Rivista e Edizione

Volume 31 (2022): Edizione 2 (July 2022)

Volume 31 (2022): Edizione 1 (March 2022)

Volume 30 (2021): Edizione 4 (November 2021)

Volume 30 (2021): Edizione 3 (July 2021)

Volume 30 (2021): Edizione 2 (May 2021)

Volume 30 (2021): Edizione 1 (March 2021)

Volume 29 (2020): Edizione 3 (December 2020)

Volume 29 (2020): Edizione 2 (August 2020)

Volume 29 (2020): Edizione 1 (April 2020)

Volume 28 (2019): Edizione 7 (December 2019)

Volume 28 (2019): Edizione 6 (August 2019)

Volume 28 (2019): Edizione 5 (May 2019)

Volume 28 (2018): Edizione 4 (December 2018)

Volume 28 (2018): Edizione 3 (October 2018)

Volume 28 (2018): Edizione 2 (August 2018)

Volume 28 (2018): Edizione 1 (April 2018)

Volume 27 (2017): Edizione 8 (December 2017)

Volume 27 (2017): Edizione 7 (September 2017)

Volume 27 (2017): Edizione 6 (April 2017)

Volume 27 (2017): Edizione 5 (January 2017)

Volume 27 (2016): Edizione 4 (October 2016)

Volume 27 (2016): Edizione 3 (July 2016)

Volume 27 (2016): Edizione 2 (April 2016)

Volume 27 (2016): Edizione 1 (January 2016)

Volume 26 (2015): Edizione 7 (September 2015)

Volume 26 (2015): Edizione 6 (June 2015)

Volume 26 (2015): Edizione 5 (March 2015)

Volume 26 (2014): Edizione 4 (December 2014)

Volume 26 (2014): Edizione 3 (September 2014)

Volume 26 (2014): Edizione 2 (July 2014)

Volume 26 (2014): Edizione 1 (April 2014)

Volume 25 (2013): Edizione 8 (December 2013)

Volume 25 (2013): Edizione 7 (September 2013)

Volume 25 (2013): Edizione 6 (June 2013)

Volume 25 (2013): Edizione 5 (March 2013)

Volume 25 (2012): Edizione 4 (December 2012)

Volume 25 (2012): Edizione 3 (August 2012)

Volume 25 (2012): Edizione 2 (June 2012)

Volume 25 (2012): Edizione 1 (February 2012)

Volume 24 (2011): Edizione 6 (November 2011)

Volume 24 (2011): Edizione 5 (May 2011)

Volume 24 (2011): Edizione 4 (January 2011)

Volume 24 (2010): Edizione 3 (November 2010)

Volume 24 (2010): Edizione 2 (July 2010)

Volume 24 (2010): Edizione 1 (April 2010)

Volume 23 (2009): Edizione 6 (December 2009)

Volume 23 (2009): Edizione 5 (September 2009)

Volume 23 (2009): Edizione 4 (May 2009)

Volume 23 (2008): Edizione 3 (December 2008)

Volume 23 (2008): Edizione 2 (August 2008)

Volume 23 (2008): Edizione 1 (April 2008)

Volume 22 (2007): Edizione 5 (June 2007)

Volume 22 (2007): Edizione 4 (January 2007)

Volume 22 (2006): Edizione 3 (October 2006)

Volume 22 (2006): Edizione 2 (July 2006)

Volume 22 (2006): Edizione 1 (April 2006)

Volume 21 (2005): Edizione 8 (December 2005)

Volume 21 (2005): Edizione 7 (October 2005)

Volume 21 (2005): Edizione 6 (July 2005)

Volume 21 (2005): Edizione 5 (April 2005)

Volume 21 (2004): Edizione 4 (December 2004)

Volume 21 (2004): Edizione 3 (October 2004)

Volume 21 (2004): Edizione 2 (July 2004)

Volume 21 (2004): Edizione 1 (March 2004)

Volume 20 (2003): Edizione 8 (December 2003)

Volume 20 (2003): Edizione 7 (November 2003)

Volume 20 (2003): Edizione 6 (July 2003)

Volume 20 (2003): Edizione 5 (March 2003)

Volume 20 (2002): Edizione 4 (December 2002)

