烟草类型及贮藏环境对烟叶氮氧化物形成的影响

为明确烟草类型及贮藏环境对烟叶氮氧化物形成的影响，利用真空干燥器设置了密闭的环境，检测和分析了不同烟叶类型、贮藏温度和时间及含水率条件下环境中气态NOx（Nitrogen oxides）含量的差异。结果表明:贮藏过程中烟叶形成的氮氧化物以NO为主。相同的贮藏条件下，白肋烟产生的NOx浓度高出烤烟约9倍。当贮藏温度从10℃提高到50℃，处理48 h后白肋烟样品产生的NO和NO₂浓度逐渐升高。白肋烟经过50℃贮藏2 h后，即可检测出NOx，且随着处理时间的延长NOx的浓度不断增加。相同贮藏温度下，含水率高于18%的烟叶产生的NO和NOx浓度与含水率11.03%和12.29%相比显著降低；烟叶隔离加入活性炭后，烟叶贮藏环境中的NOx浓度显著降低。研究表明，贮藏环境控制可以抑制和减少烟叶本身氮氧化物的产生，从而减少贮藏过程中烟叶TSNA的形成。 

Effect of storage environment on nitrogen oxides formation in leaves of tobacco of different types

In order to study the effect of storage environment on nitrogen oxides (NOx) formation from tobacco leaves, content of NOx in airtight environment set up by vacuum desiccator was measured for different tobacco types, storage temperatures and duration at different moisture contents. Results showed that NO accounted for more than 90% of the NOx produced from tobacco leaves during storage. NOx concentration from burley tobacco leaves was almost 9 times higher than that from flue-cured tobacco under same storage conditions. As storage temperature increased from 10℃ to 50℃, the concentration of NO and NO₂ produced from burley tobacco increased gradually 48h after treatment. NOx could be produced in burley tobacco samples in a short period of time (2h) under 50℃, and increased with increase of storage time. Under the same storage temperature, NO and NOx concentrations of tobacco leaves with moisture content higher than 18% were significantly lower than samples with moisture content of 11.03% and 12.29%. Presence of activated carbon in storage containers effectively reduced the concentration of NOx. It was concluded that proper control of storage environment is an effective way to reduce TSNA formation in tobacco leaves by inhibiting and reducing production of NOx from tobacco itself.