Study On Distribution Law Of Chemical Components In Leaves Of Flue - Cured Tobacco Leaves

Recent years, Good-quality tobacco leaves were demanded greatly by major tobacco companies with rapid developing of high-grade cidarette. Currently, how to subdivide and improve the value of a tobacco leave had been carried out a number of new cutting and roasting technology at home and abroad. Cutting methods were based on physical properties and appearances in different parts of tobacco leaves. In fact, the quality characterisitics of tobacco such as smoking scores and gas properties were determined by chemical composition. Quality of tobacco leaves was impacted by the chemical composition of tobacco leaves directly. Therefore, in the name of overall chemical composition of tobacco leaves, analysising vertical distribution of the main chemical components and examining intrinsic quality of different parts would be expected to provide new cutting method and theoretical supports for new cutting and roasting technology. In this paper, flue-cured tobacco leaves were cut into several parts in approximate equal areas. The main works were as follow:1. General chemical components were analysised to learn differences among cutting parts by flow analyzer. From tip to the leaf base most of chemical constituents had obvious infection points and than the rate of changes were accelerated markedly. From outer edge to the leaf stem most of chemical constituents had no infection points and the rate of changes were steady.2. The chemical indicators and their correlation analysis were done. Then eight kinds of chemical indicators were selected. Hierarchical cluster analysis (HCA) based on nine kinds of chemical indicators of different cutting parts were also completed. The results showed that part of about16percent tobacco length near the leaf base could be cut and then roasted independently. Therefore, Cutting method of new cutting and roasting technology could be determined from the view of conventional chemical composition.3. Regression equations were established between the main chemical indicators and different cutting positions of flue-cured tobacco leaves. The results showed that inflection point of every chemical composition could be drawn by the regression analysis and then cutting method was gotten by every chemical composition.4. Application of ion chromatography method for simultaneous determination of ammonium ions, potassium, calcium, magnesium ion longitudinal distribution in tobacco leaves was done. PH values of tobacco leaves were also measured in vertical direction.5. Partial least square (PLS) was utilized to build the calibration models after optimizing the spectral range and appropriate pretreatment. The results showed that distribution regularities of main chemical constituents in flue-cured tobacco leaves could be gotten fast by Near-infrared (NIR) quantitative models.6. NIR spectroscopy of different cutting parts was measured. PCA and HCA based on the near infrared spectroscopy of different cutting parts were also completed. The results showed that for Yuxi K326and Kunming Hongda flue-cured tobacco leaves, part of about9-25percent tobacco area (about15-30percent tobacco length) near the leaf base could be cut and then roasted independently. Results were basically the same with results based on conventional chemical composition.7. NIR microscopic imaging techniques combined with compare correlation image and chemi-maps image were applied to identity flue-cured tobacco leaves of different areas, grades and species. Results showed that, compare correlation image just could be applied to identity different grades and species. Chemi-maps image was applied to identity different areas, grades and species successfully and the sample differences were further enlarged.