Selection of Optimal Operating Conditions for Extraction of L. Essential Oil by the Steam Distillation Method.

L. is one of the important aromatic and medicinal species from the Mediterranean area. It is used in various fields such as culinary, cosmetic, pharmaceutical, therapeutic, and industrial applications. Thus, a Box-Wilson experimental plan was used in this study to select the optimal operating conditions in order to obtain high volumes of essential oils. The factorial design method was applied to evaluate at an industrial scale the effect of major process variables on the essential oil extraction from L. herbs by the steam distillation method. The input variables considered as significant operating conditions were: X-boiler occupancy rate (boilers were filled to 50%, 75%, and 100%), X-distillation duration (distillation was continued 60, 75, and 90 min), and X-particle size (herbs were cut in sizes of 10, 20, and 30 mm via guillotine). The dependent variable selected, coded as Y, was the essential oil volume obtained (mL). The steps of the classical statistical experimental design technique were complemented with the Taguchi method to improve the extraction efficacy of essential oil from L., and the optimum parameter conditions were selected: boiler occupancy rate 100%, distillation duration 75 min, and particle size 20 mm. Following the optimum parameters, the GC-MS assay revealed for the L. essential oil two predominant components, α-pinene-33.14% and eucalyptol-55.09%.