Describes laboratory studies in which "substantial increases in smoke pH and smoke impact [were] obtained by the application of certain calcium and potassium compounds" that naturally occur in tobacco. Proposes proper application of compounds "could be useful for improving cigarette impact and thus, consumer satisfaction." Notes that supplementation of naturally occurring compounds to increase alkalinity in cigarettes would eliminate need for "extensive toxicity studies."
Recipient: Patterson, R.B.; Barnes, Winston; Lewis, C.I.; Sklanaowski, M.A.
Smoke constituent: Citric acid; Oxalic acid
Additive: Potassium hydroxide; Lithium hydroxide; Potassium nitrate; Calcium oxide; Calcium lactate; Potassium citrate; Ammonium phosphate
- Ihrig, Arthur M. (LOR Sr. Research Chemist, c.1983)
- Tucker, Charles. L., Jr. (Lor, Product Development Manager, 1979-1983)
- Jessup, T. D. (PM Nicotine Manipulation)
- Hudson, Albert B. (Lor, Exp. Products Anal. Chemist, 1965)
- Schultz, Frederick J., Ph.D. (VP of Lorillard, Inc. '89-95)
- Nicotine transport, transfer, and uptake
Design changes which alter nicotine delivery or effect how the product causes and maintains dependence, including transfer of nicotine from tobacco to smoke, and uptake into the body.
- Use of additives
Modification of tobacco products through use of additives and measuring effects on dependence, behavior, and toxicity.
- Free Nicotine
- Use of tobacco processing/ blends
Modification of tobacco products through changes in tobacco processing and use of blends, and measuring effects on dependence, behavior, and toxicity.
- Impact (Throat grab)
- Free nicotine (Unprotonated or unionized nicotine)
- Potassium carbonate
- Smoke Constituent
- Design Component
- Maryland tobacco
- Burley tobacco
- Flue-cured tobacco
- Named Organization
- Lorillard Inc. (American cigarette manufacturer)
American cigarette manufacturer
- Target/Low-Income (Target Groups)
- Sensory Effects—Impact (Effects)
- Smoke pH (Measures)
- Smoke pH (Measures)
- Sensory Effects—Impact (Effects)
- Kent (Lorillard)
- Kent 85 mm
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Accession nll~~;-rber 995
Lorillard h1esearch Cantar
INORGANIC ADDITIVES FOR THE'IMPROVEMENT OF TOBACCO
Submitted by: A. M. Ihrig
Report number: Date: April 7, 1977
Summary or Abstract:
Substantial increases in smoke pH and~smoke impact
can be obtained by the application of certain calcium and
potassium compounds td tobacco. These inorganic cations
or anions are naturally present in tobacco and, if addi-
tional amounts are properly applied, could be useful for
improving cigarette impact and thus, consumer satisfaction.
Mr, Winston Baznes.
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The various types of tobacco possess large variations
in th~eir content of inorganic, i.e. calcium, potassium and~
magnesium, and organic, i.e. citric and oxa;lic acids,
materials. For example, the quantity of Cal(calculated as
CaO) ranges fr=2.22 percent in flue-cured:tobacco to 8.01
percent in burley tobacco, and the quantity of citric acid
ranges from 0.78 percent in flue-cured! tobacco to 8.22
percent in burley tobacco.1 The content of these materials
in the various tobaccos depends upon many factors, such as
genetics, soil and climatic conditions, and cur}ng2 practices.
Some of these differences are shown in Table I.
The content of the inorganic substances in the leaf
directly influences the yield of ash and its alkalinity.
However, the effect of the inorganic materials on the leaf's
smoking quality is still not completely understood. Warren
Kelley3, inia series of 25 burley cigarettes, found chest
impact to be directly related to the potassium content and
inversely related to the chloride content, as shown in the
Chest Impact = 17.28 x 4.07 (nicotine) - 7.98' (chloride)l -
7.51 (acidity) - 5.20 (pH) + 4.54 (potassium:)
The introduction of low tar brands has spurred~the search
for new ways to improve the taste, flavor, and impact of these
cigarettes since many of the substances that contribute to
these factors are "filtered out". Armitage4 and Eberhart5
claim that the unprotonated or free nicotine is absorbed more
readily in the respiratory track, prod!ucingia higher level of
nicotine satisfaction.5 Thus, investigators have felt that
an increase in the smoke pH would increase the physiological
impact by affording an increased concentration of the free
nicotine in the smoke.
