Optimization And Empirical Study On Evaluation Methods Of Tobacco Leaf Quality

High-quality tobacco-leaf raw-materials is the foundation to support the development of China's tobacco, in particular for the development of Chinese style cigarette, and the accurate evaluation of tobacco-leaf quality will help to guide production of tobacco-leaf raw-materials, procurement and industrial applications. However, the tobacco-leaf quality evaluation is a complicated systematic project, there isn't systematic evaluation methodology of tobacco-leaf quality and which will impact on evaluating the tobacco-leaf quality scientifically and effectively, leading to blindness of tobacco-leaf quality evaluation. Therefore, the establishment of tobacco-leaf quality evaluation method system not only has theoretical significance, as well as has practical significance, for accurate analysis and understanding of the inherent law of tobacco-leaf quality, extracting succinctly the essence characteristics of tobacco-leaf quality, showing clearly the structure of tobacco-leaf quality system, and depicting scientifically the formation laws and variation characteristics of these tobacco-leaf quality system. In this study, a combination of the theory and methods of lots of disciplines such as tobacco cultivation, tobacco chemicals, tobacco processing, chemometrics, systems engineering, modern statistical analysis, data mining, and so on, constitute the methods system of tobacco-leaf quality assessment based on practice. The methods of tobacco-leaf quality assessment were optimized and proved by the flue-cured tobacco samples in Hunan and Yunnan. The main results are as follows:(1) According to the ladder-level of tobacco quality evaluation, from the methodological point of view, the tobacco-leaf quality evaluation methods system was established innovatively including exploratory, analytical, forecasting and comprehensive evaluation methods system. The basic ideas, main evaluation content and main evaluation methods of the evaluation levels were clarified. The established evaluation methods were optimized by empirical research, and the optimization evaluation methods can be applied in the exploration in the quality of tobacco leaves, analytical, forecasting and comprehensive evaluation of the exploratory, analytical, forecasting and comprehensive evaluation of tobacco-leaf quality, which can obtain good evaluation results. The tobacco-leaf quality evaluation methods system provides methods and theoretical basis for scientific evaluation of tobacco-leaf quality.(2) A new gray relational analysis method, that is, the grey relation signal-to-noise ratio method was put forward creatively, based on quality engineering principles. The impact on the gray relational degree from the uniformity and average of gray relational coefficient, is balanced in overall by the new method. of correlation of gray, and through application of proven The new method is effective. The effectiveness of the method was proved by the application of examples.(3) The R software and its programming language, which has a good strong statistical and mapping functions, was used comprehensively in the tobacco-leaf quality evaluation, and the good application effect was obtained. It has opened up a new means to evaluate systematically the tobacco-leaf quality by the latest modern statistics analytical methods and data mining technology.(4) The modern statistical methods and data mining technologies such as robust summaries, box-plot, dominance analysis, classification and regression trees, generalized additive model, multiple adaptive regression splines, two-step cluster analysis, robust design, robust MM linear regression, robust LTS linear regression, local (Loess) regression, and so on, were introduced to the tobacco-leaf quality assessment on the first time. The main results of cases study are as follows:①We can accurately describe the main characteristics of tobacco-leaf quality information, and will not ignore to fully mining the non-main information of tobacco-leaf quality, if we make comprehensive use of the robust summaries and box-plot in the exploratory evaluation of tobacco-leaf quality;②In the analytical evaluation of tobacco-leaf quality, we can accurately identify the relative importance based on linear about the physical and chemical characteristics effecting on the tobacco-leaf quality by dominance analysis. The relative importance based on both linear and nonlinear relationship about the physical and chemical characteristics can be accurately identified by classification and regression trees. The linear and nonlinear relationship between tobacco quality and physical or chemical characteristics can be clearly showed through the partial fitted plot of generalized additive model;③A better prediction effect was obtained in the forecasting evaluation of tobacco-leaf quality by multiple adaptive regression splines. This is a piecewise linear regression model based on less assumptions and is easily explained. It also can identify the key variable. So its application has good prospects in the forecasting evaluation of tobacco-leaf quality;④In the comprehensive evaluation of tobacco-leaf quality, by two-stage clustering method applicable to any type of variable, the optimal number of clustering can be automatically determined, and the importance of the evaluation indexes in clustering can be automatically given, which will help to confirm the important characteristics and variation of any classification types. So its application has good prospects in the comprehensive evaluation of tobacco-leaf quality;⑤The processing quality for tobacco leaves was evaluated comprehensively by robust design and the factors impacting on the quality of processing can be accurately identified as important factors, regulating factors, stable factors or secondary factors, which will help to improve and stabilize the quality of processing.(5) The all and the one relationship between physical and chemical characteristics and the flue-cured tobacco-leaf quality was parsed comprehensively and systematically. The main physical characteristics' effect on the appearance quality of flue-cured tobacco-leaf is greater than the impact of its main chemical compositions; The main chemical components' effect on the main smoke gas components and the smoking quality of flue-cured tobacco-leaf are greater than the impact of its main physical properties, and the effect of the appearance quality is the smallest; The effect factors of smoking quality and appearance quality of flue-cured tobacco-leaf are more complex than the ones of the main smoke gas composition of flue-cured tobacco-leaf; There is significant difference for the degree of physical and chemical properties impacting on tobacco-leaf quality in the different planting tobacco regions and the characteristics of tobacco-leaf quality can not be imitative.(6) The linear and nonlinear relationship between the single quality and physical and chemical characteristics of flue-cured tobacco-leaf in Hunan was parsed comprehensively and systematically. The results show that: the quality of tobacco leaves can be tokened by these key physical and chemical indexes such as total nitrogen, reducing sugar, nicotine, organic potassium, ratio of total nitrogen to nicotine, ratio of total sugar to nicotine, ratio of potassium to chlorin, single-leaf weight, leaf thickness, leaf width, leaf structure, body, degree of leaf smooth and tiny-green, etc.. There is significant the linear relationship between the majority of flavor components of tobacco and smoking quality of tobacco, but there is obvious non-linear relationship between some flavor components of tobacco and smoking quality of tobacco. There is clear positive correlation between the majority of flavor components of tobacco and smoking quality of tobacco, but there is significantly negative correlation between some flavor components of tobacco and smoking quality of tobacco.(7) The flue-cured tobacco smoke tar forecast model and the flue-cured tobacco aroma quality forecast model were established, and the good fitting and prediction effects were obtained by these forecast models. The comprehensive evaluation model of flue-cured tobacco chemical quality, the gray comprehensive evaluation model of the availability of flue-cured tobacco varieties, and the two-stage clustering evaluation model of the appearance quality of flue-cured tobacco, were established, and the good comprehensive evaluation of the effectts were obtained by these comprehensive evaluation models.