Study On Extraction Of Flavor Components In Tobacco Stem

Tobacco production and consumption in China are the highest over the world,million tons of tobacco stem are produced during the tobacco production process every year and only 40% of them are utilized effectively,most of them are treated as waste disposal,thus cause the waste of biomass resources.The chemical composition of tobacco stem are similar to tobacco leaf,which contains varieties of flavor components,it can be used to prepare the essential oil with the tobacco flavor.In this article ultrasonic assisted extraction method and supercritical CO₂ extraction method were used to extract the flavor components in tobacco stem and prepare tobacco extractum,then molecular distillation was used to refine the extractum and obtain the essential oil.The composition and content of the tobacco extracts can be analysed by GC-MS,the results are as follows:1.The optimal conditions of ultrasonic assisted extraction method were: using ethyl acetate as extraction solvent,the liquid-solid ratio of ethyl acetate and tobacco stem 12 m L/g,ultrasonic power 80 W,ultrasonic temperature 60?,ultrasonic time 60 min,the yield of tobacco stem extract was 2.74%±0.05%.The results of GC-MS showed that the extractum by this method contained several flavor components in tobacco,such as solanone,neophytadiene,geranylacetone,dihydro-beta-ionone and so on,there were also a certain amount of alkane compounds in the extracts at the same time.2.The optimal conditions of supercritical CO₂ extraction method were:extraction temperature 60?,extraction pressure 32 MPa,CO₂ flow rate 24 L/h,extraction time 2.5 h,ethanol solution was adopted as the entrainer,its volume fraction was 85% and its mass fraction in tobacco stem was 20%,the yield of tobacco stem extract was 1.70%±0.03%.The results of GC-MS show that the extracts by this method contained several flavor components in tobacco,such as megastigmatrienone,damascenone,geranylacetone,neophytadiene,cembrenediol and so on.3.Using response surface method to optimize the molecular distillation process,regard essential oil yield of tobacco stem as response value and established quadratic regression equation,the optimal conditions of molecular distillation were: distillation temperature 140?,wiper rotational speed 246 r/min,condenser temperature 39?,the essential oil yield under this condition was 10.46%±0.05%.The results of GC-MS showed that the content of cembrenediol,neophytadiene,megastigmatrienone,damascenone and other flavor components in essential oil increased 1-3 times after molecular distillation,the content of macromolecular reduced significantly,it indicated that the small flavor components can be enriched by molecular distillation,thus making the fragrance of essential oil rich and nice.4.The cracking gas composition of tobacco slice after flavoring increased significantly.The pyrolysis products of tobacco slice by ultrasonic assisted extraction mainly consisted of benzene and naphthalene compounds,which were the characteristics pyrolysis products of beta-ionone and other carbonyl compounds.The pyrolysis products of tobacco slice by supercritical CO₂ extraction mainly consisted of palmitic acid and linolenic acid and other senior fatty acid,neophytadiene was also existed in the pyrolysis gas.Megastigmatrienone,damascenone and other important flavor components were detected in the pyrolysis products of tobacco slice by molecular distillation,thus further revealed that the small flavor components can be enriched by this method.