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CORESTA Congress, Edinburgh, 2010, PT 02

Study on surface free energy and its components of different types of tobacco leaves

LIU Yang; HU Jun; ZHAO Mingyue; ZENG Shitong; LIU Shan
Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, Henan, China

In tobacco manufacture, wetting, which is an important behaviour at the solid-liquid interface, is a common physicochemical phenomenon present in between essences, casing sauce, humectants or water and tobacco surface. Surface free energy (SFE) and its polar and disperse fractions (non-polar fraction) are fundamental properties of solid surfaces, which is relative to anisotropy, roughness, wettability, adhesion and adsorption effects of the solid surface. To study the wettability and spreadability of tobacco leaves, SFE of three tobacco types (Burley, flue-cured, and Oriental) was obtained by measuring the contact angles between probe liquids with different surface tension and tobacco leaves. The aim of the study is to provide the basic data for tobacco technology, especially flavoring and casing. The results indicate that the SFE of three types is close, that is, SFE of Burley tobacco leaves is 25.21 mN/m, SFE of flue-cured tobacco leaves is 25.78 mN/m, and SFE of Oriental tobacco leaves is 27.15 mN/m. However, there is a distinct difference in the proportion of polar and disperse fractions. The disperse fraction of Oriental tobacco leaves is as high as 92.34%, while it is only 41.06% in flue-cured tobacco leaves and 65.53% in Burley tobacco leaves.