Volume 20 (2002): Edizione 3 (August 2002)

Volume 20 (2002): Edizione 2 (June 2002)

Volume 20 (2002): Edizione 1 (February 2002)

Volume 19 (2001): Edizione 7 (October 2001)

Volume 19 (2001): Edizione 6 (July 2001)

Volume 19 (2001): Edizione 5 (April 2001)

Volume 19 (2001): Edizione 4 (January 2001)

Volume 19 (2000): Edizione 3 (October 2000)

Volume 19 (2000): Edizione 2 (July 2000)

Volume 19 (2000): Edizione 1 (April 2000)

Volume 18 (1999): Edizione 6 (December 1999)

Volume 18 (1999): Edizione 5 (July 1999)

Volume 18 (1999): Edizione 4 (April 1999)

Volume 18 (1998): Edizione 3 (December 1998)

Volume 18 (1998): Edizione 2 (August 1998)

Volume 18 (1998): Edizione 1 (April 1998)

Volume 17 (1997): Edizione 3 (December 1997)

Volume 17 (1997): Edizione 2 (September 1997)

Volume 17 (1996): Edizione 1 (December 1996)

Volume 16 (1995): Edizione 4 (November 1995)

Volume 16 (1995): Edizione 3 (July 1995)

Volume 16 (1994): Edizione 2 (June 1994)

Volume 16 (1994): Edizione 1 (May 1994)

Volume 15 (1992): Edizione 3 (November 1992)

Volume 15 (1992): Edizione 2 (April 1992)

Volume 15 (1991): Edizione 1 (August 1991)

Volume 14 (1990): Edizione 6 (June 1990)

Volume 14 (1989): Edizione 5 (October 1989)

Volume 14 (1989): Edizione 4 (February 1989)

Volume 14 (1989): Edizione 3 (January 1989)

Volume 14 (1988): Edizione 2 (October 1988)

Volume 14 (1987): Edizione 1 (December 1987)

Volume 13 (1986): Edizione 5 (December 1986)

Volume 13 (1986): Edizione 4 (August 1986)

Volume 13 (1986): Edizione 3 (July 1986)

Volume 13 (1985): Edizione 2 (December 1985)

Volume 13 (1985): Edizione 1 (January 1985)

Volume 12 (1984): Edizione 5 (November 1984)

Volume 12 (1984): Edizione 4 (July 1984)

Volume 12 (1984): Edizione 3 (February 1984)

Volume 12 (1983): Edizione 2 (June 1983)

Volume 12 (1983): Edizione 1 (February 1983)

Volume 11 (1982): Edizione 5 (November 1982)

Volume 11 (1982): Edizione 4 (August 1982)

Volume 11 (1982): Edizione 3 (January 1982)

Volume 11 (1981): Edizione 2 (September 1981)

Volume 11 (1981): Edizione 1 (March 1981)

Volume 10 (1980): Edizione 3 (October 1980)

Volume 10 (1980): Edizione 2 (July 1980)

Volume 10 (1979): Edizione 1 (December 1979)

Volume 9 (1978): Edizione 5 (December 1978)

Volume 9 (1978): Edizione 4 (July 1978)

Volume 9 (1977): Edizione 3 (October 1977)

Volume 9 (1977): Edizione 2 (June 1977)

Volume 9 (1977): Edizione 1 (April 1977)

Volume 8 (1976): Edizione 7 (October 1976)

Volume 8 (1976): Edizione 6 (June 1976)

Volume 8 (1976): Edizione 5 (March 1976)

Volume 8 (1975): Edizione 4 (December 1975)

Volume 8 (1975): Edizione 3 (August 1975)

Volume 8 (1975): Edizione 2 (May 1975)

Volume 8 (1975): Edizione 1 (January 1975)

Volume 7 (1974): Edizione 5 (September 1974)

Volume 7 (1974): Edizione 4 (April 1974)

Volume 7 (1973): Edizione 3 (November 1973)

Volume 7 (1973): Edizione 2 (June 1973)

Volume 7 (1973): Edizione 1 (January 1973)

Volume 6 (1972): Edizione 5 (October 1972)

Volume 6 (1972): Edizione 4 (August 1972)

Volume 6 (1972): Edizione 3 (March 1972)