Experiments at Lorillard have shown that smoke pH varies
with~ tobacco types, for example: burley3, flue-cured7, and
Turkish8 cigarettes afford smoke pH values of 7.73, 5.82, and
5.11 respectively. An examination of T'able I indicates a
possible correlation between smoke pH and the concentration
of the inorganic and/or organic materials in these various
tobaccos. Thus, experiments were conducted whereby selected
inorganic and/or organic materials were added to a tobacco
blend to determine their effect on the smoke pH and thus, C)
EXPERIME'NTAL : ~
An 85 lb. sample of Kent tobacco blend without final
flavor and puffed tobacco~was obtained! from produ~ction. The
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- Z -
tobacco was weighed out into 50&gm lots, sealed in plastic
bags, and immediately placed in a 40°F cold room. With the
exception of CaOi, the additives were dissolved in 50 to 1010 ml
of water and sp°rayed on the tobaccolusing alspray cylinder to
insure a uniform application. The finely divided CaO couldbe
sprayed as a 101% aqueous slurry without clogging the sprayer.
The tobacco samples were carefully dried under the hoodand
constantly weighed in order that the moisture level, corrected
for additives, was equivalent to the original moisture level.
of the tobacco. The tobacco samples were made into 70 mm non-
filter cigarettes using the Hauni Baby. Filter sections of
20 mm length were cut off Kent 85 cigarettes and taped to these
experimental cigarettes for all smoke pH and taste evaluations.
The smoke pH analN7ses were performedin accordance to the
procedure outlined in Lorillard Research Report No. 85. Taste
Aests were conducted by various members -of-the- staff .
DISCUSSION AND RESULTS:
Table II lists the various inorganic and/or organic
materials that were added to the tobacco blend, and their
influence on the resulting smoke pH'and burn time.
The initial experiment involved the application of LiOH.
The tobacco blend was sprayed to afford a 3.01percent level
of added LiOH. The LiOH was then converted, at least in part,
to Li2CO3 by contacting the treated tobacco with gaseous carbon
dioxide in a plastic bag. Cigarettes prepared from this
LiOH/Li2CO3 treated tobacco exhibited'a good increase in smoke
pH (control = 5.55, 3% Li = 7.08) and! a modest increase in
burn time. Smoke panel stud'ies indicated a considerable
increase in smoke impact, along with a: fairly agreeable taste.
Since 1lithiumiis not normally found in tobacco, further
experiments were conducted employing potassium.hydroxide
as the additive.
Potassium hydroxide was sprayed on tobaccoito afford Q
samples containing 0.5 percent, 1.0 percent, and 2.0 percent 0
added KOH. Modest increases in smoke pH wefe observed as C.:
the concentration of the KOH was increased (control = 5.551, N
0.5% KOH = 5.84, 1% KOH = 6.34, and 2% KOH = 6.72). The ~
Smoking Panel studies indicated that cigarettes prepared ~
with the 2'o' added KOH tobacco yielded a much stronger smoke
than the control, especially for the first two or three puffs.
Towards the end of the cigarette, the sample and the control
became closer in overall taste/impact characteristics.
A series of samples were prepared from tobacco possessing
1.0, 2.0, and 4.0 percent added potassium nitrate. The data
indicated that the added KNO3 had very little effect on the
smoke pH, which would seem to indicate that the potassium ion
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itself has essentially no effect on the pH of the smoke.
Thus, the increase in the smoke pH for the KOH treated
samples could be a result of the added hydroxide anion
and not the added potassium~cation. The burn time for
the KN03 treated cigarettes decreases with increasing
KN03 concentration, indicating that the nitrate anion
was helping to promote the oxidation of the tobacco. The
Smoking Panel stated that these cigarettes possessed an
off-taste andwere not as good as the control cigarettes.
