Modeling of Optimized Supercritical Carbon Dioxyde Extraction of Essential Oils from Hyssop (Hyssop officinalis), Thyme (Thymus serpullum) and Valerian (Valeriana officinalis)

摘要

The aim of this work was to model the process of carbon dioxide supercritical fluid extraction (SFE) of essential oils from different plant material. Two models were applied on experimental results: the widely used model of Sovova which is universal and describes the SFE process regardless of the plant material; and the model based on the secretory structure of the plant material which is strongly dependant on the type of oil storage within the plants. These models were used to describe two types of SFE processes: the classical SFE, in which grounded plant material is loaded into the extractor vessel, and after reaching operational conditions, supercritical extraction takes place immediately; and the optimized SFE, in which the plant material is subjected to pretreatment which includes exposing the grounded plant material to supercritical fluid at operational conditions for chosen amount of time (batch operation) prior to the continuous process of SFE. The pretreatments were found to be optimal for selected plants regarding their secretory structure. Both models showed good agreement with experimental results, and values of the model parameters showed the influence of supercritical carbon dioxide on plant material during the pretreatment period.