Study On Supercritical Carbon Dioxide Extraction Of Clove Oil And It's Application In Postharvest Storage Of Fruits And Vegetables

Clove oils extracted from Buds of clove ((Eugenia caryophyllata Thunb.) have been used in traditional Chinese medicines and flavoring agent. It is reported that clove oils also have antifungal and insecticidal functions. Traditional extraction methods for clove oil are steam distillation and solvent extraction. Supercritical carbon dioxide extraction (SFE) is considered as a new and green process for the essential oil extraction. The objective of this project is to study the process of extracting clove oil with supercritical CO₂ (SC-CO₂), and to compare the quality of clove oils extracted by SFE with traditional methods. In addition, the basic theoretical research on the mass transport process of SFE and the solubility of clove oils were also studied. At last, the antifungal activity of clove oils and its application in pepper storage were also studied.Extraction of clove oil with SC-CO₂ was firstly investigated, and the orthogonal array design was used to explore the influences of temperature, pressure and particle size on the yield and the content of main components in the extracted clove oil. The experimental results showed that the yields of clove oil extracted from clove buds were 17.67%²0.16 % at temperature of 50℃and pressures ranging from 10 MPa to 15 MPa. The composition and the quality of the clove oils extracted by different methods, including SFE, hydro distillation, steam distillation and soxhlet extraction, were further compared. The analytical results by GC showed that, the content of eugenol and eugenol acetate in clove oil extracted by SFE is 58.8% and 19.6%, respectively. Twenty three compounds in the clove oils have been identified by GC/MS, and the relative content of eugenol, eugenol acetate andβ-caryophyllene is totally higher than 90%. The oil yield extracted with SC-CO₂ under optimal conditions is about twice as that by hydro distillation or steam distillation. Additionally, the apparent characteristics, such as no solvent residues existed in the extracted oil, shorter extraction time and so on, indicated that SFE could be one of the most clean and highly effective technology for processing essential oil from the plants.Based on the material balances, a mathematical model was founded by lumped parameter method and then simplified so that it can be employed to simulate the SFE process of clove oil. The simulating results showed that the model fits the experimental data with average relative errors (AARD ) ranging from 6.88～57.78%. The solubility of eugenol, eugenol acetate andβ-caryophyllene in supercritical CO₂ was separately determined with dynamic method at the temperatures ranging from 313 K to 333K and pressures from10 MPa to 30MPa. The experimental results showed that the solubilities of eugenol in SC-CO₂ were between 0.0002 and 0.0580 (mole fraction). The solubilities of eugenol acetate in SC-CO₂ were between...