Volume 6 (1971): Edizione 2 (September 1971)

Volume 6 (1971): Edizione 1 (July 1971)

Volume 5 (1970): Edizione 6 (December 1970)

Volume 5 (1970): Edizione 5 (November 1970)

Volume 5 (1970): Edizione 4 (August 1970)

Volume 5 (1969): Edizione 3 (December 1969)

Volume 5 (1969): Edizione 2 (August 1969)

Volume 5 (1969): Edizione 1 (June 1969)

Volume 4 (1968): Edizione 7 (December 1968)

Volume 4 (1968): Edizione 6 (November 1968)

Volume 4 (1968): Edizione 5 (July 1968)

Volume 4 (1968): Edizione 4 (May 1968)

Volume 4 (1968): Edizione 3 (February 1968)

Volume 4 (1967): Edizione 2 (October 1967)

Volume 4 (1967): Edizione 1 (August 1967)

Volume 3 (1966): Edizione 9 (December 1966)

Volume 3 (1966): Edizione 8 (December 1966)

Volume 3 (1966): Edizione 7 (November 1966)

Volume 3 (1966): Edizione 6 (September 1966)

Volume 3 (1966): Edizione 5 (May 1966)

Volume 3 (1965): Edizione 4 (October 1965)

Volume 3 (1965): Edizione 3 (August 1965)

Volume 3 (1965): Edizione 2 (May 1965)

Volume 3 (1965): Edizione 1 (April 1965)

Volume 2 (1964): Edizione 7 (November 1964)

Volume 2 (1964): Edizione 6 (October 1964)

Volume 2 (1964): Edizione 5 (May 1964)

Volume 2 (1964): Edizione 4 (February 1964)

Volume 2 (1963): Edizione 3 (October 1963)

Volume 2 (1963): Edizione 2 (June 1963)

Volume 2 (1963): Edizione 1 (March 1963)

Volume 1 (1962): Edizione 10 (December 1962)

Volume 1 (1962): Edizione 9 (December 1962)

Volume 1 (1962): Edizione 8 (November 1962)

Volume 1 (1962): Edizione 7 (November 1962)

Volume 1 (1962): Edizione 6 (July 1962)

Volume 1 (1962): Edizione 5 (February 1962)

Volume 1 (1961): Edizione 4 (November 1961)

Volume 1 (1961): Edizione 3 (August 1961)

Volume 1 (1961): Edizione 2 (May 1961)

Volume 1 (1961): Edizione 1 (January 1961)

Dettagli della rivista
Formato
Rivista
eISSN
2719-9509
Pubblicato per la prima volta
01 Jan 1992
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

Volume 8 (1975): Edizione 1 (January 1975)

Dettagli della rivista
Formato
Rivista
eISSN
2719-9509
Pubblicato per la prima volta
01 Jan 1992
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

8 Articoli
Accesso libero

Contribution to Defining Pressure Drop/Zur Definition des Zugwiderstandes

Pubblicato online: 13 Aug 2014
Pagine: 1 - 6

Astratto

Abstract

With constant volumetric flow rate F at the end of the test specimen the pressure drop is dependent on the absolute pressure under which the volumetric flow rate is measured. The correlation between pressure drop Dp at the test specimen and volumetric flow rate F can be adequately described by

in which k is a constant for a certain object measured and p* designates the pressure under which the volumetric flow rate F is measured. p1 and p2 are the absolute pressures at the test specimen entrance and exit respectively. For the definition of draw resistance it results from this that the Coresta suggestion that p1 = 1 atm 760 Torr be determined as reference pressure is inexpedient for practical purposes. It would be more expedient to determine p* = p2 = 1 atm 760 Torr, i. e. that pressure is determined as reference pressure under which the volumetric flow rate F is measured at the end of the test specimen. The simple correction formulae resulting for this with fluctuating atmospheric pressure are quoted.

