Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
  • A24B3/00—Preparing tobacco in the factory
  • A24B3/18—Other treatment of leaves, e.g. puffing, crimpling, cleaning
  • A24B3/182—Puffing

Definitions

• the present invention relates to a process for increasing the filling power of tobacco. More particularly, the present invention relates to a process for expanding tobacco which includes overwetting the tobacco with water and rapidly overdrying the overwetted tobacco in a turbulent steam atmosphere.
• the heretofore known expansion processes may be broadly characterized as involving penetration or impregnation of the tobacco with a blowing or puffing agent, sometimes referred to hereinafter as an "impregnant", which when removed during a subsequent expansion step generates elevated pressure in the tobacco and thereby causes expansion of the cell volume.
• the impregnant may be a solid, a liquid, or a gas.
• impregnants which have been employed are pressurized steam, air, water, organic solvents, ammonia, carbon dioxide, combinations of ammonia and carbon dioxide, and compounds capable of liberating a gas when subjected to chemical decomposition, as by heating. Where gases or other chemicals are utilized to cause or aid in expansion, physio-chemical changes may occur in the tobacco.
• oven volatiles is the percent weight loss of tobacco in a circulating air oven in three hours at 100°C. OV is used herein to mean the "moisture content" of the tobacco.
• filling power is the ability of the material to provide a firm rod.
• the filling power is the minimum weight of tobacco which will produce a tobacco rod of specified dimensions and firmness and may be measured as the volume occupied by a specified weight of filler in an upright cylinder when a specified piston weight is applied to its top surface, as set forth in "Filling Volume of Cut Tobacco and Cigarette Hardness", H. Wakeham, et al., Tobacco Science xx: 164-167, 1976. Standard equilibrium conditions for measurement of filling power are usually 60% relative humidity (RH) at 75°F (23.9°C).
• cylinder volume is a measurement of filling power and is determined by placing 10.0 grams of filler in a standard metal cylinder, 3.358 cm. in diameter, and vibrating the assembly for one-half minute to settle the tobacco column. The tobacco is then compressed under a piston weighing 1875 grams and having a diameter of 3.335 an, for , five minutes and the volume reading is then taken. The standard deviation of the cylinder volume measurement is about 1.5%.
• the present invention provides a process for expanding tobacco by means of overwetting the tobacco to a moisture content of at least 20% and then overdrying the tobacco in a period of a few seconds in a turbulent steam atmosphere to a moisture content below the moisture content normally encountered in processing. It has been determined that such overdrying must occur to a moisture content of less than 7% to achieve increased filling power.
• tobacco lamina or cut tobacco filler is moisturized to a moisture content of at least 20% which is above the moisture level of unprocessed tobacco and appreciably above the normal 12% processing moisture level of tobacco. It has been found that when tobacco having a moisture content above 20% is treated according to the process of the present invention, significant increases in filling power are achieved. At a moisture content of 20%, expansion may also be attained by rapidly overdrying the tobacco according to the process of the present invention, but the chemical and physical properties of the tobacco will have a greater influence on the effectiveness of the process.
• the moisture content of the tobacco is from 20% to about 80%, and more preferably from about 30% to about 80%, although moisture contents within the range of 20% to about 40% are effectively employed.
• Moisture contents of about 60% to about 80% may be effectively employed, but penetration or bulking time will probably increase and drying the tobacco within the desired times and to the desired post-treatment moisture levels will be more expensive and time consuming.
• the moisture be allowed to substantially uniformly penetrate and be distributed or dispersed throughout the cellular structure of the tobacco being processed, although homogeneous dispersion is not required.
• the bulking penetration time for satisfactory penetration will depend upon batch size and upon the means of addition of the water and the desired economics. Employing a rotary cylinder and a fine mist spray or other conventional mixing system known in the art for incorporating additives, a penetration time of 4 hours or somewhat less will be sufficient, as is further illustrated in Example 5.
