October 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
were usually located a t a depth of 1 or 2 inches below the surface of the liquid. While raising the temperature of the solution (slowly, to avoid turbulence owing to the evolution of chlorine), a momenta ry spark wm discharged periodically. In these tests there was no evidence a t any time of propagation of reaction through the liquid phase itself. However, a t liquid temperatures in the range from 18" to 37" C., a small, burning bubble of gas formed around the spark and rose to the surface, expmding as it rose. Its evolution from the liquid was accompanied by a brief flash of orange-red flame and a puff of dense smoke due to momentary ignition of the vapor above the liquid. Increasing the input to the spark coil to 8 volts widened the ignition limits to 13.5" and 39" C., but further increase to 10 to 12 volts had no more effect. At these limits, the calculated solubilities are, respectively, 0.37 and 0.135 mole of chlorine per mole of benzene. These temperatures are not precise, duplicate determinations usually showing variations from 0' to 4" C. This may well have been due to changes in composition resulting from a certain amount of photochemical chlorination induced by the spark or by light entering the open top of the tube during the course of a determination. When a similar ignition was carried out in a 33-mm. tube 44 inches long, which was three quarters filled with solution at 22' C. and had the spark located 28 inches below the surface, the expansion of the rising gas bubble was sufficient to eject one third of the liquid from the tube.
2343
SAFETY HAZARD
The data reported here indicate that benzene-chlorine mixtures are in general less hazardous than benzene-air mixtures. In metal equipment, at atmospheric pressure, ordinary safety devices should be adequate. Even at atmospheric pressure, however, the vapor phase above liquid benzene in an atmosphere of chlorine is potentially hazardous a t temperatures above the flash point of 13" to 14" C., up to at least 60" C. Liquid solutions of chlorine in benzene a t atmospheric pressure and at temperatures down to a t least 10" C. and perhaps lower, contain insufficient chlorine to be explosive and are not ignited by inflammation of the contiguous vapor phase. Even so, the occurrence of a spark (or, presumably, any other sufficient source of heat) in a volume of the liquid solution may result in an evolution and inflammation of vapor beneath the surface. This, on a large scale, might present a considerable hazard. LITERATURE CITED (1) Brooks, B . T., IND.ENO.CEEM.,17,752(1925). (2) Hass, H. B., "Science of P e t r o l e u m , " p. 2788, L o n d o n , Oxford University Press, 1939. (3) McBee, E. T.,Hass, H. B., a n d Pierson, E a r l , IND.ENG.CHEM., 33,181(1941). (4) U. S, D e p t . I n t e r i o r , Bur. Mines, Bull. 279 (1939).
RECEIVED January 29, 1951
Burley Tobacco J
RELATION OF THE NITROGENOUS FRACTIONS TO SMOKING QUALITY J. M. MOSELEY, W. R. H A R M , AND H. R. HANMER The American Tobacco Co., Richmond, Va. Efforts to evaluate, by chemical means, and to improve the quality of Burley tobacco have engrossed the attention of many research workers in the United States Department of Agriculture and state experiment stations. The authors' laboratory has been engaged in this fieldof research for many years. There is a striking paucity of published information on the subject. These findings provide one means of correlating composition with recognized standards of quality. This paper reports a useful method of evaluation which has not heretofore been published and which is being employed as a guide in the development of new and improved varieties of Burley tobacco. Burley tobacco occupies about 450,000 acres of fertile farm land and provides a cash income of approximately $250,000,000 annually to over 275,000 individual farmers. A contribution to the evaluation, hence improvement, of this economically important crop is significant.
