建立超臨界二氧化碳萃取山藥活性成分之方法

Abstract

摘 要 山藥(Dioscorea spp.)是台灣常見的食物，含有許多對人體有益的生理活性成分，同時也是許多藥品及健康食品的原料，目前文獻中萃取山藥活性成分的方法多是使用有機溶劑(例如：甲醇、乙酸乙酯、石油醚)，若要作為藥物或食品的原料將面臨溶劑殘留與溶劑回收處理的問題。本研究主要目的為建立超臨界二氧化碳(SC-CO2)萃取山藥生理活性成分的方法，以熱力學公式計算出超臨界二氧化碳與山藥中活性成分的溶解度係數(solubility parameter)。分別以32、42、52oC 三種溫度；4000、3000、2000 psi 三種壓力進行超臨界萃取，觀察不同溫度、壓力與溶解度係數之超臨界流體對不同山藥活性成分之萃取效果，並與有機溶劑萃取產物比較，以探討兩者萃取物活性成分之差異性。 超臨界二氧化碳之溶解度係數影響其萃取之產物，高溶解度之SC-CO2 與有機溶劑皆對薯蕷皂配基(diosgenin)溶解度較高，低溶解度係數之SC-CO2 與有機溶劑則對植物固醇(stigmasterol, β-sitosterol)溶解度較高。溶解度係數受溫度與壓力改變影響，於固定壓力下溫度每上升10oC 溶解度係數則減少4.4-13%，固定溫度時壓力每上升1000 psi溶解度係數增加4.6-17.5%。

Abstract Dioscorea spp. is a kind of common food and material for drug and health food in Taiwan. There are many scholars studied about biological active compounds of Dioscorea spp., and most of them get the compounds by using solvent extraction. Supercritical fluid (SCF), at the temperature and pressure above critical point, material will exhibit properties different from gas and liquid at the supercritical state and we can change the physical properties of SCF by control the temperature and pressure. Carbon dioxide has been widely used as the solvent for supercritical extraction due to its safety and availability. Solubility parameter (δ) provides a numerical estimate of the degree of interaction between materials, and can be a good indication of solubility. The objective of this study is to investigate the feasibility of extracting bioactive compounds from yam using supercritical carbon dioxide. The operating conditions, temperature, pressure and solubility parameter, will be studied. Organic solvent and supercritical carbon dioxide extraction shows similar results, High solubility parameter organic solven and SC-CO2 can extract more diosgenin, and low solubility parameter organic solven and SC-CO2 can extract more phytosterol (stigmasterol, β-sitosterol). The solubility parameter of supercritical carbon dioxide will be affect by changing pressure and temperature. It decreases 4.4-13%/10oC at fixed pressure and increases 4.6-17.5%/1000 psi at fixed temperature.