Extraction of essential oil from rosemary leaves: optimization by response surface methodology and mathematical modeling.

The extraction of essential oil from rosemary leaves is of interest for industrial applications as it is considered as a potential therapeutic agent to cure many diseases. Thus, the present study aims to optimize the extraction conditions. The effects of processing parameters of a steam distillation process on the extraction yield of rosemary essential oil are investigated using response surface methodology. A central composite design is applied to evaluate three independent variables such as extraction temperature (103-118 °C), time (2-6 h) and feed mass (200-600 g) on the extraction of rosemary essential oil. The maximum yield under the optimum condition is 2.8 % (by wt.). Further, deviations between the experimental and predicted values are less, and they are statistically insignificant. Furthermore, the predicted data from the mathematical model that involves convection-diffusion processes show a good agreement with the experimental data of the extraction of rosemary essential oil by steam distillation....