T
H E various qualities by which the leaf expert judges tobacco include color, body, conformation, texture, elasticity, and aroma. The second of these, body, is the most difficult to define. Theterm as used in the trade appliesin general tostrengthof smoke and is intimately related to smoking quality. Body is recognized principally by the thickness, texture, and gumminess of the leaf, but the exactness with which the chemical characteristics of leaf are related to the physical is subject to variance. The leaf experts, making use of knowledge acquired from long experience, maintain a remarkable degree of proficiency in the judgment of quality of leaf in terms of manufacturing characteristics, burning
properties, and certain attributes of taste such as sweetness and aroma. The criteria of quality which they employ are not so accurately indicative of strength and blending properties. A crop grown under abnormal conditions may possess unusual smoking characteristics not easily recognized from the physical properties of the leaf. This, with the expanded nature of the industry, lends increasing importance to chemical methods for both evaluation and maintenance of uniform quality. Various investigators have attempted to correlate analytical data with,the observed quality of flue-cured and foreign types (9, 21, 2.2, 16,27, 18). In general, carbohydrates, essential oils, and resins are prominently classed among the compounds which are positive in their influence on tobacco quality. Proteins, pectins, oxalic acid, and ash are among the substances generally considered to have a negative influence. Burley tobacco, the most important of the air-cured types, is widely used in blended cigarettes, pipe mixtureg, and plug chewing products. The cutter grades such as shown in Figure I furnish the bulk of the cigarette leaf. I n popular brands of domestic cigarettes it is usually blended with flue-cured, Turkish, and Maryland. Quality of cigarette grades of Burley is therefore considered only from the standpoint of the combined effect when blended with types of dissimilar composition. I n this respect, the problems of American investigators differ from those in foreign countries, where the art of blending of types has not been developed. Detailed work on Burley tobacco has been reported by Shedd (19, bo), who determined total nitrogen, nicotine, nitrate nitrogen, and some ash constituents on good, medium, and common samples. His data showed a higher potash content for the better
INDUSTRIAL AND ENGINEERING CHEMISTRY
2344
TABLE I.
ANALYSIS O F FARhIERS'
-~
Total leaf %-eight, % T o t a l nitrogen, % Piicotine, Yo Ammonia, % Asparagine amide nitrogen, % Glutamine amide nitrogen, % Protein nitrogen, 70 Peptide nitrogen, % a-Amino nitrogen, % S i t r a t e nitrogen, % Total ash, 70, Potassium oxide, % Calcium oxide, % Magnesium oxide, % Chloride, % Crude fiber, 70 Ether extrwt, % PH
l'lyings 9.49 3,w 2.42 0,092 0,090 0 052 1.97 0.137 0.198 0.357 23.98 3.85 7.60 1.19 0.25 9.66 6.84 6.20
Trash 14.48 4.26 3.04 0.126 0.132 0.053 2.03 0.152 0.285 0.299 21.69 4.04 6.59 1.21 0.27 9.59 8.05 6.00
Louisville Distriot Bright Lugs leaf 16.06 28.96 4.37 4.77 3.82 3.51 0 177 0.138 0,303 0.154 0,067 0.06j 1.94 1.79 0.102 0.072 0.345 0.599 0.213 0.284 21.48 20.56 3.78 3.89 6.74 6.33 1.18 1.09 0.17 0.17 9.23 8.74 7.86 8.19 5.62 5.86
Vol. 43, No. 10
GRADES,BURLEYTOBACCO, 1939 CROP Red leaf 22.79 6.67 4.12 0.259 0.492 0.082 2.03 0.119 0.721 0 141 18 25 3 40 5.59 1 03 0 17 8 65 8.05 5.62
grades while the proportion of the anions, including uitrate, chloride, and sulfate, did not show any trend among the grades. This indicates that the quantity of potassium in organic combinat,ion is greater in the better grades and is in accord with the observat,ions of Schlosing ( 1 6 ) and Garner ( I O ) , who noted t,he beneficial effect of potassium in combination ivit,li the organic acids on the burning quality. As Burley t,obacco, on combustion, yields smoke which is usually higher in volatile bases than that of other cigarette t,ypoa (8), much interest attaches to the niti~ogenousmaterials which, subject t o the conditions of smoking, give rke to volatile bascs.
