 45 ml./min., column temperature programmed from 50 - 170 c. at 3.5/min. and from 170 - 225 C. at 2.8/min., hydrogen flame detection.

EXAMPLE 17

Cut lamina was wetted thoroughly by spraying with a mixture of equal parts of 0.5% aqueous solution of hydrogen peroxide and isopropanol. This lamina was then rolled for several seconds with a heavy roller and then immersed in liquid nitrogen. Upon removal from the liquid nitrogen the lamina was wetted with a 0.5% aqueous solution of catalase and then rolled again for several seconds. This material was then vacuum dried for 10 minutes. Measurement of the filling capacity of the thus dried tobacco showed 805 milliliters. Fifteen experimental cigarettes were made using 35% of this treated tobacco and 65% cut lamina control. These experimental cigarettes were compared with 15 commercial Kool cigarettes by smoking each in lots of five cigarettes each. The CO content of the mainstream smoke was determined Smoking conditions were as specified by the current Federal Trade Commission regulation, 2-sec. 35-ml. puffs at 1 minute intervals in a laboratory controlled to 75%F. and 60% Rh. The following data were obtained: Carbon Monoxide mg./liter Vol. % ______________________________________ Kool commercial Lot 1 59 5.2 Lot 2 58 5.1 Lot 3 60 5.3 Average 59 5.2 Experimental Lot 1 22 1 Lot 2 22 1 Lot 3 22 1 Average 22 1 ______________________________________

The average reduction in CO effected by the puffed tobacco process using 35% puffed material in these cigarettes is 80%.

Hydrogen peroxide, utilized in accordance with the process of this invention will not leave toxic residues in the tobacco. Moreover, it is well known that hydrogen peroxide is used medically as a sterilizer and in many food products to eliminate bacteria and other organisms. Also in accordance with the process of this invention, catalase and hydrogen peroxide are mutually decomposed, leaving no amount of either reactant. Peroxide-catalase treatment of milk for cheesemaking is known, as is peroxidase-catalase treatment of liquid egg products.

The fact that flavor of tobacco may be enhanced by the process of this invention is believed to be due to the fact that the extremely large amount of nascent oxygen evolved upon decomposition of hydgrogen peroxide acts to oxidize substances within the tobacco as well as to expand the tobacco. The resulting milder, smoother tastes are considered to be the consequence of a breakdown of polysaccharide chains such as starch and cellulose composed of glucose residues which are the main constituents of the cell walls of the tobacco leaf.

It will be apparent that there is no theoretical limit on the amounts of hydrogen peroxide and catalase used, since the process of this invention is shown to be effective at levels at least as low as 0.5% by weight concentrations. Increased mutually decomposing amounts of catalase and hydrogen peroxide bring about greater recognized effects, such as expansion, but the upper limits of catalase and hydrogen peroxide are only economic.

It will moreover be appreciated that advantages accrue to the process of this invention when the hydrogen peroxide is made more concentrated from an aqueous solution while it is on and within the tobacco. Examples of the means for accomplishing this concentration are contacting the peroxide wetted tobacco with cold gaseous or liquid nitrogen, heated air, ultraviolet radiation and/or vacuum drying.

Once the hydrogen peroxide has been concentrated it is then contacted by catalase in its normal or delayed form in order to puff the tobacco. Various inhibitors can be used to delay the catalase including citric acid and alcohol.

The advantages of concentrating the hydrogen peroxide are one of economy and efficiency. For instance, a lesser concentration of peroxide may be used to wet the tobacco, but when concentrated can double or triple in strength. The greater the strength of the peroxide, the greater the expansion of the tobacco when contacted with catalase. Also concentrated peroxide will mix better with the catalase when contacted in that there is less water present creating a maximum of the treating materials. This helps to eliminate excess moisture and insures quicker drying. Furthermore, the peroxide will penetrate down into the tobacco and concentrate in the cells so that when catalase hits the tobacco surface the reaction will spread down into the tobacco expanding it to its maximum.

The method of applying the nitrogen and alcohol is by spraying or immersion or other feasible methods or by passing an air stream over the tobacco as in the case of heated air.

It is also possible although not a preferred method to first treat the tobacco with nitrogen gas or liquid, alcohol or heated air. The hydrogen peroxide may then be applied. It will then concentrate although not as efficiently. The tobacco may also be treated by a series of treatments of either the nitrogen liquid or gas, alcohol, heated air, ultraviolet light, or vacuum drying. For instance, the tobacco may be sprayed with liquid nitrogen, then soaked in hydrogen peroxide, then contacted with catalase and then heated air passed over it.

