Drying of Lippia sidoides Cham. in fixed-bed dryer

Abstract

This article was carried out to evaluate the necessary time for drying of leaves of Lippia sidoides Cham., with use of different temperatures of the drying air and of analyzing the effect of the time and temperature of drying in the production of essential oil. The drying processes come being intensely evaluated, even so little information exist on pos harvests procedures for medicinal plants. For the drying tests an experimental dryer of fixed bed of thin layer was used, with three trays. The medicinal plants were distributed evenly in the trays, in way obtaining a layer approximately of 0,10 m. The heating of the drying air was accomplished by means of a group of electric resistances. The drying tests were accomplished with temperature of the drying air for 40, 50, 60, 70 °C and temperature ambient and, as witness was used the fresh plant. The results demonstrated a negative correlation between temperature of the air and the time of drying. The percentage of essential oil, except for the sample drying to the temperature ambient, was not influenced by the increase in the temperature of the drying air. For the sample dry with air ambient, a reduction of 8% was verified in the extraction of essential oil in relation to the witness. In the treatments with temperature of the drying air for 40, 50, 60 and 70 °C had a decrease of 2% in the percent of essential oil in relation to the witness, not presenting statistic differences among the treatments and witness.