Effect of Lysimachia christinae Polysaccharide (LCP) on the Drying Kinetics Characteristics of Flue-cured Tobacco Lamina

Purpose We investigated the effectual rule of Lysimachia christinae polysaccharide (LCP) as a humectant on drying process of flue-cured tobacco lamina to understand the effect of the humectant on moisture retention of flue-cured tobacco lamina from a dynamic perspective.

Method The moisture content variation of Xuchang flue-cured tobacco lamina (X2F) through adding L. christinae polysaccharides under different drying temperature conditions was tested, the thin layer drying kinetics equation for the material moisture loss was determined, and the internal effective moisture diffusivities and activation energies were obtained.

Results LCPs could enhance the moisture holding capacity of flue-cured tobacco lamina and markedly reduce drying rate constant and effective moisture diffusivity; moreover, the effective moisture diffusivities of adding pure water and applying humectant materials were 1.286 8×10⁻¹²−1.671 8×10⁻¹² m²/s and 1.074 0×10⁻¹²−1.611 0×10⁻¹² m²/s, respectively, and the drying activation energies were 8.42 kJ/mol and 13.9 kJ/mol, respectively.

Conclusion LCPs could increase the moisture retention of flue-cured tobacco lamina materials. Two-term exponential model and Page model could better describe water desorption course for flue-cured tobacco lamina materials, and this work would provide ideas for understanding the effect of humectant on water desorption during the drying process of flue-cured tobacco laminas.