Supercritical Fluid Extraction from Vetiver Roots: A Study of SFE Kinetics

摘要

The recovery of volatile oils from vegetal raw materials is an activity of great interest to the food, perfumes and cosmetic industries. The vetiver (Vetiveria zizanioides) oil is particularly appreciated in perfume and cosmetic products but may also be used in food industry as an aroma and as flavor agent in some beverage. The objective of this work, based on preliminary process parameters studies, is to improve the process - meaning both quantity and quality of the compounds - of vetiver extracts recovered by supercritical technology using carbon dioxide as supercritical fluid (SFE). Vetiver roots were purchased from a local producer in Brazil, dried, milled and classified. The extraction assays were carried out using the Spe-ed unit, unit I and II. The optimum extraction pressure was determined for the 40°C isotherm, for pressures in the range of 100 - 300 bar. The determined optimum pressure was used to study the influence of percentage of ethanol as co-solvent (0, 5 and 10% [v/v]). The chemical composition of the extracts was determined by gas and thin layer chromatography (GC and TLC, respectively). Overall extraction curves (OEC) were constructed allowing the determination of the kinetic parameters. The results of the extraction done using 10% of ethanol [v/v] were statistically different from 0 and 5% for global yield and kinetics parameters tCER, MCER and RCER. The TLC showed similar chemical profiles between SFE and hydrodistillation (HD), but there are some compounds that can be observed by TLC just during the tCER period.