- Détails du magazine
- Première publication
- 01 Jan 1992
- Période de publication
- 4 fois par an
- Accès libre
Pages: 63 - 66
Fraction I protein is the most abundant protein in tobacco and accounts for 50 % of its soluble protein. It is composed entirely of amino acids. Its specific nutritional value is comparable with milk and surpasses that of soybeans. During tobacco combustion, Fraction I protein may contribute to the formation of HCN and other undesirable nitrogenous constituents in smoke. It can be removed from harvested leaf tobacco through homogenized leaf curing (HLC) process to improve leaf quality and usability. Considering the total world tobacco production as a whole, Fraction I protein and other soluble proteins so recovered may provide enough food for millions of people. In addition, there will also be a better smoking product
- Accès libre
Cigarette Smoke Formation Studies: IV. The Dynamic Measurement of the AxiaI Density of a Burning Cigarette
Pages: 67 - 71
Much research has gone into establishing the temperature gradients that exist inside a burning cigarette. These temperature gradients should correspond to changes in the density of the tobacco column due to the condensation and subsequent re-evaporation of volatiles resulting from pyrolysis, combustion, and final ash formation. These dynamic measurements on the burning cigarette were made using a modified beta thickness gauge. A beam of collimated beta particles from a 32P-source is projected through the side of a cigarette at a fixed position. The cigarette is allowed to burn past the focused beta beam. The number of transmitted particles is dependent upon the density of the mass penetrated by the incident particles, and is reflected as a change in the number of counts detected per unit time. A density profile of the burning cigarette has been established for both the puffing and static modes. These density changes are correlated with published temperature profiles. The buildup of the volatile materials (mostly water) on the tobacco rod behind the pyrolytic region is presented. The rate of evaporative losses of these condensables is shown to be dependent on puff count (cigarette length). A detailed density profile of the condensing materials from a single puff has been established. The relationships of these density changes to current smoke formation theories are discussed
- Accès libre
Pages: 72 - 78
If the distribution of specific smoke components with respect to particle size were significantly different than the size distribution of particulate matter, a compound or group of compounds might be selectively removed by the selective filtration of a given particle size. Various techniques have been used to determine the particle size distribution of a few smoke components. Berner and Marek used a Goetz aerosol spectrometer to determine the size distribution of potassium in smoke; and Owen, Westcott and Woodman used a conifuge to examine the distribution of three smoke components. In the present work, a cascade impactor was used to separate smoke particles into four fractions of 0.25 to 1.0 µ in diameter based on the principle that particles in a moving airstream impact on a slide placed in their path, if their momentum is sufficient to overcome the drag exerted by the airstream. The particle size distribution of five organic compounds: indole, nicotine, diethyl phthalate, norphytene, and neophytadiene were determined. These size distributions were compared to the distribution of total particulate matter (TPM) and the following observations were made:
1. All compounds were distributed in a pattern similar to that of TPM. Therefore, the selective filtration of a given compound by selective filtration of a given particle size is probably unfeasible.
2. The concentrations of indole and nicotine were higher in the medium-size particles (0.5 to 0.75 µ) than in the small or large particles.
3. It is known that cellulose acetate filters are more efficient for the filtration of small and large particles than they are for medium-size particles. Therefore, the high concentration of nicotine in the medium-size particles may contribute to the slightly higher filtration efficiency these filters have for the TPM than they have for nicotine.
- Accès libre
The ldentification of High Molecular Weight Polynuclear Aromatic Hydrocarbons in a Biologically Active Fraction of Cigarette Smoke Condensate
Pages: 79 - 101
A gel filtration chromatography method was developed for the isolation and concentration of the high molecular weight polynuclear aromatic hydrocarbons (PAH) contained in the most biologically active fraction of cigarette smoke condensate (CSC). The unusually complex mixture of large PAH found in CSC necessitated the use of preparative gas chromatography followed by high-pressure liquid chromatography to achieve separation and identification. Mass spectral, ultra-violet absorption, and chromatographic retention data were needed for the comprehensive identification of the large molecular weight PAH components of CSC. The majority of the more than 200 isolated compounds were identified. Compounds newly identified in CSC included 3,4-dimethylenepyrene, 3,4-trimethylenepyrene, cyclopenta(c,-d)pyrene, 4,5-methylenetriphenylene, benzo[b]perylene, and several dibenzofluoranthenes.
- Accès libre
Pages: 102 - 106
A vast storehouse of genetic variability is contained in collections of Nicotiana tabacum and Nicotiana species. Methods and techniques of using this material to alter chemical constituents of commercial tobacco are discussed. Simple Mendelian procedures that have resulted in improved varieties may also be used to change chemical constituents. Male-sterility permits the rapid production of F1 hybrids in special situations. Interspecific hybridization allows the transfer of new germplasm. The haploid/diploid method offers instantaneous homozygosity when a haploid is doubled. Any diploidized haploid that shows a favourable change in a chemical trait automatically represents a potentially useful breeding line. Parasexual hybridization is a new technique that involves the fusion of protoplasts. Fusion of protoplasts between diploid tobacco and a species, that cannot be crossed with it by conventional means, provides a valuable new allopolyploid. Thus, conventional breeding methods aided by these new adjunct techniques provide the basis for favourably altering chemical constituents in the leaf and smoke.
- Accès libre
Methods to Determine Phytopharmaceuticals in Tobacco and Tobacco Products3rd Report: Rapid Determination of Fenamiphos and Fensulfothion/Methoden zur Bestimmung von Phytopharmaka in Tabak und Tabakerzeugnissen: III. Mitteilung: Eine schnelle Bestimmung von Fenamiphos und Fensulfothion
Pages: 107 - 110
A method was developed to rapidly determine fenamiphos and fensulfothion in tobacco. Using this procedure the two nematocides are extracted from the tobacco by chloroform, purified via an aluminium oxide column and then determined on the gas chromatograph.
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Methods to Determine Phytopharmaceuticals in Tobacco and Tobacco Products. 4th Report: A Procedure to Determine Vamidothion and its Metabolites/Methoden zur Bestimmung von Phytopharmaka in Tabak und Tabakerzeugnissen: IV. Mitteilung: Ein Bestimmungsverfahren fuer Vamidothion und seine Metaboliten
Pages: 111 - 115
Based on previous work (7) a method to simultaneously determine vamidothion [I], vamidothion-sulfoxide [II] and vamidothion sulfone [III] in tobacco has been developed. The compounds are extracted with water/acetone/acetic acid from the tobacco, cleansed over an aluminium oxide column and then determined on the gas chromatograph with the specific sulphur detector. Rates of recovery are 70 % - 92 %, the determination level is 0.1 ppm. Mass spectrometry and nuclear magnetic resonance data of vamidothion [I], vamidothion-sulfoxide [ II ] and vamidothion-sulfone [III] are given.