Effects of Curing and Fertilization on Nitrosamine Formation in Bright and Burley Tobacco

A bright and a Burley tobacco were grown at four fertilization rates and each tobacco was then both flue-cured and air-cured. Levels of alkaloids and nitrosamines were found to increase with increasing fertilization levels. Levels of alkaloids, N-nitrosonornicotine (NNN), and other tobacco-specific nitrosamines (TSNA) were consistently higher in the Burley tobacco than in the bright tobacco, regardless of curing method. In comparing the effects of curing, it was found that NNN and total TSNA levels were higher in the midrib than in the lamina of the air-cured samples, while just the opposite was found for the flue-cured samples. Flue-curing bright tobacco produced three times the level of TSNA vs air-curing the same tobacco. On the other hand, flue-curing Burley tobacco reduced the alkaloids, but greatly increased the TSNA in the lamina. As midribs from the air-cured Burley leaves had three times the TSNA concentration of the lamina, the use of air-cured midribs in tobacco products should be avoided. It was concluded that lower fertilization levels and careful manipulations of curing parameters could lower nitrosamine levels in cured tobacco