The tobacco may also be treated with hydrogen peroxide by spraying, immersed in nitrogen and contacted with catalase and then vacuum dried.

The tobacco may be sprayed with hydrogen peroxide, vacuum dried to concentrate, and then contacted with catalase.

The tobacco may also be treated with a mixture of hydrogen peroxide and delayed catalase placed on the tobacco with alcohol as a carrier. This tobacco will then be contacted with heated air under 140.degree. to concentrate the peroxide and volatilize the alcohol. The catalase already present in the mixture will then react with the concentrated peroxide.

The tobacco may also be treated with hydrgen peroxide and alcohol and sprayed with liquid nitrogen to concentrate, contacted with catalase and then vacuum dried.

Another method of treatment is to freeze the hydrogen peroxide on the tobacco and then contact it with liquid nitrogen to stabilize and concentrate the hydrogen peroxide. The tobacco will then be contacted with catalase to reactivate the hydrogen peroxide and then dried with heated air.

The alcohols used may be of the type that is non-toxic for use on tobacco such as ethanol, isopropanol and butanol.

While I have disclosed the use of the process of this invention with respect to various naturally occurring forms of tobacco, such as leaf, stems and ribs, it will be readilly apparent that a finished product such as reconstituted tobacco sheet may likewise be treated in accordance with the process of this invention to achieve the desirable advantages thereof.

EXAMPLE 18

A finished homogenized tobacco sheet is sprayed with equal parts of a 27 per cent by weight aqueous hydrogen peroxide solution and an aqueous catalase (4 ml catalase/1 water) solution in order to increase the moisture content of the sheet by 20 per cent of its weight. The wet sheet is immediately pressed with a heavy roller in order to cause the solutions to penetrate interstices of the sheet. The sheet was then dried. After drying the sheet was found to be more porous than originally and a cigarette incorporating the shredded sheet was judged to be milder than a cigarette incorporating untreated sheet.

One advantage gained by treating reconstituted tobacco sheet by the process of this invention is the sufficient modification of the tobacco flavor to enable a smoking article to be produced utilizing solely reconstituted tobacco sheet as filler. This is an important industrial factor since the amounts of reconstituted tobacco sheet utilized in commercial American cigarettes rose to a level of 15 per cent of the total filler in 1964.

Additionally, many forms of reconstituted tobacco sheet are formed with high densities. By use of the process of this invention, finished reconstituted tobacco sheet may be provided at a lower density than heretofore allowing more air penetration of the tobacco article and therefore lower burn temperature. It has also been observed that lower density sheet may become stronger with respect to the liklihood of tearing when used to wrap or bind cigars or cigarettes. Moreover, such products have increased hygroscopicity, leading to products with longer shelf lives and stability.

Claims

Having thus described my invention, I claim:

1. A method of treating tobacco to improve its flavor and expand the tobacco, comprising the steps of substantially evenly distributing on the surface of the tobacco catalase and a liquid solution containing hydrogen peroxide, the amounts of catalase and hydrogen peroxide being sufficient to mutually decompose each other, and before significant reaction between these two components obtaining, applying physical force in the form of pressure means selected from the group comprising roller means, flat pressure means, and continuous expression means to said tobacco to cause catalase ahd hydrogen peroxide to permeate the interstices of the tobacco, whereby the catalase and hydrogen peroxide react in situ on and within the tobacco.

2. The method in accordance with claim 1, wherein the physical force is removed from the tobacco prior to the completion of the reaction of catalase and hydrogen peroxide, thereby allowing volumetric expansion of the tobacco.

3. The method in accordance with claim 1, wherein a catalase solution is first applied and then a hydrogen peroxide solution is applied.

4. The method in accordance with claim 1, wherein a hydrogen peroxide solution is first applied and then a catalase solution is applied.

5. The method in accordance with claim 1, wherein step (1) comprises applying a liquid solution containing both catalase and hydrogen peroxide on the surface of the tobacco.

6. The method in accordance with claim 5, wherein the catalase is delayed catalase.

7. The method in accordance with claim 1, wherein the tobacco is uncured tobacco.

8. The method in accordance with claim 1, wherein the tobacco is cured tobacco.

9. The method in accordance with claim 1, wherein the tobacco is whole leaf tobacco.

10. The method in accordance with claim 1, wherein the tobacco is tobacco lamina.

11. The method in accordance with claim 1, wherein the tobacco is tobacco cut ribs and stems.

12. The method in accordance with claim 1, wherein the tobacco is finished reconstituted tobacco sheet.

13. A method according to claim 1 wherein during the treatment of the tobacco the moisture content of the tobacco does not exceed about 46 weight percent of the tobacco.