不同采收期雪茄烟叶化学成分聚类分析及在分级中的应用

为明确不同采收时期雪茄烟叶化学成分含量的差异及在烟叶分级中的作用，以巴西3号雪茄烟叶品种为材料，对不同采收时期的烟叶化学成分进行分析。结果表明，雪茄烟叶化学成分中总植物碱和钾含量(质量分数)与采收时期的相关性达到极显著水平，相关系数分别为0.872**和-0.915**。用总植物碱和钾含量作为聚类因子进行聚类分析，巴西3号不同采收时期的烟叶样品聚类点群数为5个时，组别间的聚类质心均匀且聚类点群间的距离明显，聚类相似性达到95.1%，说明总植物碱和钾含量能较好地反映不同采收时期雪茄烟叶品质间的差异，可作为分级的重要参考指标。雪茄烟叶聚类分组结果显示，烟叶中总植物碱和钾含量与烟叶外观品质中身份指标的关系密切。 

Cluster analysis of chemical components in cigar tobacco harvested at different time and its application in leaf grading

In order to clarify the different contents of chemical components in cigar tobacco leaves harvested at different time and their roles in tobacco leaf grading, the chemical components in cigar tobacco leaves of cv. Brazil 3 were analyzed. The results showed that the correlation of the mass fractions of total alkaloid and potassium in the leaves with harvest time were extremely significant with the correlation coefficients of 0.872** and -0.915** respectively. Cluster analysis was carried out by taking the contents of total alkaloids and potassium as cluster factors. When the number of clusters was 5, the cluster centroids between groups of cigar tobacco leaves of cv. Brazil 3 harvested at different time were uniform and their distances were obvious with the similarity up to 95.1%, which indicated that the contents of total alkaloids and potassium could reflect the quality differences among the leaves harvested at different time and could be used as important reference indexes in leaf grading. The result of cluster grouping showed that the appearance quality index, body, of cigar tobacco leaves closely related to the contents of total alkaloids and potassium in tobacco leaves.