The effects of different drying methods on weight loss rate, essential oil and chamazolene contents of chamomile (Matricaria recutita) flowers

Field experiment was carried out at the Ferdowsi University Research Field, Mashhad, Iran during 2007-2008, to determine the effect of different drying temperatures, microwave powers and natural method (shaded and sunny area) in Chamomile (Matricaria recutita L., Asteraceae) essential oil content, chamazolene content, drying time and drying rate. The experimental design was completely randomized block design having three temperatures: 50, 60 and 70 °C, six microwave powers: 100, 180, 300, 450, 600 and 900w and drying in shaded and sunny area, replicated thrice. The drying process was continued until the mass of the sample reduced to a moisture content of about 0.10 on a dry basis or 10% on a wet basis. The results indicate that different treatments of drying had a significant effect on the drying time and rate and essential oil and chamazolene content. The maximum essential oil content obtained at drying by the lowest temperatures and drying in shaded area. Whereas, higher drying temperatures of oven and microwave powers and drying in sunny area decreased the essential oil content. Maximum chamazolene content obtained at microwave drying (except 100w power) and natural method. Minimum chamazolene content was obtained at drying by oven.