Smoke curing aroma

Being interested here in the volatile components of coffee aroma, we shall arbitrarily limit the list of the aromatic hydrocarbons to tricyclic structures. The higher fused polycyclic hydrocarbons (fluoranthene [206-44-0], pyrene [129-00-0], chrysene [218-01-9], benz[ ]anthracene (1,2-benzanthracene) [56-55-3], benz[< ]acephenanthrylene (3,4-benzofluoranthene) [205-99-2], benzo[ ]pyrene (3,4-benzopyrene, 3,4-BP) [50-32-8], benzo[e]pyrene (1,2-benzopyrene) [192-97-2], perylene [198-55-0], benzo[g,/i,/]perylene (1,12-benzopyrene) [191-24-2], and dibenz[ ,//]anthracene (1,2,5,6-dibenzanthracene) [53-70-3]) cannot be considered as a part of the aroma. However, as some of these, specially benzo[o pyrene, are known for carcinogenic properties, they have been particularly analyzed in food subject to roasting or smoke-curing. 

The effect of carotenoids upon smoke flavor and aroma has resulted in new endeavors in research to increase levels of carotenoid derivatives. Plant breeders, attempting to improve tobacco quality, have developed cultivars with higher carotenoid levels. Beatson and Wernsman increased carotenoid content 40% by back-crossing and selection in only five generations. Statistical analyses of these data showed positive correlations between carotenoids and nicotine in these flue-cured tobaccos (r=.8l) (12). 

With regard to tobacco components, Lloyd et al. (2389) identified 275 previously unidentified components of additive-free flue-cured tobacco, 132 new to all additive-free tobacco types. Many of these compounds were highly polar and considered significant contributors to MSS flavor and aroma. Similar detailed studies were conducted on the composition of hurley tobacco by Roberts and Rohde (3219), Oriental tobacco by Schumacher and Vestal (3561), and Maryland tobacco by Schumacher (3550). Years later, it became apparent that many of the highly polar components of tobacco and tobacco smoke were identical with similar to many of the components used in the flavor formulations, that is, the top dressing, added to a specific tobacco blend to impart its unique smoking characteristics (1053). Randomly selected publications on the identification of many additive-free tobacco and/or tobacco smoke components are listed in Table II.A-2. 

Pyridines contribnte to the characteristic tobacco flavor of smoke. Fnjimori (1248) identifled twenty-six pyridines as components of tobacco aroma. Leffingwell et al. have tabnlated the flavor and aroma characteristics of many pyridines (2341). Pyridines as a class of componnds enhance tobacco flavor, add bnrley flavor, or can add fine-cured flavor. Pyridines are responsible for that characteristic note in smoke that identifles the smoke as that from tobacco (1587a). Hoffmann and Wynder (1803) have made the comment that pyridines are responsible for the off-taste and irritancy of the smoke from large cigars and that pyridines rednce the inhal-ability of cigar smoke. 

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