Tips 8.22 5.64 3.55 0.262 0.447 0.077 2.16 0.143 0.747 0.128 16.78 3.45 4.55 0.90 0.21 10,oo 6 86 5,62
Flyings 11.07 3.73 2.02 0.077 0.116 0,040 1.97 0.125 0.232 0.242 23.58 4.13 7.41 0.90 0.06 9.95 8.00 6.22
Trash 22.52 3.66 2.78 0,082 0.118 0.054 1.74 0.144 0.286 0,130 22,29 4.22 6.75 0.82 0.06 9.65 8.74 6.03
hIaysville Distriot Bright Lugs leaf 27.05 18.68 3.81 4.48 2.81 3.89 0.127 0.177 0.119 0.361 0.054 0.062 1.74 1.62 0,148 0.141 0,293 0.570 0.167 0.126 21.88 20.18 4.15 3.96 7.05 6.3B 0.81 0.76 0.09 0.09 9.72 9.24 8.67 9.13 6.01 5.71
Red leaf 9.38 4.88 3.79 0.206 0.406 0.058 1.75 0.140 0.745 0.075 18.44 3.65 5.53 0.77 0.08 9.03 8.07 5.69
Tips 11.30 4.86 2.67 0,236 0.388 0.067 1.99 0.124 0.716 0.040 17.58 3.74 4.97 0.83
0.13 10.39 7.44 5.69
These, with Lexington, 0%-ensboro,and Eastern Tennessce, are the major subdivisions of the belt. The samples represented here were collected from farmers' barns during the first week in October. The sampling was done by experienced leaf experts who took the precautions necessary to obtain an accurat,e cross Rectiori of the tobacco grown in these districts. Freshly cured plants were selected from a large number of barns scattered throughout the grov-ing districts. The individual plants were assembled and graded according t o the customary pract,ice. After removal of the midribs, the samples were air-dried, milled, and stored in tightly closed jars until analyzed. A l l results are reported on a MANUFACTURERS' CLASSIFICATION
FARMERS' GRADES
TIPS
RED L E A F
RED LEAF:
BRIGHT L E A F
CUTTERS
A
io
GRANULATORS
r
Figure 1. Burlel Plant Showing Farmers' Grades and RIanufactnrers' Classification
The total nitrogen content has flequently been found to correlate with strength of tobacco. This, when broken down into its individual components and examined in conjunction with the mineral constituents, furnishes a guide to smoking and blendirlg characteristics. Table I gives the analysis of farmers' grades of the 1939 crop of Burleg tobacco from the Louisville and Maysville districts.
moisture-free basis, The nitrogenous groups other than nicotine are calculated as ammonia. Moisture is determined as the loss in weight upon drying for 3 hours in a forced-draft oven at 99 O to 100" c. Total nitrogen is determined by thp Kjeldahl-Gunning- Arnold n1pthod ( 1 ) as modified to include the nitrogen of nitrates. Nicotine is steam distilled from an alkaline suspension of the
INDUSTRIAL AND ENGINEERING CHEMISTRY
October 1951
sample and precipitated as recommended by the Association of OfficialAgricultural Chemists ( 3 ) . Ammonia is determined spectrometrically according to the technique of Pucher (14). Glutamine is determined as the increase in ammonia nitrogen after hydrolysis a t pH 7 for 2 hours in a boiling water bath, according to the procedure of Vickery (81). Asparagine is determined as the difference between the glutamine and the total amide nitrogen determined after hydrolysis with 6 N sulfuric acid, according to the method of Pucher (14).
:r r
I 0
N
/ A M I N O LOUIS VILL E 1939 CROP
/Q..
