Judgment of Aroma Types of Middle and Upper Flue-cured Tobacco Leaves Based on Stepwise Discriminant Analysis

[Objective] The aim of this study was to establish mathematical models for judging the aroma types of middle and upper flue-cured tobacco leaves according to the contents and proportions of aroma compositions. [Method] The aroma types of tobacco leaves were judged based on stepwise discriminant analysis, using 63 C3F and 65 B2F tobacco leaf samples from 13 tobacco producing regions in 11 provinces of China （Huili in Sichuan, Baokang in Hubei, Wulong in Chongqing, Lu- oyang in Henan, Zhucheng in Shandong, Wuyi Mountain in Fujian, Malong in Yun- nan, Chuxiong in Yunnan, Bijie in Guizhou, Liuyang in Hunan, Suiyang in Guizhou, Kaiyuan in Liaoning, Nanxiong in Guangdong） as calibration samples, and 67 aroma components as indices. And the Fisher discriminant functions were verified using 21 C3F and 19 B2F tobacco leaf samples. [Result] Variation coefficients of the propor- tions were lower than that of contents of most aroma components in middle and upper leaves of the samples, indicating that the proportions were more stable than contents of aroma components. The proportions of benzyl alcohol, solanone, β-dam- ascone, neophytadiene, farnesylacetone A, palmitic acid, thunbergol, methyl linole- nate and cembratriene-diol were all over 1% in both middle and upper leaves, al- though the dominant aroma components of the same aroma type varied between middle and upper leaves. Moreover, 11, 18, 7 and 11 aroma components were re- spectively introduced into the Fisher discriminant functions established based on the contents and proportions of middle and upper flue-cured tobacco leaves, which ex- hibited accuracy rates of 91.7%, 100%, 91.7% and 91.7% in the judgments of other tobacco leaf samples. The results revealed that the components those determined aroma types in middle leaves were obviously more than in upper leaves. In middle leaves, the accuracy rates of aroma type judgment could be improved by using the proportions rather than the contents of aroma components as indices. However, the functions based on the proportions and the contents of aroma components in upper leaves gave close accuracy rates. [Conclusion] The results of the study will provide references for identifying aroma types of flue-cured tobacco leaves in future work.

Judgment of Aroma Types of Middle and Upper Flue-cured Tobacco Leaves Based on Proportions of Aroma Components

[Objective] This study aimed to establish mathematical models for judging the aroma types of flue-cured tobacco leaves from the upper and middle parts of plants. [Method] A total of 128 samples （63 C3F and 65 B2F） from 11 main tobac- co production provinces of China were selected as materials. Stepwise discriminant analysis was applied to samples with different aroma types and discriminant function was expressed with the proportions of 67 aroma components in total aroma con- stituents as the index. [Result] The ratio of most aroma components in clear and full aroma tobacco leaves was higher than that in middle aroma leaves. The ratios of 51, 43 and 40 aroma components of clear, middle and full aroma tobaccos were higher in upper leaves than that in middle leaves. Aroma components dominated certain aroma types differed between middle and upper leaves. The proportions of 18 and 11 aroma components in upper and middle leaves were led in the stepwise discriminant function respectively. Self-validation and cross-validation methods were applied to evaluate the original samples, and the accuracy rates reached 100% and 98.6% on middle leaves, 96.37% and 94.4% on upper leaves. The accuracy rates on some other samples reached 100% on middle leaves and 91.7% on upper leaves predicted with the model. [Conclusion] The ratio of aroma components as discriminant index could improve discriminant accuracy significantly in the middle and upper leaves. It could be used to analyze aroma types objectively, accurately and quickly.

减施化肥增施有机肥对烤烟产量和中部上等烟比例的影响

以云烟87为试验材料,设置5个处理(T1:100%无机氮;T2:85%无机氮+15%有机氮;T3:75%无机氮+25%有机氮;T4:65%无机氮+35%有机氮;T5:55%无机氮+45%有机氮),研究了减施化肥增施有机肥对烤烟生长发育、产量、品质和中部上等烟比例的影响。结果表明:增施有机肥有利于烟株提前现蕾,随着有机肥用量的增加和化肥用量的减少,烤烟腰叶长、腰叶宽、茎围、SPAD值均呈下降趋势;全部施用无机氮肥不利于中部烟叶的发育,造成中部烟比例和中部上等烟比例降低;T2处理的综合农艺性状优良,且5项经济指标和3项等级结构指标最高,但烟叶化学品质一般;T4处理的中部上等烟比例、上等烟比例、中部上等烟产值、均价表现较好,烟叶内在化学成分协调。

湖北十堰野人谷基地单元中上部上等烟叶质量特征及其稳定性分析

[目的]考察湖北十堰野人谷基地单元烟叶质量状况。[方法]以云烟87为研究对象,对2010—2015年野人谷基地单元连续6年中上部上等烟叶外观质量、感官评吸进行分析。[结果]中上部上等烟叶外观质量与感官评吸质量较好,需要进一步提高烟叶油分,增加烟叶余味;中上部上等烟叶外观质量和感官评吸质量均较为稳定,年际间质量变化不大;建议采取减氮密植技术,控制烟碱,降低淀粉,提升化学成分协调性,提高烟气的细腻柔和程度;适量增施有机肥,提高烟叶的油分和结构疏松度,增加烟叶香气质、香气量,减轻烟叶杂气,从而进一步提升烟叶的外观质量和感官评吸质量,保障湖北中烟对优质特色烟叶原料的需求。[结论]该研究可为基地单元烟叶的品质改善提供参考。