It is well known that the physicaI characteristics of natural fibers, particularly those of vegetable or cellulosic origin, can be controlled within well-defined limits by the chemicaI pulping methods and by the degree of refining to which they are subjected. It has been found that when such materials are subjected to a mild chemical treatment for the isolation of the cellulose, the isolated cellulose fiber, under microscopic analysis, has retained its physicaI identity despite the chemicaI exposures. This technique has been successfully applied to reconstituted tobacco as a means of identifying the source of the cellulose used in its manufacture. Not only can the source of the cellulose be determined as being from tobacco or wood, but the degree of refining to which these constituents were subjected prior to conversion into the reconstituted product can be easily ascertained. Photomicrographic proof for the validity of these statements is presented
From an investigation of a variety of methods for visualisation of the shred structure in a cigarette, it has been shown that two optical and one x-radiographic method produce useful information. It is concluded that the x-radiographic method, especially by the use of stereo views, provides the most information; it is a convenient and easily utilized method. Examination of a limited number of commercial cigarettes did not show any recognizable structural differences beyond fluctuations in rod density. Novel structures utilizing low-density materials can be readily distinguished.
While it is known that ionizing radiation can bring about chemical, biological and physical changes in organic tissue, relatively little is known concerning radiation effects on tobacco and its combustion products. In an effort to study such changes, Virginia bright tobacco was exposed to ionizing radiation at doses up to 50 Mrads, generated electronically by a high-voltage discharge. It was found that tobacco exposed to this high radiation will undergo physical changes such as a darkening, an increase in brittleness, puffing of the stems and a change in aroma characteristics. Chemical changes were found in selected chemicaI components such as water and solvent solubles, nicotine, reducing sugars, dextrin, cellulose, pectin, tannins and lignin. Both physical and chemical changes seem to be dose dependent. Studies on smoke components from cigarettes of both irradiated and non-irradiated tobacco indicate that irradiation had no major effects on the components of the gas phase examined and only minor effects on the composition of the particulate phase.