Optimization of Superheated Water Extraction of Essential Oils from Cinnamon Bark Using Response Surface Methodology

Response surface methodology (RSM) was applied to evaluate the extraction conditions of Cinnamomum zeylanicum Blume using superheated water extraction (SWE) followed by solid phase extraction (SPE). E-cinnamaldehyde as the main oxygenated component of C. zeylanicum essential oil was selected to be the representative of the whole desirable essential oil. Influence of operating conditions such as temperatures from 100 to 160 degrees C, flow rates from 1.0 to 4.0 ml/min, and mean particle sizes from 0.250 to 1.000 mm on essential oil yield and extract concentration was investigated. The optimal extraction condition was predicted to be at 138 degrees C, flow rate of 1 ml/min and mean particle sizes of 1.000 mm. Maximum yield and extract concentration from the mathematical model and the experiments were 2.21 % and 2.69 %, and 0.280 and 0.318 mg/ml, respectively. The essential oil composition of C. zeylanicum using SWE followed by SPE was compared with hydrodistillation method. The amount of desirable E-cinnamaldehyde obtained using SWE was the same as hydrodistillation, but the levels of non-oxygenated sesquiterpenes were lower.