TSNA levels in the mainstream smoke of simplified blend prototypes
Different approaches have been reported in the literature to reduce the tobacco-specific nitrosamine (TSNA) levels in mainstream smoke (MSS). The reduction of TSNA in the raw tobacco is an approach that has received much attention in recent years. Different elements determine the level of TSNA in MSS: During combustion, part of the TSNA in the cigarette filler can transfer into smoke while another portion can undergo thermal degradation. Moreover, it is possible that TSNA can be pyrosynthesized and that concomitant synergetic effects between the blend components can also occur. Depending on their extent, the formation and degradation of nitrosamines during the combustion process might have an important impact on TSNA level in the smoke of blended cigarettes and might lead to MSS TSNA deliveries which would not parallel that of the blend components. A study was therefore undertaken to assess the feasibility of predicting the TSNA deliveries of blended products on the basis of the TSNA deliveries of the individual blend components. A highly simplified blend-model was chosen, including laminar Virginia, burley and Oriental tobaccos in fixed proportions. A set of one-, two- and three-component prototypes was prepared with various combinations of highand low-TSNA Virginia and burley tobacco. The pre-formed TSNA levels of the different blend components and the MSS delivery of the prototypes were determined. The TSNA deliveries of the blended prototypes were found to be in good agreement with the predictions based on both the MSS TSNA delivery and the pre-formed TSNA content of the individual blend components. This study showed that predicting MSS TSNA levels in the smoke of blended cigarettes could probably be achieved with adequate accuracy from the levels measured in the smoke of the laminar blend components. Strong indications were obtained that such predictions could be made from the preformed TSNA content of the raw tobacco. With respect to the reduction of TSNA in MSS, the reported results provided evidence that procuring tobaccos with very low levels of pre-formed TSNA would be an effective strategy to reduce the content of TSNA in MSS.