OPTIMIZATION OF HYDRODISTILLATION OF ESSENTIAL OIL FROM MENTHA SPICATA L. BY USING RESPONSE SURFACE METHODOLOGY

Abstract

This study was conducted to optimize the hydrodistillation process of Mentha spicata L. essential oil using the response surface methodology. The optimal values of operating parameters (independent variables) such as extraction time (100–240 min) and water volume to plant mass ratio (0.055–0.120) were investigated using a central composite design, which led to only 13 experiments. The response variables were selected the highest essential oil yield, and also the carvone ratio, which is the main component of the essential oil. The experimental data was fitted to a linear model for essential oil yield and a modified quadratic model for the carvone ratio. The hydrodistillation time and water volume to plant mass ratio have significant effects (p<0.05) on the both the essential oil yield and the carvone ratio. The optimal conditions were identified as 145.7 min of extraction time and a 0.105 ml/g water volume to plant mass ratio by the 3D response surface and the contour plots derived from the models. At these predicted conditions, the essential oil yield and carvone ratio were calculated to be 1.383% and 28.541%, respectively. The findings indicate that the response surface approach can be used successfully in the hydrodistillation of Mentha spicata L.