Accesso libero

The Effect of the Natural Sugar Content of Tobacco Upon the Acetaldehyde Concentration found in Cigarette Smoke

Pubblicato online: 13 Aug 2014
Pagine: 7 - 10

Astratto

Abstract

All the evidence obtained in our laboratories has shown that the total aldehyde yield in tobacco smoke is not related to either sugar content or the equilibrium moisture content of the tobaccos. There is, however, a relationship between particulate matter [PM(WNF)]+ and aldehyde delivery. This accounts for some 41 % of the total variation between different cigarettes. + PM(WMF) = Total particulate matter - (water + nicotine)

Accesso libero

Some Effects of Adding Sugar to Tobacco

Pubblicato online: 13 Aug 2014
Pagine: 11 - 15

Astratto

Abstract

A series of cigarettes made from Burley tobacco containing different levels of added reducing sugar (10.5 to 17.8 %) have been examined. Compared to the control cigarette there was virtually no change in the deliveries of aldehydes and carbonyl constituents. However, an increase in the delivery of 2-furfural was observed, especially when fructose was the added sugar: even so, the conversion efficiency was only 1-2 %. A similar increase in the delivery of 2-furfural was also observed when glucose was added to flue-cured tobacco. An additional finding was that the addition of glucose and fructose reduced the delivery of nicotine. Radioactivity balance experiments on flue-cured cigarettes with added glucose indicated that this was probably due to an increase in the nicotine filtration efficiency of the cigarette rod. Filtration studies using air-cured cigarettes demonstrated that, on addition of glucose, there was a significant increase in the nicotine filtration efficiency of the tobacco rod and that less of the available nicotine was directed into the mainstream.

Accesso libero

The Formation of the Oxides of Carbon by the Pyrolysis of Tobacco

Pubblicato online: 13 Aug 2014
Pagine: 16 - 27

Astratto

Abstract

Flue-cured Virginia tobacco has been heated in nitrogen and nitrogen/oxygen mixtures under flow conditions, and the rate of formation of carbon monoxide and carbon dioxide has been determined as a function of temperature, heating rate, and proportion of oxygen in the gas. When the tobacco is heated in nitrogen at heating rates comparable to those in a smouldering cigarette, 27 % of the carbon content of the tobacco is converted to carbon oxides. Both carbon oxides show two distinct formation regions: a low-temperature region (about 100°-450°C), and a high-temperature region (about 550°-900°C). These temperature limits are almost identical to those predicted from studies on the combustion coal of a cigarette burning in air. When tobacco, or the carbonaceous residue remaining after the pyrolysis experiments, is heated in nitrogen / oxygen mixtures, the total amount of carbon converted to carbon monoxide and carbon dioxide is independent of heating rate, but the relative proportions of the two oxides are strongly dependent on heating rate. At the lower heating rate, proportionally less carbon monoxide, and more carbon dioxide, is produced. Under oxidation conditions, about 70 % of both carbon oxides formed in the low-temperature region (100°-450°C) are produced by tobacco decomposition reactions, whereas in the high-temperature region about 10-20 % of the carbon monoxide, and 2-9 % of the carbon dioxide, are produced by tobacco decomposition.

Accesso libero

The Antioxidant Activity of Tobacco Smoke

Pubblicato online: 13 Aug 2014
Pagine: 28 - 33

Astratto

Abstract

Cigarette smoke has been shown to contain free radicals in both the vapour and particulate phases. The present investigation was undertaken to find out whether these radicals could initiate or promote the formation of radical peroxides which might in turn lead to lipid peroxidation. To investigate this, a system involving the coupled oxidation of b-carotene and linoleic acid was utilized. In this coupled reaction, b-carotene is destroyed through oxidation by free peroxy radicals. The system can therefore be used as a convenient detector of auto-oxidative mechanisms in which peroxide radicals participate, as well as provide an assay for antioxidants, since in their presence oxidative destruction of b-carotene is blocked. Our results show that smoke did not contribute to the oxidative destruction of b-carotene but rather behaved as an antioxidant. Both smoke vapour and particulate matter were found to be highly antioxidant. A number of pure vapour phase components were tested and the bulk of antioxidant activity was found to be due to HCN. Smoke condensates from different tobacco types were compared and differentiated according to their relative efficiencies of antioxidant activities. For comparison, units of antioxidant activity were expressed as rate of change of optical density with time. The highest antioxidant activities were obtained with air-, flue-cured (cut) and perique tobaccos. Pipe tobacco had the least activity while cigar and flue-cured (granulated), stem and sheet tobaccos had intermediate values. Tests done on smoke fractions derived from the fractionation of total condensate revealed that antioxidant activity resided largely in the neutral and water-insoluble acid fractions with virtually no activity in the basic fractions. The mode of antioxidant action of tobacco smoke is discussed in terms of free-radical mechanisms.

