Beiträge zur Tabakforschung International/Contributions to Tobacco Research Volume 20 # No. 4 # December 2002 Some Studies of the Effects of Additives on Cigarette Mainstream Smoke Properties. II. Casing Materials and Humectants* by Alan Rodgman 2828 Birchwood Drive Winston-Salem, North Carolina, 27103-3410, USA CONTENTS ZUSAMMENFASSUNG Summary ................................................................... 279 Die Überprüfung umfangreicher Untersuchungsergebnisse 1 Introduction ........................................................ 280 der letzten vier Jahrzehnte, insbesondere nicht publizierte 2 Casing materials ................................................. 281 Daten aus den fünfziger und sechziger Jahren, weisen 2.1 Sugars ................................................................. 281 darauf hin, dass keine der Substanzen, die als Sossierungs- 2.2 Licorice ............................................................... 284 mittel (Zucker, Lakritze, Kakao) und Feuchthaltemittel 2.3 Cocoa .................................................................. 285 (Glycerin, Propylenglykol, andere Glykole) zu Tabakpro- 3 Humectants ......................................................... 287 dukten, insbesondere Cigaretten, zugegeben wurden, signi- 4 Conclusions ........................................................ 292 fikant nachteilige chemische oder biologische Wirkungen References ................................................................. 292 auf den Hauptstromrauch (HSR) dieser Cigaretten haben. Zu dieser Schlussfolgerung kamen DOULL et al. (1) in ihrer Beurteilung der zur Verfügung stehenden Informationen SUMMARY über annähernd 600 Aromatisierungs-, Sossierungs- und Feuchthaltemittel, die von der US-amerikanischen Tabakin- Examination of extensive laboratory data collected during dustrie als Zusatzstoffe für Cigarettentabak benutzt wurden. the past four decades, particularly those unpublished data Der Gesamtgehalt an polycyclischen aromatischen Kohlen- generated in the 1950s and 1960s, indicates that none of the wasserstoffen (PAHs) oder Benzo[a]pyren (B[a]P) im materials used as casing materials (sugars, licorice, cocoa) HSR, denen viele Jahre lang besonderes Interesse galt, er- and humectants (glycerol, propylene glycol, other glycols) höhte sich durch die Zugabe von Sossierungs- und Feucht- on smoking tobacco products, particularly cigarettes, haltemitteln zum Cigarettentabak nicht signifikant. Die imparts any significant adverse chemical or biological pro- Untersuchung des Übergangs von Feuchthaltemitteln aus perties to the mainstream smoke (MSS) from cased and dem behandelten Tabak in den HSR der Cigaretten weist humectant-treated tobacco, a conclusion reached by DOULL darauf hin, dass die Feuchthaltemittel auf die verbleibenden et al. (1) in their assessment of available information on Partikelphasenbestandteile des HSR, die während des nearly 600 flavorant, casing material, and humectant in- Rauchvorgangs produziert werden, signifikant verdünnend gredients variously used as cigarette tobacco additives in the wirken. Diese Verdünnung vermindert die Wirkungen, die U.S. Tobacco Industry. in mehreren Bioassays, z.B. Mutagenität bestimmt durch Addition of casing materials and humectants to the cigarette den Ames Salmonella typhimurium Test, beobachtet tobacco blend produced no significant increase in the wurden. [Beitr. Tabakforsch. Int. 20 (2002) 279–99] cigarette MSS of either the total polycyclic aromatic hydro- carbon (PAH) or the benzo[a]pyrene (B[a]P) content, MSS components that have been of considerable interest for many RESUME years. Examination of the transfer of humectants from the humectant-treated tobacco to cigarette MSS indicates that L’examen des résultats obtenus au cours des quatre derniè- the humectants act as significant diluents to the remaining res décennies, et surtout les données non-publiées des MSS particulate-phase components generated from the années 1950 et 1960, indiquent que les substances utilisées tobacco during the smoking process. This dilution decreases pour le sauçage (sucres, réglisse, cacao) et les humectants the effects observed in several bioassays, e.g., mutagenicity (glycérol, propylèneglycol, autres glycols) des produits de determined in the Ames Salmonella typhimurium test. tabacs, surtout des cigarettes, n’ont pas d’effets chimiques [Beitr. Tabakforsch. Int. 20 (2002) 279–99] *Received: 20th February 2001 – accepted: 22nd April 2002 279 Figure 1. Glycyrrhizic acid and benz[a]chrysene ou biologiques significativement défavorables sur les pro- burley, and Oriental tobaccos in the Camel 70-mm priétés de la fumée du courant principal (CP) des tabacs cigarette introduced by the R. J. Reynolds Tobacco auxquels ont été ajoutés ces substances. C’est