XV. CHEMICAL PROBLEMS IN CONNECTION WITH TOBACCO P n a M. GROSS,T ~ LICOSTT E AND MYERSTOBACCO FOUNDATTON, D m UNIVERSITY, DURR~M, NOR% CAROLINA
The tobacco industry in the United States has in the past had the benefit of information from scientific research only in connection with the fertilization of tobacco and to a limited extent in connection with the growing and processing of cigar tobaccos in certain restricted regions. Very little investigation has been carried out in connection with the growing, and more particularly, the processing of cigarette tobaccos of both the Virginia and Bnrley types grown in our southern states. As the raising of these types of tobacco is essentially a southern industry, it seems appropriate to draw attention to a number of fundamental problems connected with the industry which could be investigated in southern educational institutions and the solution of which should be of benefit to the industry and to the South. I have therefore outlined a number of problems which have presented themselves as suitable for investigation in the course of tobacco research carried out by myself and my associates. In surveying this situation, the essential distinction between cigar types of tobacco and cigarette types of tobacco must be emphasized as to methods of growing and particularly as to methods used in processing for manufacture. Most cigar tobaccos are fermented by providing suitable temperature and humidity conditions for an actual fermentation, the active organisms or enzymes being those originally present in the green leaf. Most cigarette tobacco on the contrary is processed by flue-curing, which is a drastic thermal treatment sufficient to destroy most of the organisms or enzymes which may have been present. Extensive investigations on the chemistry of cigar tobaccos have been carried out in Germany and in Austria, and are a t present being carried out a t Krasnodar in Southern Russia. As a general statement, it may be said, therefore, that the technic and methods of investigating cigar tobacco have been fairly well worked out, and that the application of these methods to the cigarette types of tobacco grown in this country presents a very wide and fruitful field for research, which to date has been barely touched upon. In addition to the desirability of repeating such investigations for cigarette types of tobacco, the following specific problems which are here set forth only in brief outline, would undoubtedly repay investigation. (1) A thorough study should be made of the chemical changes during the process of flue-curing of cigarette tobacco. This should include a study of the moisture changes, as well as the changes in carbohydrates, 2342
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total nitrogen, amine and amide nitrogen, and other constituents under controlled conditions of temperature and humidity during the curing process. (2) A n investigation of the effectof fumigants such as are used to control the tobacco beetle upon the tobacco itself ought to be carried out. This should include a study of the absorption of the fumigant by the tobacco in relation to the quantity of fumigant necessary for an effective kill, and a study of the retention of the fumigant by the tobacco as a function of temperature, moisture, and time. (3) Investigation should be made of the applicability of standard methods of analysis to tobacco. A knowledge of the changes necessary in these methods to make them so applicable would be very desirable. In particular an adequate method for the rapid estimation of moisture in both leaf and manufactured tobacco should be made available. (4) Though a number of studies of the rate of bum of cigar tobaccos have been made, comparatively few such studies have been made for cigarette tobaccos. An investigation of the factors affecting the rate of bum as related to the composition, and the fertilizers used in growing, presents a problem of great complexity, and one of considerable interest from the standpoint of physical chemistry. (5) A great number of isolation studies could be carried out upon cigarette tobacco with the aim of identifying the nature and constitution of compounds occurring in tobacco in any of the following classes: (a) alkaloids. (b) essential oils, (6) carbohydrates, (d) waxes. (6) Similarly, a great number of investigations in plant biochemistry suggest themselves since tobacco is in many respects an ideal plant for such investigations. Several of these may be mentioned: (a) the effect of the operation of topping in relation to the transfer of constituents in the growing plant both in the stalk and from leaf to leaf up the stalk; (b) a study of the factors determining the reversion to type of plants grown in this country from imported seed, such as that of Turkish tobaccos; (6) a study of the effect of varying fertilizers on the actual composition of the whole plant; (d) the influence of various amounts of nitrogen and potassium on the distribution of nicotine in the plant; (e) the translocation of potassium or other mineral constituents such as calcium and magnesium in tobacco plants and its relation to their carbohydrate and nitrogen distribution; (f) the influence of chlorine on the general composition of tobacco leaves. (7) A number of biometric studies could be conveniently carried out in connection with tobacco because of its wide distribution. A study of the relation between the carbohydrate development in the plant and its geographical distribution with respect to temperature, water supply, and atmospheric humidity would be desirable from an economic as well as agricultural standpoint.
