| Summary: | 碩士 === 國立中興大學 === 農藝學系所 === 100 === Mint (Mentha spp.), which is belong to Labiatae, is a perennial aromatic herbs, it’s not only the most important raw material for essential oils on the world but also have many medical uses. In the present study, Mentha arvensis ssp. Haplocalyx (China mint), Mentha × rotundifolia ‘Julia’s Sweet Citrus’ (Julia’s sweet mint), Mentha × gracilis ‘Vietnam’ (Vietnam mint) and Mentha Canadensis (Native mint) were used to investigate the yield of shoot fresh weight, shoot dry weight, volatile oil content, menthol and menthone concentrations during annual cropping seasons, also compare the extract efficiency between conventional hydrodistillation and different condition of microwave-assisted hydrodistillation, and try to find a better way to prepare the menthol crystals in advance. The results showed that shoot weight, volatile oil content, menthol and menthone concentration, and volatile oil yield varied considerably among the selected species, cropping seasons, and extract methods. China mint grew better and produced more above-ground shoots than the others, but Julia’s sweet mint produced more volatile oil yield, particularly menthol in its shoot than Vietnam mint, Native mint and China mint. Generally, the yield of shoot weight, volatile oil production in second ratoon season were highest than the other cropping seasons. Extract efficiency indicated that hydrodistillation extracted more volatile oil content than microwave-assisted extraction, but less menthol concentration. In the crystallization trial , we can obtain the menthol crystal in 56% volatile oil under 4℃. Gradient cooling temperature and oil substitution during chilling phase provided a significant effects on the quality of menthol crystal.
|
|---|