la conclusion Company (RJRT) in 1913. à laquelle aboutissent DOULL et al. dans leur évaluation des It has been known for some years that a portion of the informations disponibles sur près de 600 ingrédients simple sugars such as glucose and fructose, either apportés au tabac comme aromatisant, sauce et humectant added to or inherent in the tobacco constituting the par l’industrie du tabac aux Etats Unis. blend, is transferred to cigarette mainstream smoke Il a été déterminé que l’apport de sauces et d’humectants au (MSS) (4,5). The role of sugars in maintaining accept- tabac des cigarettes n’entraîne pas une augmentation signi- ability of cigarette MSS to the consumer is described ficative de la teneur en hydrocarbures polycycliques aroma- by LEFFINGWELL et al. (3). tiques (PAH) ou en benzo[a]pyrene (B[a]P) du CP, compo- Because licorice and cocoa are complex mixtures, they sants du CP qui ont suscités un intérêt considérable pendant do not transfer intact to MSS. Their compositions in- plusieurs années. L’examen du transfert des humectants du clude compounds identical with or homologs of those tabac traité au CP des cigarettes indique que les humectants identified in tobacco. Thus, many individual licorice and exercent un effet de dilution significatif sur les composants cocoa components behave similarly to the same or simi- de la phase particulaire du CP, générés au cours du fumage lar tobacco components during the smoking process. d’une cigarette. Cette dilution diminue les effets évalué par Characteristic of licorice is glycyrrhizin, a potassium- plusieurs tests biologiques, e.g. la mutagénicité déterminée calcium salt of glycyrrhizic acid (6,7) which is a poly- au moyen du test Salmonella typhimurium d’Ames. [Beitr. hydric cyclohexane linked to a pentacyclic triterpenoid Tabakforsch. Int. 20 (2002) 279–99] comprising cyclohexane rings fused in the configura- tion of the polycyclic aromatic hydrocarbon (PAH) benzo[a]chrysene (Figure 1). The structural relation- INTRODUCTION ship between glycyrrhizic acid, benzo[a]chrysene, and a phenol elicited concern in some quarters that it would Materials added to a tobacco blend during its preparation generate PAHs and phenols during the smoking for inclusion in the final cigarette are usually classified as process (8). Licorice (3) is used to: “mellow and flavorants, casing materials, and humectants (2): smooth the smoke . [and] . as an adjunct to boost Flavorants: Flavorants used on cigarette tobacco the sweetness of tobacco products”. In 1981, previ- blends include menthol which may be used at a level as ously published composition studies on licorice were high as 0.8% (8 mg per gram) of the weight of the final reviewed by SCHUMACHER et al. (9)1. tobacco blend and/or a variety of materials which may number as many as 40 to 100 whose total weight generally does not exceed 0.2% (2 mg per gram) of the weight of the final tobacco blend. 1 Occasionally, menthol is used in a “nonmenthol” Numerous formal in-house reports (RDRs) and memoranda (RDMs, cigarette at a level so low that the amount transferred R&DMs, and CIMs) authored by RJRT R&D personnel are cited. Many have been published totally or in part in peer-reviewed journals and/or to MSS is so low that its characteristic taste and odor presented totally or in part at various scientific conferences (Tobacco are barely detectable to most consumers. Chemists’ Research Conferences, American Chemical Society Symposia Casing materials (3): These include sugars, licorice, on Tobacco and Smoke, etc.). Whether published, presented, or neither, and cocoa which have been used in the cigarette copies of all RJRT R&D reports cited are stored in various repositories such as the one in Minnesota. Their contents are available on the Internet tobacco blend, the so-called American tobacco blend, at www.rjrtdocs.com. The experimental procedures used, data collected, whose first prototype was the blend of flue-cured, and interpretations summarized here are described in detail in the reports cited. 280 Characteristic of cocoa is theobromine (3,7-dimethyl- does not exceed 0.2% (2 mg/g) of the tobacco blend xanthine), a homolog of caffeine (1,3,7-trimethylxan- weight, may comprise as many as 100 individual compo- thine), also present in cocoa but at a much lower level nents. In this case, the weight of each component averages than theobromine. Use of cocoa as a casing material in about 20 micrograms per gram (20 g/g) of tobacco filler. cigarette tobacco blends was discussed by HARLLEE Sugars, licorice, and cocoa are usually classified as casing and LEFFINGWELL (10). materials. Historically, these have been used as additives to Humectants: Chief among the humectants traditionally pipe tobaccos and cigarette tobaccos throughout the