Kinetics coefficients of solid-liquid extraction of resinoid from tobacco leaves

摘要

Cured tobacco leaves(Nicotiana tabacum L.)from three commercial types-flue cured Virginia,Burley and Oriental,were processed by extraction to obtain the concentrated aromatic product resinoid,which is used in cosmetics and other areas.The objective of the study was to characterize the kinetics of the process of tobacco resinoid extraction by two basic indices-the coefficient of internal molecular diffusion(D_(int))and the coefficient of mass transfer(β).For that purpose,extraction was carried out at different temperatures(in the range between 20°C and 70°C),and the process was divided into a series of consecutive 10-minute intervals,for which the respective values of the kinetics coefficients were calculated.Based on the established variations of D_(int),by tobacco type,time and temperature,the respective regression models were derived.The coefficients of mass transfer,as well as the kinetic indices of the extraction process-the Biot diffusion number(Bi)and the Fourier diffusion number(Fo),were calculated for the three tobacco types.Data from the applied calculation procedures are presented in the study.