Influences of different curing methods on chemical compositions in different types of tobaccos

Whether quality can be improved and style characteristics of different types of tobaccos can be changed after being cured using different methods has not been clear yet. It is necessary to explore the influences of different curing methods on chemical compositions of different types of tobaccos. For this purpose, by taking flue-cured tobacco K326, burley tobacco Yunbai 3 and oriental tobacco Basma 14 as materials, the effects of air-curing, sun-curing and flue-curing methods on chemical compositions of these three types of tobaccos were investigated by taking the freeze-dried tobacco as the control group based on the equilibrium method of matter loss. The results show that compared with freeze-dried tobacco, (1) The air-cured, flue-cured and sun-cured were displayed in a descending order in terms of the dry matter loss and dry matter loss rate of K326, burley and oriental tobaccos thereby. (2) After performing air-cured, sun-cured and flue-cured, the starch contents in the oriental and flue-cured tobaccos greatly reduce while their contents of the total sugar and reducing sugar rose; the contents of starch and reducing sugar in the burley tobacco both decreased. (3) The contents of protein, total nitrogen and nicotine in the three types of air-cured, sun-cured and flue-cured tobaccos all significantly decreased. (4) The reduction amounts of the pigment content in the sun-dried burley and flue-cured tobaccos were the largest while that in the flue-cured oriental tobacco reaches the largest. (5) The total polyphenol contents in the three types of tobaccos all significantly reduced after being air-cured, sun-cured and flue-cured. The total polyphenol contents in the flue-cured and burley tobaccos were significantly larger than those in air-cured and sun-cured ones; the total polyphenol content in the sun-cured oriental tobacco was significantly larger than those in the groups treated with other curing methods. (6) The potassium (K) and chlorine (Cl) contents in the three types of tobaccos processed by the other curing methods were relatively stable. (7) The sensory evaluation scores of flue-cured tobaccos, burley tobacco and oriental tobacco were higher after flue-cured based on Yunnan sensory evaluation method. The study clarifies the transformation law of chemical compositions in different types of tobaccos under different curing methods. A type of tobaccos is not only limited to single curing method. It is feasible to combine multiple curing methods to enrich the style characteristics of tobaccos.