3 ' 4 70
240
-
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eo r roM
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I 1
70
MAYSVILL E 19.39 CROP
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7
2.40-
ur y.30h
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-
-
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TOTAL AMIDO h
-.w-
P
*
eorrom IO
20
TOP
80
40
so
60
70
ao
90
Amino nitrogen is determined in the Van Slyke manometric apparatus according to the direction of Peters and Van Slyke ( I S ) on a solution prepared according to Vickery ( 2 1 ) . Peptide nitrogen is determined as the increase in amino nitrogen upon boiling for 6 hours with 12 N sulfuric acid (81). Protein nitrogen is determined by the Kjeldahl-Gunning-Arnold method ( 1 ) on the insoluble fraction obtained after boiling for 5 minutes with 0.5% acetic acid. Nitrate nitrogen is determined as the volatile alkalinity obtained by steam distillation from a dilute alkaline solution with the addition of Devarda's alloy after first removing the bulk of volatile bases by distillation from strong alkali. A blank is conducted on a duplicate sample redistilled from dilute alkali without the addition of alloy. Ash is determined by heating the samples at 450' to 500" C. in a muffle to constant weight. Potassium is determined by the procedure recommended by the AOAC for organic compounds ( 2 ) . Calcium, magnesium, and chlorine are determined by the official methods of the AOAC as recommended for plants (4-6). Crude fiber is determined by the AOAC method for grain and stock feeds (7). Ether extract is determined by extracting a 2-gram sample for 24 hours in a Soxhlet extraction apparatus. The ether is evaporated on a water bath at 35" to 40" C. and the residue dried to constant weight under reduced pressure. p H is determined with a glass electrode on an aqueous solution prepared by infusing a 2-gram sample for 1 hour in 100 ml. of water. These data show typical relationships between the analyses of the individual grades. Total nitrogen is observed to increase fairly regularly over the entire stalk range. Nicotine is higher in the upper portions of the stalk, reaching a maximum in the leafy grades and declining in the immature tips. The ammonia con-
2345
tent increases gradually with succeeding stalk positions (Figure 2). Asparagine exhibits a sharp increase in the region of transition between lugs and leaf and diminishes slightly in the tips. Glutamine is slightly higher in the upper portion of the plant. Amino nitrogen parallels and is roughly twice as great as the asparagine amide nitrogen. The grades vary widely in their content of the soluble nitrogenous compounds-nicotine, ammonia, and amides. This group of substances is largely responsible for the volatile bases of smoke. A comparison of the analyses of the samples from the two districts, Maysville and Louisville, shows that the nitrogenous groups are lower in the Maysville samples and differ in their trend with respect to stalk position. The nicotine content of the leaf from the Louisville district is more constant than that from the Maysville, and reaches a maximum higher up on the plant. The difference in characteristics of the leaf from the two districts becomes more significant when it is considered that they are not widely separated geographically. The difference shown here between the two districts applies only to the 1939 crop and may be revereed in other seasons. DETERMINATION OF VOLATILE BASES
In this laboratory a method has been developed for the determination of the volatile,bases of tobacco which has been extremely useful in the characterization of Burley tobaccos from the standpoint of strength, smoking quality, and adaptability to blending with other types. An alkaline suspension of tobacco is steam distilled under controlled conditions. The volatile material thus removed is collected in an excess of standard acid which is subsequently backtitrated with standard alkali. The neutralized distillate is reserved for the gravimetric determination of nicotine. Nornicotine normally comprises about 10% of the total alkaloids ot Burley tobacco. About 60% of the nornicotine is distilled over and determined as nicotine by this procedure.
Figure 3. Distillation Assembly for Determination of Volatile Bases
The conditions of the distillation are designed to ensure the complete removal of nicotine and ammonia from the sample and that portion of the hydrolyzable nitrogen compounds which is most effective in determining the character of the smoke. This last condition is based on the results of numerous smoking tests designed to ascertain the range of greatest practical significance. The total volatile bases (T.V.B.) obtained by this procedure have been found to parallel the strength of the sample and are intimately related to the term body as used in the trade. The resultant data can be interpreted in terms of base distribution as well as total base content. The value for nicotine is necessary for the estimation of the physiological strength of a sample, but of further importance is the calculated ratio of nico-
INDUSTRIAL AND ENGINEERING CHEMISTRY
2346
tine to total volatile bases. This ratio reflects the influence of such factors as stalk position, ripeness, fertilization, and growing conditions, and is an index to palatability of smoke, The calculated values for volatile bases other than nicotine (total volatile bases minus nicotine) include all of the true ammonia, the more easily hydrolyzable amide compounds, and a fairly constant amount of ammonia derived from the insoluble proteins. This value is more readily interpretable in terms of smoking quality than a compilation of the individual nitrogen groups, such as that shown in Table I. The value for total volatile bases in conjunction with nicotine yields information comparable to a much more evhaustive analysis.
