Optimization of the extraction by steam extraction of rosemary essential oil (Rosmarinus officinalis) using sequential designs

The objective of the present study was to evaluate the effect of charge density, steam flow and condition of the raw material in the yield of the essential oil of Rosemary (Rosmarinus officinalis) extracted by steam drag. The experimental methodology consists in working in the first stage with two steam flows (4 kg/h and 6 kg/h) related to two states of raw material (dry and fresh) and two densities of load (1 kg and 3 kg). The essential oil of rosemary (Rosmarinus officinalis) was extracted from the leaves of Romero using the method of discontinuous distillation by stream of water vapor. All these factors were worked with the Taguchi methodology with an orthogonal arrangement L4 (23) at 3 levels each. In the second optimization stage, the MSR was used with a rotatable central composite design (DCCR) which was used to evaluate the effect of the load density and vapor flow variables. The DCCR consisted of a complete factorial planning 22, 4 axial points and 3 repetitions in the central point totaling 11 trials. A second-degree polynomial model was used to predict the response. The highest yield of rosemary essential oil is obtained when the raw material is in the dry condition, a loading density of 1 kg and a steam flow of 5 kg / h, giving a 2.66% yield.