The next experiment involved the addition of CaO to
the tobacco blend. Smoking results indicated that the
addition of CaO had a greater influence on the resulting
smoke pH than thd equivalent amounts of KOH1(2o CaO = 7.43',
2% KOH = 6.72). These experiments indicated that the inorganic
additive does not have to be water soluble in order to exhibit
an influence upon the smoke pH. The burn time of these CaO
cigarettes was also greater than the corresponding cigarettes
prepared from the KOHitreated tobacco. The smoke panel studies
stated that, relative to the control, the 2% CaO cigarettes
were substantially higher in smoke impact. Generally, the
sharpness of the smoke decreased in the final.puffs.
The conversion~of potassium hydroxidle and calcium oxide
to their respective carbonates by C02 in the smoke could
account for the attenuation in the smoke impact. The carbonate
relationship needs further clarification. Possibly better
taste characteristics can be obtained! with the carbonates
..versus the more caustic potassium hydroxides and calcium
oxides. The use of carbonates may lead to an increase in
the acidity of the smoke but this relationship requires
Calcium lactate is one of the few water soluble calcium
compounds. Cigarettes prepared from calcium lactate treated'
,,...,tobacco exhibitedlincreased smoke pH (similar to CaO cigarettes)
but not increase in burn time. The smoke panel study indicated
that the taste of these cigarettes was as good as or better than
the control cigarettes.
A further experiment involved the addition of two and
four percent diammonium phosphate to the tobacco. Only a
slight increase was observed in the smoke pH (control = 5.55, G~
2% = 5.68 and 4% = 5.94), although there was an increase in,
burn time with phosphate addition. ~
Apparently the smoke impact from Maryland tobaccos is ~
equivalent to that from burley tobaccos, even though the L~
latter contains a: higher concentration of nicotine and total
volatile bases.9 However, Maryland tobaccos are high in
sulfur compounds as compared to burley or flue-cured tobaccos.
Thus, a set of sample were prepared containing 1.55 percent
and 3.10 percent added potassium sulfate to determine whether
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the smoke impact couldbe increased through sulfate anion
addition. The added K2CO4 decreased the smoke pH slightly
(control = 5.33, 1.55o K2S'O4 = 5.48, and 3.101 K2SO4 = 5.47).
There was no detectable increase in smoke impact for the
sulfate treated cigarettes. Surprisingly, the taste was
not adversely affected! under these conditions. The burn
time was increased, indicating that either sulfate or phosphate
addition might be potentially useful for extending burn time.
The addition of sulfate in the presence of applied alkaline
compounds requires further clarification.
In~a quick experiment, cigarettes containing 2.0 percent
KOH additive were injected with 50 ul of an aqueous solution
containing 4.5 ntg of K2S'O4. The solution was injected in the
first 10 mm of the tobacco end. The sulfate treated!cigarettes
seem to have more impact than the control cigarette which
contains 2.0 percent KOH.
The last set of samples were prepared to determine what
effects, if any, took place when citrate of malate anions
were added in~combination with certain of the before-mentioned
inorganic materials (notably CaO). For the four samples listed
in Table II, in no case did the resulting smoke pH equal or
exceed the smoke pH of the corresponding CaO treated samples.
Thus, the addition of the org~-~.nic anions only seems to moderate
the affects of the added CaO~ material.