• the primary criterion is that the time of penetration be sufficient to allow the moisture to be distributed within and absorbed by the tobacco cellular structure of substantial portions of the tobacco.
• the overwetted tobacco is bulked from about 1/4 hour to about 4 hours.
• the tobacco is overdried in a period of a few seconds in a turbulent steam atmosphere.
• overdrying in the context of the present invention means drying the overwetted tobacco to a moisture content below the moisture contents typically encountered and utilized in the processing of tobacco.
• the normal or conventional moisture content of tobacco to be processed, particularly that of commonly used tobacco filler, is usually approximately about 12% to about 21%.
• Rapid drying of the tobacco preferably within less than 5 seconds, in a turbulent steam atmosphere to a moisture content of less than 7% expands the tobacco as the moisture rapidly escapes the tobacco cellular structure.
• the cellular structure of the tobacco fibers thereupon stiffen to retain the expanded nature of the tobacco during remoisturization to normal processing moisture contents.
• the tobacco is dried to a moisture content of less than 5% and more preferably to a moisture content of less than 3%, with drying to a moisture content of 2% to 3% being particularly preferred.
• Steam drying versus air drying produces substantial gains in filling power as will be noted from Example 2.
• a high turbulence drying unit such as a Proctor & Schwartz dispersion dryer, or a Jetstream® dryer or other equivalent drying tower, capable of producing a turbulent atmosphere high in steam content, may be utilized.
• the proportion of steam in the turbulent steam drying atmosphere is desirably at least about 60%, and preferably at least about 80% although steam contents of about 60% to about 70% can be effectively employed.
• the treatment temperature that is, the temperature of the turbulent steam atmosphere in the drying unit
• the moisture content of the overwetted tobacco may be reduced to less than about 5% to produce economically significant increases in filling power. Rapid drying in a turbulent steam atmosphere at a treatment temperature of at least about 316°C, and preferably from about 316°C to about 330°C provides substantial increases in filling power.
• treatment temperatures of about 121°C provide little useful increase in filling power; temperatures from about 149°C to about 204°C provide perceptible gains in filling power; temperatures from about 232°C to about 288°C provide moderate increases in filling power, and temperature of from about 288°C to about 316°C provide significant increases in filling power.
• turbulent steam atmospheres having temperatures as high as 500°C. may be successfully utilized.
• the tobacco is preferably remoisturized under mild conditions, by means and processes well known in the industry for reordering tobacco, such as cylinder reordering, to achieve a processing moisture content of about 12%.
• the reordering should be at a moderate rate to prevent loss of expanded fiber rigidity.
• Example 2 50 pounds of bright filler were moisturized and bulked as in Example 1. Samples of the overwetted filler were processed in a steam atmosphere in a high turbulence drying tower at 121°C, 149°C, 177°C, 204°C, 232°C, 260°C, 288°C, 316°C and 330°C in a time period of 4 seconds or less. The results are summarized in Table 3 below and illustrate the significant gains in filling power which are achieved by overdrying the overwetted tobacco at elevated temperatures in a turbulent steam atmosphere.
• Example 1 Fifty pounds of bright filler were moisturized and equilibrated as in Example 1. The filler was allowed to bulk, and portions were removed after 1/4, 1/2, 1, 2, 3, 4 and 24 hours of bulking. The 7 sample portions were rapidly dried in a tower containing a turbulent steam atmosphere at 316°C. The results are summarized in Table 5 below.
• Example 1 Fifty pounds of bright filler were processed as in Example 1. The processed filler, after reordering, had a filling power of 56 cc/lOg, corrected to 12% moisture. Cigarettes were made in which 15% of the conventional filler was replaced by the processed filler and the subjective qualities of these cigarettes were compared with those of standard production cigarettes. There were no major subjective differences and the cigarettes containing the 15% expanded tobacco were found to be equally satisfying and to have full flavor.

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• Manufacture Of Tobacco Products (AREA)

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Cited By (3)

Citations (6)

• 1981
  • 1981-10-30 EP EP19810305197 patent/EP0078352B1/fr not_active Expired
• 1987
  • 1987-12-30 MY MY8700901A patent/MY8700901A/xx unknown

Patent Citations (6)

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