Development of a New Model for Mass Transfer Kinetics of Petals of Echium amoenum Fisch & Mey under Fluidized Bed Conditions

Abstract

A new semi-theoretical thin-layer model of the fluidized bed drying of Echium amoenum Fisch. & C.A. Mey. petals has been developed. Experiments were conducted under different conditions: temperatures of 40, 50 and 60 °C, and air velocities of 0.5, 0.75 and 1.0 m/s, until the moisture content decreased to 0.04.-0.06 kg of water per kg of dry matter. Drying processes in the fluidized bed were completed in between 55 and 465 min, with minimum drying time required at the maximum temperature of 60 °C and air velocity of 1 m/s. The comparison of the new model developed here with sixteen previously published theoretical, semi-empirical or empirical thin-layer drying equations shows that using the new model the highest coefficient of correlation, the lowest reduced chi-square and root mean square error were obtained. The highest retention of total phenolic compounds in E. amoenum petals was achieved when drying at 60 °C and 1.0 m/s.