A 5-gram sample of tobacco is weighed and transPROCEDURE. ferred to an 800-ml. Kjeldahl flask. Seventy-five milliliters of standard trisodium phosphate solution ( 8 ) are added and the flask is connected to an apparatus arranged for distillation in a current of steam. The distillate is collected in a 1000-ml. Erlenmeyer flask rontaining an excess of 0.1 h7 hydrochloric acid, A burner beneath the reaction flask is turned on and adjusted to a
$01
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PROTEIN N
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IO PO 30 40 50 6o 70 ao FLYINGS TRASH LUGS BRIGHT LEAF REO LEAF STALK POSI TION- WEIGHT BASIS
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309:
l
distillation. The excess of hydrochloric acid is titrated with 0.1
N sodium hydroxide using 7 to 8 drops of methyl red-methylene
blue, a n achromatic indicator. The ammonia equivalent of the hydrochloric acid used is calculated as per cent of the sample on a moisture-free basis and reported as total volatile bases. The neutralized distillate is made up to a volume of 1000 ml. and the nicotine in an appropriate aliquot, usually 250 mi., is determined by the AOAC procedure ( 3 ) . The per cent nicotine is multiplied by 0.105 to obtain the ammonia equivalent. This is subtracted from the per cent total volatile bases to obtain the value total volatile bases minus nicotine. The ammonia equivalent of the nicotine is divided by the per cent total volatile bases to obtain the ratio of nicotine to total volatile bases, Appreciable variations in the pH or volume of the reacting mixture, or rate of distillation will impair the preci4on of the method. With practice, an operator can reproduce duplicate analyses consistently within =t0.005% total volatile bases. Employing a 12-burner assembly, such as that shown in Figure 3 , 96 samples can be distilled in one day. The per cent total volatile bases ranges from 12 to 25% of the total nitrogen. It includes, in proportion to their ease of hydrolysis, all of the important nitrogenous groups, except nitrates and a-amino acids. The importance of these two forma is hardly sufficient to justify their separate determination in control work. A large quantity of amino nitrogen undoubtedly affects the smoking quality adversely, but this has been shown to parallel the amido group and may be estimated from the value for volatile bases other than nicotine and free ammonia. Analyses by this method of some nitrogen compounds which occur widely in plant tissues appear in Table 11.
90
TIPS
TABLE 11. AKALYSIS OF PURESUBSTANCES Total Nitrogen, .?.V.B. x loo
MAYS VILLE I 9 3 9 CROP
----
--
-.---.--.--.--
PROTEN N
$LO1
T OP
,
~
% as NIia
Total Nitrogen
31.80 25,43 23,63
99.2 99.8 99.2
Glutamine -4sparagine
22.28 22.54
46.3 33.0
Glycine Glutamic acid Aspartic acid
22.46 11.45 12.57
Edestin Vegetable albumin Peatone
19.93 13.83 17.77
Substance Ammonium chloride Ammonium sulfate Ammonium oxalate
T VBX5
,
o.--_o--c--L-
EOTIOM
Vol. 43, No. 10
~
0.24 0.02 0.02 13.0 17.3 3.1
Tobacco protein from farmers’ grades of the 1939 crop has been hydrolyzed by this procedure. The volatile alkalinity calculated as ammonia varied from 4.991; of the total protein nitrogen in the tips to 5.570 in the flyings. OF BIJRLEY Tosacco BY CROP,DISTRICT, AND GRADE TABLE111. ANALYSIS 1938
Flying?
