Supercritical fluid extraction and analysis of phytochemicals

The overall objective of this thesis was to study supercritical fluid extraction of compounds from botanicals and byproducts of the food processing industry. These are: kavalactones, citrals, and lycopene. Kavalactones were extracted from kava (Piper methysticum Frost) and citrals were extracted from lemon balm (Melissa officinalis), lemon bergamont (Monarda citriodora), lemon eucalyptus ( Eucalyptus citriodora), and lemongrass (Cymbopogon citratus). Lycopene was extracted from tomato seeds and skins (byproduct of the tomato processing industry). Kavalactones have been reported to have soporific, bactericidal, and antimycotic properties, while citral compounds are utilized extensively in the flavor and fragrance industry. Lycopene is predominately found in tomatoes to which it imparts the rich red color. Increased levels of serum lycopene levels in humans has been linked to decreased incidence of certain types of cancer. Supercritical CO2 extraction resulted in kavalactone extracts being produced faster and more efficiently than conventional solvent extraction. Similar results were found when supercritical fluid extraction was used with lemon-scented botanicals. In the case of lemongrass and lemon eucalyptus, supercritical fluid extraction produced additional compounds not usually found in the hydrodistillates of either plant, indicating that supercritical fluid extraction may be better suited as an analytical method. Experiments showed that lycopene could be extracted from tomato seeds and skins using supercritical carbon dioxide without modifiers. The extraction conditions that produced the maximum amount of lycopene were 86°C and 34.47 MPa. A novel method analyzing tocotrienols, tocopherols, and carotenoids simultaneously using reversed-phase HPLC coupled with electrochemical detection was developed to facilitate analysis of the extracts produced from the tomato seeds and skins. This method was capable of measuring (in order of elution) δ-tocotrienol, γ-tocotrienol, α-tocotrienol, δ-tocopherol, γ-tocopherol, α-tocopherol, lycopene, α-carotene, and β-carotene, and took 32 min per sample to perform. In summary, supercritical fluid extraction has been successfully applied to the extraction of an assortment of compounds, and a new method of HPLC analysis has been developed. The supercritical fluid extractions were performed without the aid of modifiers or co-solvents, and the method of analysis utilizes electrochemical detection to provide increased sensitivity in the detection of nine compounds