Accesso libero

Some Agronomic Factors Affecting N-Dimethyl-nitrosamine Content in Cigarette Smoke

Pubblicato online: 13 Aug 2014
Pagine: 34 - 38

Astratto

Abstract

ExperimentaI cigarettes from tobaccos varying in genotype, nitrogen nutrition, stalk position, suckering practice, and curing methods were used to examine the Ievels of N-dimethylnitrosamine (DMN) in smoke. Measurable amounts of DMN were found in all experimental samples, ranging from 1.7 to 115 ng per gram of tobacco burned. DMN content in smoke generally increased as rate of N fertilization increased. However, there were wide seasonal, cultural, and varietal effects. Burley-type tobacco produced a much higher level of DMN than the bright-type tobacco. DMN content in smoke was significantly and positively related to Ieaf total N, totaI alkaloids, nicotine, nornicotine, total volatile bases and nitrate N, but negatively related to reducing sugars. Reconstituted sheet tobaccos made with homogenized-leaf-curing samples produced much lower amounts of DMN than conventionally cured leaf. Additional information is needed to elucidate the primary leaf constituents that serve as precursors of DMN.

Accesso libero

Insecticide Residues on 1972 U.S. Auction-Market Tobacco

Pubblicato online: 13 Aug 2014
Pagine: 39 - 43

Astratto

Abstract

Average residue Ievels of DDT + TDE in flue-cured tobacco decreased from 6.1 ppm in 1970 to 0.85 ppm in 1972. DDT + TDE residues in Burley also dropped sharply from previous levels. In 1972 one sample from Kentucky contained 8.17 ppm; all other Burley samples were less than 0.25 ppm. DDT + TDE residues also declined in fire-cured and air-cured types; of these samples Tennessee dark air-cured tobacco contained the highest average residue (3.5 ppm of DDT + TDE). In 1972 over 90 % of the flue-cured samples were positive for toxaphene. Since each of our samples was a composite of tobacco from 10 farmers, we cannot conclude from this result that 90 % of the individual piles contained toxaphene. Significant amounts of toxaphene were found in other types also; for example, 50 % of the 1972 Burley samples had toxaphene concentrations greater than 0.5 ppm. Average endosulfan levels decreased between 1970 and 1972 in flue-cured and Burley tobaccos. However, in all of the dark air and dark fire-cured samples from Tennessee endosulfan residues exceeded 5 ppm. Average endrin residues were at or near the low detection limit in alI samples except fire-cured and dark air-cured tobacco from Tennessee; these averaged 0.26 and 0.17 ppm, respectively.

Accesso libero

Homogenized Leaf Curing: I. TheoreticaI Basis and Some Preliminary Results

Pubblicato online: 13 Aug 2014
Pagine: 44 - 51

Astratto

Abstract

A new procedure (HLC) of curing tobacco leaf through homogenization, incubation, and dehydration is described. At the homogenate stage, chemicaI composition can be improved by controlled enzyme action, by extraction, or with chemical additives. PhysicaI properties can be improved by reconstitution. Preliminary results show HLC may provide smoke with quality comparable to that from conventionally cured material, but with relatively lower biologicaI response. There is a great potential in using the HLC procedure for labour saving as well as for improving leaf usability.

8 Articoli
Accesso libero

Contribution to Defining Pressure Drop/Zur Definition des Zugwiderstandes

Pubblicato online: 13 Aug 2014
Pagine: 1 - 6

Astratto

Abstract

With constant volumetric flow rate F at the end of the test specimen the pressure drop is dependent on the absolute pressure under which the volumetric flow rate is measured. The correlation between pressure drop Dp at the test specimen and volumetric flow rate F can be adequately described by

in which k is a constant for a certain object measured and p* designates the pressure under which the volumetric flow rate F is measured. p1 and p2 are the absolute pressures at the test specimen entrance and exit respectively. For the definition of draw resistance it results from this that the Coresta suggestion that p1 = 1 atm 760 Torr be determined as reference pressure is inexpedient for practical purposes. It would be more expedient to determine p* = p2 = 1 atm 760 Torr, i. e. that pressure is determined as reference pressure under which the volumetric flow rate F is measured at the end of the test specimen. The simple correction formulae resulting for this with fluctuating atmospheric pressure are quoted.

