Tobacco Glycosides Compounds

Glycoside compounds in tobacco, with large molecular weight, high boiling point and little even no aroma, are secondary metabolites formed during the growth of tobacco plants. However, glycoside compounds are able to release aroma through heating and thermal cracking during smoking, which contributes much in absorbing aroma of tobacco. But the systematical research of glycoside compounds existence form and variety is rare. Glycosides substances as secondary metabolites of tobacco are of great variety, so that it is difficult to obtain standard sample. In this study, by using combined method of organic solvent extraction, HPLC (High Performance Liquid Chromatography) and column chromatography, glycoside compounds were isolated from middle flue-cured tobacco leaf, identified structure. The pyrolysis products and mechanism of glycoside compounds was researched by using thermal analysis technique with the isolated glycoside compounds as glycoside samples. Meanwhile, the feasibility of isolated glycoside compounds as thermal stability spice adding to the cigarettes was discussed. The research focuses on and results are as follows:1 Preparation and characterization of glycoside compoundsBy using combined method of organic solvent extraction, column chromatography and HPLC (DAD detector), middle flue-cured tobacco leaf were isolated. Thin layer chromatography (TLC) was used to detect concentration of reactant and resultant, C-18 reversed-phase (RP) column chromatography was used to prepare lots of samples under gradient elution condition, RP-HPLC was applied to subdivide and purify the sample. Then EIS-MS,1HNMR,13CNMR were applied to the characterization of isolated glycosides compounds. Isolated glycosides compounds includes:scopolin,2"-O-α-L-Rhamnopyranosyl,3-oxo-α-ionol-β-D-glucopyranoside, 7,8-dihyd-3-oxo-α-ionol-β-D-glucopyranoside, Quercetin 3-β-D-rutinoside, Quercetin 3-O-α-L-rhamnosyl-β-D-pyranoside,8-O-β-D-glucopyranoside.2 Release of glycoside aroma components in tobacco Pre-treat different parts KB2F (up), KC2F (middle), KX2F (below) of the same tobacco by solvent extraction. With GC-MS, detect composition and content of glycoside aroma precursors in different tobacco parts. The results showed:the total classes and content of the Glycosides aroma precursors in middle leaves is higher than the upper leaves and lower tobacco.Pyrolytic volatile substances of isolated glycoside compounds were analysed qualitatively and quantitatively using Py-GC-MS. On this basis, with review of literatures, the pyrolysis product formation mechanism of glycoside compounds was discussed. The main pyrolysis products were megastigmatrienones,3-oxo-.alpha.-ionol and 4-(3-hydroxybutyl)-3,5,5-trimethyl-2-Cyclohexen-1-one.3 Thermal analysis for flue gas composition and glycoside compounds splitting mechanismBy using STA-IR-GC-MS, two tobacco weight-losses were monitored online comprehensively, while its pyrolysis products were analysed online and qualitatively.By using STA-IR-GC-MS, under programmed temperature condition, nitrogen atmosphere, the variation of glycoside compounds quality and temperature was researched. The results showed:the main pyrolysis products was researched. of the Glycosides at different thermal decomposition temperature. With this method, glycoside compounds combustion process was monitored online comprehensively, while its pyrolysis products were analysed online and qualitatively4 Application of glycoside compounds in the flavor of cigarettesAdd 3-oxo-α-violet alcohol-β-D-glucopyranoside and quercetin 3-β-D-rutinoside to cigarettes respectively, the smoking results shows that,3-oxo-α-violet alcohol-β-D-glucopyranoside display a better flavor effective.