The non-isothermal behavior of the stem biomass of Nicotiana tabacum was investigated in depth using thermogravimetric analyzer (TGA). The thermal behavior of tobacco stems showed different patterns depending oil decomposition conditions as well as tobacco varieties. The higher contents of the volatile components and simple sugar in the bright stem resulted in the greater thermal decomposing in the temperature range ca. 120-250 degrees C. The structural difference in hemicellulose and cellulose depending on tobacco varieties could be detected by the temperature difference in the derivative TG result. The thermal analysis of the freeze-dried soluble obtained from hot water extraction of tobacco stem demonstrated that the distinct weight loss of the bright stem at around 570 degrees C was due to oxidation of the residual char originated from the soluble fraction, Such as simple sugar. (C) 2008 Elsevier B.V. All rights reserved.