Mr. Terry Jessup requested that the writer help him find
a method to increase the initial smoke impact for an experi-
mental 2.0 mg, tar cigarette using aniair diluted filtration
system and~porous cigarette paper. It was proposed that 2.0
percent C'aOland 2.0 percent potassium citrate be added to this
low tar blend. The additives were applied to a 50 pound~
sample of tobacco which was made into cigarettes inithe pilot
plant. These cigarettes exhibited a substantial increase in
impact but possessed an off-taste, according to the expert
The overall series of experiments demonstrates that the
addition of calcium oxide, potassium hydroxide and calcium
lactate increases tli~e smoke pH and hence thie,delivery of
unprotonatedinicotine. Unfortunately, the inorganic additives
generate taste problems which could possibly be overcome by a
judicious application of the properbas,ic compounds without
sacrificing smoke impact. These experiments indicate that the
overall basicity of the additive influences smoke pH and impact
more than the presentce of a given cation, as exemplified by
the pH differences in the potassium hydroxic3e and potassium CD
nitrate samples. Calcium and potassium salts occur naturally Lj
in tobacco, thus extensive toxicity studies shouldinot be OD
necessary before these materials could be incorporated into 0
cigarettes. / V,
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Table Z. Representative Analysis of Cigarette Tobaccasl
Component Percen.t_ Flue-Cured
Type 13 Burley
Type 31 Maryland
Type 3 2 Turkish
Ca as CaO 2.22 8.01 4.79 4.22
K as K20 2.47 5.22 4.46 2.33
Mg as MgO 0.36 1.29 1.03 0.69
Cl 0.84 0.71 0.26 0.69
Phosphorous as P205 0.51 0.57 0.53 0.47
Sulfur as S04- 1.23 1.98 3.34 1.40
Alkalinity of H20
solubles as ml 1N 15.9 36.2 36.9 2.25
Malic Acid 2.83 6.75 2.43 3.87
CitricAcid 0.78 8.22 2.98 1.03
Oxalic Acid 0.81 3.04 2.79 3.16
Nitrate Trace 1.70, 0.08 Trace
NH3 0.0119 0.159 0.130 0.105
Ash 10'.81 24.53 21.98 14.78
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Table II: The Influence of Inorg,anic and/or Organic Additives
on Smoke pH and Number of Puffs
of Samples Smoke pH Number of
Strongly Al kaline Additives:
Control 5.55 8.9
0~.5% KOH 5.84 9.3
1.0% KOH 6.34 9.6
2.0% KOH _ 6.72 9.6
3.0% LiO H/Li2CO3 7.08 9.8
1.0% KNO itives:
2.0% KNO 3 5.68 7.9
4.0% KNO 3 5.70 7.4
Water insol uble alkaline additives:
1.0% CaO : 6.74 10.6
2.0% CaO 7.43 10.4
4.0% CaO 7.49 9.6
Soluble Cal cium Salt:
Control 5.60 8.5
1.09% Ca lcium lactate 658 85'
Ammoniurn ph osphate additives :
2.0°% (.1H 4) 2HPOA 5.68 9.8 '
4.0% (NH 4) 2HP04 5.94 10.8'
Sulfate Add itives:
Control 5.53 6.6
1.55o K2 SO4 5.48 8.6
3.10% K2 SO4 5.47 9.0
Mixture of Additives:
Control 5.53 6.6
2.0% CaO :, 2% potassiumicitrate 6.90 8.5
1.0% CaO , 1°s' potassiumicitrate 6.44 8'.0
1.0% KOH , 2'% potassiumicitrate,
, 01.5% K2SO4 6.83
0.25% K2 , 2.0% potassium citrate,
ic acid, 2.0% KOH,
S04 and 2.0% (NH4)2HPO4 7.13
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1. "Tobacco" in ECT lst ed., Vol. 14, pp. 242-261,
2. W. R. Harlen and J. M. Moseley, The American Tobacco
W,. G.'Frankenburg,andi A. M. Gottscho, Ind. Eng. Chem.
3. Warren Kelly, Lorillard Research Center Report 528.
4. A. K. Armitage and D~. M. Turner, Nature, 226, 1231 (1970).
5. R. Eberhart and H. Schievelbein, J. Nat. Cancer Inst., 48
6. G. P. Morie, Tobi. Sci., 16, 167 (1972).
7. Warren Kelly, Lorillard Research Center Report 538.
8!. Research Notebook of A. M. Ihrig.
9. Private Communication - Terry Jessup.
10. Erston V. Miller, The Chemistry of Plants, Reinhold
Publishing Corp., New York, 1957 p.16.
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