Trash
Lugs
Bright leaf
Red leaf
___ Tips
1939 ____._____
Flyings
_______
Trash
Lugs
Bright leaf
Red leaf
0.575 2.78 0.283 0.51 22.29
0.632 2.81 0.337 0.47 21 88
0.887 3.89 0.479 0.46 20.18
0.874 3.79 0.476 0.46 18 44
0.843 2.67 0.563 0.33 17.58
0.671 3.04 0.352 0.48 21.69
0.741
0.904 3.82 0.503 0.44 20.56
1.113 4.12 0.679 0.39 18.25
1.024 3.55 0.651 0.36 16.78
Tips
OWEXEEORO
MAYEYILLE T V.A. yo Nicotide, % T.V.B.-nicotine, % Kicotine/T.V.B. ratio Ash, %
0.4iO 1.64 0.298 0.37 25.70
0.588 2.43 0,333 0.43 23.76
0,743 2.83 0,446 0.40 21.59
0,980 3.33 0,630 0.36 21.88
1.167 3.48 0,802 0.31 19.92
1.122 2.68 0,841 0.25 19.41
T.V.B., % Kicotine, % T.V.B.-nicotine, % ’ Nicotine/T.V.B. ratio Ash, %
0.543 2.24
0.498 2.14 0,273 0.45 24.71
0.688 3.02 0.371 0.46 22.45
0.728 3.13 0.399 0.45 21.97
0.912 3.17 0.579 0.37 20.48
0.935 2.89 0.632 0.32 19.40
0,452 2.02 0,240 0.47 23.58
LOUIfiVILLE
0.308 0.43 22.51
0.547 2.42 0.293 0.46 23.98
3.51 0.365 0.51 21.48
October 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
The graphs shown in Figure 4 demonstrate the relation of total volatile bases to the total and protein nitrogen. The total volatile base curve, while showing a general similarity to that of the total nitrogen, ia much more sensitive than the latter since its components are predominantly the water-soluble forms. I n contrast to the curve for total amido nitrogen shown in Figure 2, it does not rise so steeply in the cutter grades, since the portion of total volatile bases contributed by ammonia and the relatively constant protein fraction have a stabilizing effect. Good quality of Burley tobacco is related, in general, to a low content of total volatile bases, a high ratio of nicotine to total volatile bases, and a reasonably high mineral content. For total volatile bases it is necessary to set a mjnimum value as well as a maximum. Extremely low bases indicate overripeness, chaffiness, and a general lack of character. Aside from the deficiency of aroma in such tobaccos, they sometimes carry an unpleasant, earthy taste. While the data for total volatile bases are of value primarily as a measure of strength, the ratio of nicotine to total volatile bases bears a very consistent relationship to the quality of the smoke. This term incorporates such factors as smoothness and palatability as opposed to irritation and bitterness (8). The heavier bodied grades frequently possess better aromatic properties than the light. These may be very desirable for blending with milder grades if the nicotine bears the proper relation to the other volatile bases. COMMERCIAL APPLICATION
The practical application of the data obtained by analysis for total volatile bases is demonstrated by Table 111, which shows data for successiveyears from three growing districts. These samples, like those presented in Table I, were collected from individual farmers’ barns a t the completion of curing. The Owensboro leaf of the 1938 crop was considerably milder than that of 1939, as shown by the lower content of total volatile bases and nicotine over the entire range of farmers’ grades. That it was less mature is indicated by the lower ratio of nicotine to total volatile bases. The 1939 Maysville tobacco was typical of a very mild and well-matured crop. Leaf of cigarette quality extended from the trash through the red leaf. The 1938 Maysville crop was stronger than that of 1939, although throughout the remainder of the Burley area, the 1939 crop was substantially the stronger of thetwo. The 1939 growing season, because of highly localized rainfall and and other factors, produced Burley leaf of more widely differing characteristics between the various districts than is usual. The data on the Louisville crops of 1938 and 1939 indicate that the latter had slightly greater strength, as shown by its higher total volatile base content. The volatile base distribution in each was good, but the 1939 crop contained less leaf of cigarette quality. I n 1938 the three districts did not show any consistent difference with respect to strength for the individual grades up through the Bright leaf. The red