in blends are usually 15 to 45 percent. Maryland tobacco con- 

 tributes filling power to the cigarette and is believed to im- 

 prove generally the smoke flavor; this type is added in small 

 amounts, 1 to 5 percent, to domestic blends. Turkish tobacco 

 imparts aroma, mildness, and a distinctive, pleasant taste to 

 the smoke; this tobacco is used in amounts ranging from about 

 5 to 15 percent in blends. 



Although these generalized contributions of the tobacco 

 types are known, little information is available on the specific 

 chemical components that are responsible for the flavor im- 

 parted to smoke by the types. In fact, fundamental chemical 

 differences in the smoke of different tobacco types have been 

 investigated only recently. Although of significant value, such 

 chemical differences may not be related to observed differences 

 in smoke flavor since the chemical components in question may 

 play no role in the overall smoke flavor. The present report 

 describes an attempt to relate previous findings on Turkish to- 

 bacco smoke composition to the organoleptic properties of 

 smoke from blended cigarettes containing such tobacco. 



RESULTS AND DISCUSSION 



Technical background 



As a result of basic studies on the composition of tobacco 

 leaf and smoke conducted recently at this Division, certain 

 fundamental differences were found in the chemical composi- 

 tion of the various tobacco types and the smoke produced from 

 such types. Included in this work were comparative studies of 

 the steam-volatile neutrals of leaf (1) and cigarette smoke (2) 

 and steam-volatile acids of leaf (4, 5) and smoke (7). Among 

 the significant findings was the observation that Turkish to- 

 bacco leaf and cigarette smoke were strikingly different from 

 other cigarette tobacco types in the amounts and proportions 

 of ]3-methylvaleric and isovaleric acids (4, 5, 6, 7). Table 1 

 presents pertinent data on this point in the case of cigarette 

 smoke. Also, it was shown that the addition of Turkish tobac- 

 co to blends of bright, burley, and Maryland tobaccos resulted 

 in an increase in the amounts of the steam-volatile acids found 

 in the smoke compared to the levels expected from an additive 

 contribution of each tobacco (7). For isovaleric and /3-methyl- 

 valeric acids, increases of 48 to 62 percent greater than ex- 

 pected were obtained. 



These unusual properties of Turkish tobacco prompted fur- 

 ther investigations of the influence of isovaleric and j3-methyl- 

 valeric acids on the flavor of cigarette smoke which are de- 

 scribed below. 



