16个雪茄烟品种的烟碱转化率及与发酵后烟叶TSNAs含量的关系

  目的  明确不同雪茄烟品种烟碱转化率差异及与烟草特有亚硝胺(TSNAs)含量的关系。  方法  对16个雪茄烟品种的中部叶生物碱、硝酸盐和TSNAs含量进行了测定，并分析了其相关关系。  结果  1) 不同品种雪茄烟叶均存在烟碱向降烟碱的转化问题，参试的16个品种烟碱含量变化范围为1.14%~5.42%，平均为3.02%，降烟碱含量的变化范围为0.11%~1.47%，平均值0.40%，烟碱转化率范围为5.03%~53.12%，平均值为12.66%，品种间烟碱转化率的变异系数高达101.01%。2)茄衣品种的降烟碱含量和烟碱转化率平均值显著高于茄芯品种。3)不同雪茄烟品种烟叶中的TSNAs含量和组成具有显著差异，总TSNAs含量的变化范围为181.74 ng/g~7759.1 ng/g，平均为3010.98 ng/g，以NNN含量最高，且变异性最大，其平均值为1616.59 ng/g，变异系数为97.28%。4)相关分析结果显示，参试的16个品种的雪茄烟叶中降烟碱含量、烟碱转化率都与NNN和TSNAs含量呈极显著的正相关关系，NNN与降烟碱含量的相关系数为0.802。  结论  烟碱转化导致降烟碱含量增高是造成雪茄烟叶中NNN含量和总TSNAs含量增加的主要原因之一。 

Nicotine conversion rate of 16 cigar varieties and its relationship with TSNAs content in fermented tobacco leaves

  Objective  This study aims to investigate the difference in nicotine conversion rate among different cigar varieties as well as the relationship between nicotine conversion rate and TSNAs content in cigar tobacco.  Methods  The alkaloids, nitrate and TSNAs contents in the middle leaves of 16 cigar varieties were analyzed.  Results  1) All cigar varieties had the problem of nicotine to nornicotine conversion at different degrees. The nicotine contents of 16 cigar varieties were in the range of 1.14% to 5.42%, averaging at 3.02%; and nornicotine contents changed in the range from 0.11% to 1.47%, averaging at 0.40%. The nicotine conversion rate ranged from 5.03% to 53.12%, with the average value of 12.66%, and the variation coefficient of nicotine conversion among varieties was as high as 101.01%. 2) The average nornicotine content and nicotine conversion rate of cigar wrapper varieties were significantly higher than those of cigar filler varieties. 3) The content and proportion of TSNAs in tobacco leaves of different cigar tobacco varieties were significantly different. The variation range of total TSNAs content was 181.74~7759.1 ng/g, with an average of 3010.98 ng/g. The content of NNN was the highest, with the average value of 1616.59 ng/g, and the variability was also the highest, with the coefficient of variation as high as 97.28%. 4)Correlation analysis showed that there was a significant positive correlation between nornicotine content and NNN and TSNAs content in 16 cigar tobacco varieties, with the correlation coefficient between NNN and nornicotine content reaching 0.802.  Conclusion  The high level of nornicotine content resulted from nicotine conversion is one of the main cause for the increased formation and accumulation of NNN and total TSNAs in cigar tobacco leaves.