leaf and tips showed least strength in the Owensboro district, intermediate in Lousiville, and greatest in Maysville. This order is reversed for the three districts in 1939. Over a period of several years, the average strength of the leaf grown in the five districts will be approximately the same. For a particular growing season, however, the quality of leaf which is offered in a given area can be judged only with great difficulty without the benefit of data obtained from chemical analyses. Table I V shows the analyses of tobacco from three markets in the Eastern Tennessee District for 1949, a year of abundant rainfall in the early part of the growing season. Knoxville had very light bodied tobacco all the way up the stalk and the flyings and trashes were overly thin. Asheville had low nicotine but total volatile base minus nicotine was excessive in the upper stalk positions, The nicotine content of the Abingdon tobacco exceeded that of the other two and was higher than desirable in the leafy grades. This market had a favorable ratio of nicotine to total volatile bases. It is, of course, impractical to set up a standard to which all leaf
2347
TABLEIV. ANALYSISOF BURLEYTOBACCO BY MARKETAND GRADE,1949 Flyings T.V.B % Nicotige % T.V.B.-diootine,
%
Nicotjne/T.V.B. ratio
Ash, %
T.V.B % Niootile % T.V.B.-dicotine,
%
Nicotine/T.V. B. ratio Ash, %
T.V.B % Nicotige %
T.V.B.-dicotine,
%
Nicotine/T.V.B. ratio Ash, %
Trash
0,347 1.40 0.200 0.42 27.59
Lugs
Bright Leaf
Red Leaf
Tips
KNOXVILLE 0,354 0.617 1.27 2.94
0.820 3.91
0.582 2.86
0.638 2.69
0,221
0.409
0.282
0.356
0.38 24.46
0,308 0.50 22.03
0.50 21.66
0.52 22.67
0.395 1.56
ASHEVILLE 0.358 0.481 1.59 2.31
0.657 3.32
0.925 3.78
0.231
0.191
0.308
0.528
0.42 26.65
0.47 23.80
0 238
0.51 22.63
0.550 2.47
ABINQDON 0.513 0.558 2.46 2.84
0.291
0.255
0.47 25.10
0.50 24.77
0.53 21.30
0.260 0.53 22.87
0.43 19.19
0.824 4.24
0.908 4.49
0.379
0.437
0.54 21.83
0.52 21.04
0.44 18.68 0.788 1.76 0.603 0.23 19.22 0.830 3.51 0.461 0.44 20.68
can be made to conform. Bradford (8) has described the blending of several dissimilar types to form a finished cigarette. Similarly, by the blending of many grades within a type, it is possible to equalize the variations among individual grades. This is accomplished by thorough and repeated mixing operations and the various processes to which the tobacco may be subjected in the course of manufacturing. The manufacturers’ stock should be segregated according to crop, district, and grade. By systematic analysis over a period of years it is possible to establish standards for each grade, to control the blends, and to maintain a high degree of uniformity in the finished Droduct. LITERATURE CITED (1) Assoc. Official Agr. Chemists, “Official and Tentative Methods of Analysis,” 4th ed., p. 25, Washington, D. C., 1935. (2) Zbid., p. 30. (3) Zbid., p. 60. (4) Ibid., p. 123. (5) Ibid., p. 124. (6) Ibid., p. 131. (7) Zbid., p. 340. (8) Bradford, J. A., Harlow, E. S., Harlan, W. R., and Hanmer, H. R., IND.ENQ.CHEM.,29, 45-50 (1937). (9) Darkis, F. R., Dixon, L. F., Wolf, F. A., and Gross, P. M., Zbid., 28, 1214-23 (1936). (10) Garner, W. W., U. S. Dept. Agr., Bur. Plant Ind., Bull. 105 (1907). (11) Gartner, K., Magyar C h m . Foly6ira4 45, 19-30 (1939). (12) Hall, N. F. B., and Earl, J. C., J. Council Sci. I n d . Research, 8, 277-80 (1935). (13) Peters, J. P., and Van Slyke, D. D., “Quantitative Clinical Chemistry,” Vol. 2, p. 385, Baltimore, Williams & Wilkins Co., 1932. (14) Pucher, G . W., Vickery, H. B., and Leavenworth, C. S., IND. ENG.CHEM.,ANAL.ED., 7, 152-6 (1935). (15) Pyriki, C.,2. Lebensm. Untersuch. u. Forsch., 88, 404-7 (1948). (16) Schlosing, T., L a n d w . Vers. Stu., 3, 98 (1860). (17) Schmuck, A,, Central Institute for Tobacco Investigations (U.S.S.R.), Bull. 33 (1927). (18) Schmuck, A., State Inst. Tobacco Invest. (U.S.S.R.), Bull. 20 (1 924). (19) Shedd, 0. M., Kentucky Agr. Expt. Sta., Bull. 258 (1925). (20) Ibid., 308 (1930). (21) Vickery, H. B., Pucher, G. W., Leavenworth, C. S., and Wakeman, A. J., Conneaticut Agr. Expt. Sta., Bull. 374 (1935). RECEIVED December 18, 1950.
