- 期刊
以溫室氣體二氧化碳結合超臨界技術萃取茶葉中茶多酚探討之研究
Study on Extraction of Polyphenols from Oolong Tea by Greenhouse Gas Carbon Dioxide with Supercritical Fluid Technology
摘要
超臨界萃取在開發與應用中發現超臨界二氧化碳液體萃取擁有多項優點，如無毒性、溶劑殘留、且具有液體的密度、溶解能力和良好的流動性，同時又具有氣體的擴散係數和低黏度等。本研究是利用超臨界二氧化碳批式萃取技術從茶葉中萃取茶多酚。以茶葉重量、共溶劑乙醇的添加量、萃取壓力、萃取溫度、萃取時間與洩壓流速作為超臨界二氧化碳萃取之操作變因，配合一次一變因法進行探討，並找出最適萃取條件。實驗結果發現，超臨界300mL萃取之最適萃取條件為茶葉添加量5.0g、共溶劑乙醇的添加量60.0mL、萃取壓力4500psi、萃取溫度60℃、萃取時間50.0min及洩壓流速6.0NL／min，所萃出的茶多酚含量為105.58mg／g，而經由多次萃取累積增加萃取次數達12次後可得208.76mg／g；超臨界1000mL萃取之最適條件為茶葉添加量15.0g、共溶劑乙醇的添加量360.0mL、萃取壓力4500psi、萃取溫度60℃、萃取時間50.0min及洩壓流速18NL／min，可萃出總茶多酚含量為184.57mg／g，經由多次萃取累積增加萃取次數達12次後可得208.85mg／g。
並列摘要
Supercritical CO_2 fluid is widely used as the extractant due to its nontoxic nature, relatively lower price, higher diffusivity, lower critical temperature and lower critical pressure. Therefore, supercritical CO_2 fluid extraction (SFE-CO_2) is an increasingly important processing technique for extracting functional compounds from plant materials. In this research, SFE-CO_2 was used to extract polyphenols from oolong tea and studied the scale-up of extraction vessel of SFE-CO_2 from 300 mL to 1000 mL. The operation parameters included oolong tea weight, addition volume of ethanol modifier, extraction pressure, CO_2-flow rate, extraction time, extraction temperature and ethanol composition (in water). The optimum conditions of 300 mL extraction vessel were oolong tea weight 5.0 g, addition volume of ethanol modifier 60.0 mL, ethanol composition 60.0%, extraction pressure 4500.0 psi, extraction temperature 60.0℃, extraction time 50.0 min and CO_2-flow rate 6.0 NL/min. Under SFE-CO_2 optimum conditions, the tea polyphenol contents were 105.58 mg_(Galic acid) per 1g dry oolong tea. 12 cycles extraction, the accumulation amount of tea polyphenols was 208.76 mg_(Galic acid) per 1g dry oolong tea. The optimum conditions of 1000 mL extraction vessel were oolong tea weight 15.0 g, addition volume of ethanol modifier 360.0 mL, ethanol composition 60.0%, extraction pressure 4500.0 psi, extraction temperature 60.0℃, extraction time 50.0 min and CO_2-flow rate 18.0 NL/min. Under SFE-CO_2 optimum conditions, the tea polyphenol contents were 184.57 mg_(Galic acid) per 1g dry oolong tea. 12 cycle extraction, the accumulation amount of tea polyphenols was 208.85 mg_(Galic acid) per 1g dry oolong tea.