Accesso libero

The Effect of the Natural Sugar Content of Tobacco Upon the Acetaldehyde Concentration found in Cigarette Smoke

Pubblicato online: 13 Aug 2014
Pagine: 7 - 10

Astratto

Abstract

All the evidence obtained in our laboratories has shown that the total aldehyde yield in tobacco smoke is not related to either sugar content or the equilibrium moisture content of the tobaccos. There is, however, a relationship between particulate matter [PM(WNF)]+ and aldehyde delivery. This accounts for some 41 % of the total variation between different cigarettes. + PM(WMF) = Total particulate matter - (water + nicotine)

Accesso libero

Some Effects of Adding Sugar to Tobacco

Pubblicato online: 13 Aug 2014
Pagine: 11 - 15

Astratto

Abstract

A series of cigarettes made from Burley tobacco containing different levels of added reducing sugar (10.5 to 17.8 %) have been examined. Compared to the control cigarette there was virtually no change in the deliveries of aldehydes and carbonyl constituents. However, an increase in the delivery of 2-furfural was observed, especially when fructose was the added sugar: even so, the conversion efficiency was only 1-2 %. A similar increase in the delivery of 2-furfural was also observed when glucose was added to flue-cured tobacco. An additional finding was that the addition of glucose and fructose reduced the delivery of nicotine. Radioactivity balance experiments on flue-cured cigarettes with added glucose indicated that this was probably due to an increase in the nicotine filtration efficiency of the cigarette rod. Filtration studies using air-cured cigarettes demonstrated that, on addition of glucose, there was a significant increase in the nicotine filtration efficiency of the tobacco rod and that less of the available nicotine was directed into the mainstream.

Accesso libero

The Formation of the Oxides of Carbon by the Pyrolysis of Tobacco

Pubblicato online: 13 Aug 2014
Pagine: 16 - 27

Astratto

Abstract

Flue-cured Virginia tobacco has been heated in nitrogen and nitrogen/oxygen mixtures under flow conditions, and the rate of formation of carbon monoxide and carbon dioxide has been determined as a function of temperature, heating rate, and proportion of oxygen in the gas. When the tobacco is heated in nitrogen at heating rates comparable to those in a smouldering cigarette, 27 % of the carbon content of the tobacco is converted to carbon oxides. Both carbon oxides show two distinct formation regions: a low-temperature region (about 100°-450°C), and a high-temperature region (about 550°-900°C). These temperature limits are almost identical to those predicted from studies on the combustion coal of a cigarette burning in air. When tobacco, or the carbonaceous residue remaining after the pyrolysis experiments, is heated in nitrogen / oxygen mixtures, the total amount of carbon converted to carbon monoxide and carbon dioxide is independent of heating rate, but the relative proportions of the two oxides are strongly dependent on heating rate. At the lower heating rate, proportionally less carbon monoxide, and more carbon dioxide, is produced. Under oxidation conditions, about 70 % of both carbon oxides formed in the low-temperature region (100°-450°C) are produced by tobacco decomposition reactions, whereas in the high-temperature region about 10-20 % of the carbon monoxide, and 2-9 % of the carbon dioxide, are produced by tobacco decomposition.

Accesso libero

The Antioxidant Activity of Tobacco Smoke

Pubblicato online: 13 Aug 2014
Pagine: 28 - 33

Astratto

Abstract

Cigarette smoke has been shown to contain free radicals in both the vapour and particulate phases. The present investigation was undertaken to find out whether these radicals could initiate or promote the formation of radical peroxides which might in turn lead to lipid peroxidation. To investigate this, a system involving the coupled oxidation of b-carotene and linoleic acid was utilized. In this coupled reaction, b-carotene is destroyed through oxidation by free peroxy radicals. The system can therefore be used as a convenient detector of auto-oxidative mechanisms in which peroxide radicals participate, as well as provide an assay for antioxidants, since in their presence oxidative destruction of b-carotene is blocked. Our results show that smoke did not contribute to the oxidative destruction of b-carotene but rather behaved as an antioxidant. Both smoke vapour and particulate matter were found to be highly antioxidant. A number of pure vapour phase components were tested and the bulk of antioxidant activity was found to be due to HCN. Smoke condensates from different tobacco types were compared and differentiated according to their relative efficiencies of antioxidant activities. For comparison, units of antioxidant activity were expressed as rate of change of optical density with time. The highest antioxidant activities were obtained with air-, flue-cured (cut) and perique tobaccos. Pipe tobacco had the least activity while cigar and flue-cured (granulated), stem and sheet tobaccos had intermediate values. Tests done on smoke fractions derived from the fractionation of total condensate revealed that antioxidant activity resided largely in the neutral and water-insoluble acid fractions with virtually no activity in the basic fractions. The mode of antioxidant action of tobacco smoke is discussed in terms of free-radical mechanisms.

Accesso libero

Some Agronomic Factors Affecting N-Dimethyl-nitrosamine Content in Cigarette Smoke

Pubblicato online: 13 Aug 2014
Pagine: 34 - 38

Astratto

Abstract

ExperimentaI cigarettes from tobaccos varying in genotype, nitrogen nutrition, stalk position, suckering practice, and curing methods were used to examine the Ievels of N-dimethylnitrosamine (DMN) in smoke. Measurable amounts of DMN were found in all experimental samples, ranging from 1.7 to 115 ng per gram of tobacco burned. DMN content in smoke generally increased as rate of N fertilization increased. However, there were wide seasonal, cultural, and varietal effects. Burley-type tobacco produced a much higher level of DMN than the bright-type tobacco. DMN content in smoke was significantly and positively related to Ieaf total N, totaI alkaloids, nicotine, nornicotine, total volatile bases and nitrate N, but negatively related to reducing sugars. Reconstituted sheet tobaccos made with homogenized-leaf-curing samples produced much lower amounts of DMN than conventionally cured leaf. Additional information is needed to elucidate the primary leaf constituents that serve as precursors of DMN.

Accesso libero

Insecticide Residues on 1972 U.S. Auction-Market Tobacco

Pubblicato online: 13 Aug 2014
Pagine: 39 - 43

Astratto

Abstract

Average residue Ievels of DDT + TDE in flue-cured tobacco decreased from 6.1 ppm in 1970 to 0.85 ppm in 1972. DDT + TDE residues in Burley also dropped sharply from previous levels. In 1972 one sample from Kentucky contained 8.17 ppm; all other Burley samples were less than 0.25 ppm. DDT + TDE residues also declined in fire-cured and air-cured types; of these samples Tennessee dark air-cured tobacco contained the highest average residue (3.5 ppm of DDT + TDE). In 1972 over 90 % of the flue-cured samples were positive for toxaphene. Since each of our samples was a composite of tobacco from 10 farmers, we cannot conclude from this result that 90 % of the individual piles contained toxaphene. Significant amounts of toxaphene were found in other types also; for example, 50 % of the 1972 Burley samples had toxaphene concentrations greater than 0.5 ppm. Average endosulfan levels decreased between 1970 and 1972 in flue-cured and Burley tobaccos. However, in all of the dark air and dark fire-cured samples from Tennessee endosulfan residues exceeded 5 ppm. Average endrin residues were at or near the low detection limit in alI samples except fire-cured and dark air-cured tobacco from Tennessee; these averaged 0.26 and 0.17 ppm, respectively.

Accesso libero

Homogenized Leaf Curing: I. TheoreticaI Basis and Some Preliminary Results

Pubblicato online: 13 Aug 2014
Pagine: 44 - 51

Astratto

Abstract

A new procedure (HLC) of curing tobacco leaf through homogenization, incubation, and dehydration is described. At the homogenate stage, chemicaI composition can be improved by controlled enzyme action, by extraction, or with chemical additives. PhysicaI properties can be improved by reconstitution. Preliminary results show HLC may provide smoke with quality comparable to that from conventionally cured material, but with relatively lower biologicaI response. There is a great potential in using the HLC procedure for labour saving as well as for improving leaf usability.

Pianifica la tua conferenza remota con Sciendo