Research on the Extraction of Plant Volatile Oils

Microwave-assisted extraction will probably be the main technique in the near future for industrial essential oil production. Two kinds of new methods for essential oil extracting were used in this paper: microwave-assisted extraction (MAE) and supercritical carbon dioxide extraction (SC-CO2). The steam extraction system was designed by ourselves, according to Chinese Pharmacopoeia. The device has a double advantage of the fast with microwave assisted extraction and of high purification with the Chinese Pharmacopoeia. The optimum extraction conditions for SC-CO2 were obtained by parallel and uniform design experiments, and searched for the method of purifying product by reduced pressure distillation. The compare of the volatile oils from Lavender from the two extractions was made via gas chromatography. The optimum conditions of Lavender essential oil extracted by supercritical CO2 extraction process: extraction pressure 22 MPa, extraction temperature 45 °C, extraction time of 1 h, and the factors influence on the extraction rate is: extraction pressure> extraction temperature> extraction time. The yield of the product extracted under the optimal conditions was 4.80%. The results from GC analysis show that: the amount of the component of lavender essential oil is 84 obtained by microwave combination of steam distillation with more than of 0.05% before the retention time of 40 minutes, compared with supercritical received only 65. The microwave-assisted extraction combined steam distillation is a good process for sample pretreatment with convenient operation and high effective ingredient, and is more suitable for analysis. The supercritical carbon dioxide extraction is a good method with high yield, high relative content and large treat amount for industrial production.