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CORESTA Congress, Kyoto, 2004, AP 04

Potential changes of TSNA composition in stored tobacco powder: consequences for sample preparation and ground tobacco storage

DE ROTON C.; GIRARD C.; JACQUET L.; POISSON C.
Altadis - Institut du Tabac, Bergerac, France

A study carried out in 2003-2004 at the "Institut du Tabac de Bergerac" aimed at better defining how to dry moist samples of cured tobacco and how to keep the powder for TSNA analyses.

Cured whole leaves of a burley variety were fine cut, homogeneized and humidified up to 34%. Control samples of cut rag were immediately freeze dried and kept at -70 °C until analysis. Three methods of sample drying (ambient temperature, force air drying at 30 °C and liquid N followed with force air drying at 30 °C) were combined with three temperatures of storage of the powder in closed jars (ambient, refrigerator ~ +6 °C, freezer ~ -18 °C). Samples of ground tobacco were analysed immediately, and after 1, 3 and 6 months.

All the 3 methods of drying increased slightly the TSNA conc., as compared with immediate freeze drying.

In the powder stored at ambient temperature, the TSNA conc. increased dramatically, rising from 1,3-1,4 µg/g at the beginning, to 8,1-9,5 µg/g after 6 months.

In the powder stored in the refrigerator and in the freezer, the TSNA conc. were stable or increased only very slightly, up to 1,9-2,1 µg/g and 1,5-1,7 µg/g resp.

In the course of storage, the composition in individual nitrosamines was affected by the temperature of storage: NNK increased, all the more since the temperature was low, NNN increased slightly with temperature and NAT decreased at low temperature.

Over the period of storage, nitrite conc., which were initially low (1,5-2,5 µg/g), decreased during the first 3 months in the powder kept at ambient temperature, slightly at fridge temperature, and did not change at freezer temperature.

The results suggest that, at ambient temperature, even low nitrite conc. may form significant amounts of TSNAs in ground tobacco, with time.

It is concluded that:

  • moist samples of cut rag from cured tobacco should be either freeze dried or force air-dried at 30 °C;
  • ground tobacco powder should not be kept for a long time;
  • if storage is necessary, tobacco powder should be kept at low temperature.