| Tobacco is a kind of leaf with profitable crops, its quality is extremely important, and the quality is ultimately determined by the chemical compositions of tobacco leaves. The chemical compositions of tobacco leaves in the appraisal have amounted to more than3000. Over the years, the merits of tobacco leaves quality are based on appearance and sensory evaluation to determine the absorption, but due to the differences in people’s habits and hobbies, unavoidably subjective evaluation of tobacco quality. Tobacco chemical compositions as a kind of measure of tobacco quality index have been brought to the attention of the related personnel. Chemical compositions in tobacco determine flue-cured tobacco appearance quality, internal quality, physical characteristics, flue gas characteristics and flue-cured tobacco aroma types, so it is necessary for studying chemical compositions of tobacco leaves systematically.In China, ecological environment is complex, and there is considerable difference of tobacco aroma style between different ecological regions. It provides a favorable condition for developing distinctive tobacco areas in China and forming characteristics of Chinese style cigarette style. Tlue-cured tobacco aroma types are currently one of the principal objects in the research and development flue-cured tobacco in our country. For a long time, China mainly depends on professionals to establish by sensory smoking tobacco scent style, which is greatly influenced by artificial factors, and undoubtedly leads to separate results for one sample. In China, aroma types of flue-cured tobacco (FCT) were divided into light, medium, and heavy. However, evaluation of FCT aroma types using chemical compositions in a quantitative way at national scale is limited. This study applied discriminant analysis to identify characteristics and distributions of FCT aroma types. A total of222samples with grade of C3F representing main FCT production counties were collected. Multi-year average chemical compositions of the samples were analyzed. The main research contents and results were as follows:(1)It can be concluded by comparing chemical compositions of three varieties of tobacco leaves:Protein, Total volatile acid, Ratio of potassium to chlorine, Potassium, Chlorine, Nitrate of K326are relatively higher than other varieties of tobacco; Total plant alkaloid, Total nitrogen, Total volatile alkali, Ash content, Alkalinity of water-soluble ash content of Yunyan85are relatively higher than other varieties of tobacco; Water-soluble total sugar, Reducing sugar, Ratio of nitrogen to nicotine, Ratio of sugar to nicotine, Petroleum ether extracts, pH, Sulfate of Yunyan87are relatively higher than other varieties of tobacco.(2) It can be concluded by comparing chemical compositions of three growth sites of tobacco leaves:Total plant alkaloid, Protein, Total nitrogen, Chlorine, Petroleum ether extracts, Sulfate of B2F are relatively higher than other two growth sites; Water-soluble total sugar, Reducing sugar, Total volatile acid, Total volatile alkali of C2F are relatively higher than other two growth sites; Ratio of nitrogen to nicotine, Ratio of sugar to nicotine, Ratio of potassium to chlorine, Potassium, pH, Nitrate, Ash content, Alkalinity of water-soluble ash content of X2F are relatively higher than other two growth sites.(3) By selecting samples of C3F from Henan Province, Guizhou Province, Yunnan Province, and comparing changes of main chemical compositions between2003and2007, we could get the following conclusion:There were some differences between main chemical compositions of tobacco leaves in different years.(4) By selecting samples of C3F and producing spatial distribution maps of main chemical compositions of tobacco leaves, we could get the following conclusion:Content of chemical compositions, quality of tobacco leaves, aromas types differed in different ecological environment in China.(5) In China, aroma types of flue-cured tobacco (FCT) were divided into light, medium, and heavy. However, evaluation of FCT aroma types using chemical compositions in a quantitative way at national scale is limited. This study applied discriminant analysis to identify characteristics and distributions of FCT aroma types. A total of222samples with grade of C3F representing main FCT production counties were collected. Multi-year average chemical compositions of the samples were analyzed. The accuracy of strong aroma style was88.9%, the accuracy of intermediate aroma style was90.0%, and the accuracy of clear aroma style was100%, so the average discriminant accuracy was92.6%.39samples were determined as strong aroma style, and105samples as intermediate aroma style,51samples as clear aroma style among all195testing samples. Sixteen of the chemical compositions showed significant difference between the aroma types (p<0.05). Regional distribution of FCT samples indicated that ecological factors had significant impact on FCT aroma. Areas with higher elevation, annual mean temperature, and rainfall had potential for producing light aroma FCT. The results and methodologies are expected to provide valuable information for regional planning and decision making for production of high-quality tobacco. |
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