EFFECT OF DRYING AIR TEMPERATURE UPON THE ESSENTIAL OIL CONTENT FROM GUACO.

ABSTRACT: This study aimed to evaluate the influence of drying air temperature on the content of essential oil extracted from guaco (Mikania glomerata Sprengel). The drying tests were performed in an experimental fixed-bed dryer, which contains 4 perforated trays with upward air flow. The treatments consisted of five temperatures for the drying air (environmental air and the air heated at 40, 55, 70 and 85 ºC), with three repetition, using 850 g of fresh guaco leaves on the top tray. The guaco leaves were dried until reaching a final water content of approximately 10 % w.b. The drying air velocity was 0.5 m.s-1 and was measured by an anemometer. The drying air temperature control was made using an automatic controller with a variation of ± 2 ºC. The essential oil extraction was performed by using Clevenger device. The results of the oil content showed that the drying air temperatures of 55 and 85 ºC did not statistically influence the amount of essential oil extracted