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|標題:||The adsorption and release of caffeine and four catechins in tea pot materials
|關鍵字:||茶壺;咖啡因;兒茶素;吸附;釋放;Tea pot;caffeine;catechins;adsorption;release||引用:||范嘉琦. 烘焙方法對茶葉中咖啡因含量之影響. 臺灣大學園藝學研究所學位論文 1-106, 2010. 張慧芳. 紫玉金砂. 中国科技财富 42-46, 2006. 黃文勇. 材料學概論, 2010. 李亞林. 紫砂茶壺. 南京大學出版社, 1996. 李景康, 張虹. 陽羡砂壼圖考. 百壼山館, 1937. 肖定全. 陶瓷材料, 2008. 阮逸明. 台灣之茶文化及其科學. 台灣茶葉研究匯報, 1997. 阮逸明. 臺灣的茶業 1-起源與發展. 稻田出版有限公司, 2001. 坪林茶葉博物館. 茶典. 聯經出版, 2004. 郁仁貽. 實用塑膠學. 徐氏基金會出版, 1997. 倪文, 李建平, 方興, 陳德平, 陳那那. 礦物材料學導論. 北京科學出版社, 1998. 國家圖書館. 中國古代茶道秘本五十種. 全國圖書館文獻縮微複制中心, 2003. 陳文照, 曾春風, 游信和. 材料科學與工程導論, 2005. 陳世春. 塑膠物性入門. 復漢出版社, 2002. 陳英玲. 茶葉的保健功效. 科學發展, 2005. 陸世英. 不鏽鋼概論. 中國科學技術出版社, 2007. 程苗根, 程超. 紫砂茶具概况. 農業考古, 2003. 萬妙玲, 賴杰诚, 賴政雄, 蔡江川, 黄秀英. 朱泥壺的世界. 壺中天地出版社, 2011. 詹勲華, 杜潔祥. 宜興陶器圖譜. 南天書局, 九壺館協助出版, 1982. 劉品均, 施佑蓉. 材料科學概論. 高立圖書有限公司, 2005. 劉修明. 中國古代飲茶與茶館. 臺灣商務印書館, 1998. 劉國雄, 林樹均, 李勝隆, 鄭晃忠, 葉均蔚. 工程材料科學 (修訂版), 1999. 鄭培凱. 茶與中國文化. 東アジア文化交渉研究別冊, 2008. 黄玉梅. 多樣化的茶類與不同茶具的搭配. 農業考古, 2010. 黄玉梅. 茶和茶具的搭配. 應用寫作, 2011. Ahmad N and Mukhtar H. Green tea polyphenols and cancer: biologic mechanisms and practical implications. 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與具有保健功效之兒茶素（EGC、EGCG、EC 及 ECG），評估壺質對該些成份吸附與釋放之能力，藉此探討壺質可能影響茶湯感官評斷之原因。實驗結果顯示，當以 250μg/mL 咖啡因進行吸附實驗時，紫砂壺在 10 分鐘時對咖啡因之吸附百分比為 3.2%，略高於其餘壺質，玻璃及塑膠壺最低約 1.1%。24 小時後，紫砂、朱泥、紅磚及白瓷壺之吸附百分比可達約 10% ，明顯高於其餘壺質；若將時間區分為前 10 分鐘、10 分鐘～1 小時、3~9 小時及 9~24 小時 4 個區段，可發現各壺質在前一小時之吸附百分比並無明顯變化，在第 3~9 小時開始有顯著的上升，以朱泥及紅磚壺上升幅度最大，而在第 9~24 小時之間，各壺質仍有 2~3%的上升。在兒茶素吸附實驗中，紫砂、朱泥及紅磚壺在 1 分鐘時對 4 種兒茶之吸附僅約0.5~1.6%，第 5 分鐘開始，各壺質之吸收有明顯上升，且大多以 EGC 的吸附百分比最高，塑膠壺為 EC，朱泥壺無一致性。第 10 分鐘時紫砂、朱泥及紅磚壺對4 種兒茶素之吸附百分比最高，但僅約為 4%，24 小時時則可達約 10~13%，紅磚、白瓷、不鏽鋼及玻璃壺皆對 EGC 之吸附最高，紫砂及朱泥壺則是 EC 較高；若將時間區分為 10 分鐘與 9~24 小時進行比較，各壺質對 4 種兒茶素之吸附，其百分比幾乎都有 2 倍以上的增加，而紫砂、朱泥、紅磚及白瓷壺更可達 3~5 倍，且百分比上升幅度最大之兒茶素皆為 EGCG 。當咖啡因與兒茶素同時存在時，發現紫砂、朱泥及不鏽鋼壺此兩類成份有相互競爭之情形，咖啡因吸附百分比較單獨存在時下降，紅磚與白瓷壺反而上升，玻璃及塑膠壺則無影響。在咖啡因與兒茶素之釋放實驗結果顯示，只有紅磚及紫砂壺能偵測到咖啡因的釋放，在第24小時，分別可測得 3.5 μg/mL 與 0.9 μg/mL 的濃度，紅磚壺可釋放較多咖啡因。在兒茶素的釋放方面，僅有紫砂壺可測得 EGCG ，其濃度在第 10 分鐘時約為 0.3 μg/mL，隨著時間的增加，其濃度反而逐漸下降，至第 24 小時，濃度僅餘 0.05 μg/mL，顯示所釋放之 EGCG 又有重新吸附回壺質內之現象。綜合以上結果，紫砂、朱泥及紅磚壺對咖啡因及兒茶素有較大的吸附能力，且吸收程度隨時間而上升，因此，可能導致對健康保健功效的影響。但就感官品嚐而言，兒茶素的吸收則有助於降低苦澀味。在咖啡因與兒茶素相互之影響方面，僅紫砂壺中咖啡因造成 EC 的吸附下降在統計上有顯著的差異。綜合以上本研究之結果，建立了各常見壺質對咖啡因及兒茶素之吸附現象及其相互影響之關係，初步提供壺質對茶湯感官評斷差異之科學證據。
It is well known that the flavor of tea is closely associated with the tea pot that the tea soup was made in. Tea pot material is believed to have effect on the sensory and nutritional performance of tea soup, but to this date, there has been no scientific explanation about how tea pot material can make such an effect on tea soup. The purpose of this study was to evaluate the adsorption and release behavior of caffeine and 4 catechins (EGC, EGCG, EC and ECG) by 7 commonly used tea pot materials including Zisha, Zhuni, red clay, ceramic, stainless steel, glass and plastic, in an attempt to find possible explanations on how the materials affect the sensory performance of the tea soup. When caffeine at 250 μg/mL was in a pot, the highest adsorption at 10 minute was by Zisha pot (3.2%) while the lowest was by glass and plastic pots (1.1%). Higher adsorption could be achieved (up to 10%) by Zisha, