深色晾烟晾制过程中一些重要化学成分的变化

Changes of Some Important Chemical Composition of Dark Tobacco During Air curing

深色晾烟品种KY1 71在 2 2℃和 70 %相对湿度下晾制表明 ,晾制后 1～ 6周的叶肉和 2～ 6周的主脉水分迅速下降。晾制后 1～ 4周电导率迅速提高。晾制过程中叶肉和主脉中硝酸盐含量均没有显著变化。晾制 3周后主脉和叶肉中亚硝酸盐含量逐渐增加。打顶后及晾制初期叶肉中各烟草生物碱均增加 ,晾制 2～ 3周稍有下降 ,然后至晾制结束都没有变化 ,整个晾制过程主脉中各烟草生物碱含量均无变化。成熟采收的鲜烟叶及晾制 1周内的烟叶中各种亚硝胺含量为 0 ,晾制 1周后逐渐增加。晾制后 6周 4 (N 甲基 亚硝氨 ) 1 (3 吡啶基 ) 1 丁酮 (NNK)及总烟草特有的亚硝胺 (TSNA)、晾制后 5周N 亚硝基去甲基烟碱 (NNN)、晾制后 7周N 亚硝基假木贼碱 (NBA)和N 亚硝基新烟草碱 (NAT)含量达最高峰 。

Dark tobacco KY 171 was air cured at 22℃ and 70 %(RH) to determine the changes of some important chemical composition. Experiments indicated that moisture decreased rapidly both in lamina and midrib during 1～6 and 2～6 weeks of air curing. Electrical conductivity went up sharply during 1～4 weeks of air curing. Changes of nitrate did not occur both in lamina and in midrib. Nitrite increased gradually after 3 weeks of air curing both in lamina and midrib. Alkaloids increased after topping and early stage of curing and then decreased in lamina. Alkaloids in midrib did not change during the whole air curing. Green leaves and leaves with one week of air curing did not contain nitrosamines, but the nitrosamines in them increased gradually after one week of air curing 4 (methylnitrosamino) 1 (3 pyridy) 1 botanone(NNK), N nitrosonornicotine(NNN), N nitrosoanatabine(NAT )and N nitrosoanabasine(NAB)reached a peak after 6 weeks, 7 weeks and 5 weeks of air curing respectively, and the changes of nitrosamines were similar to nitrite.\;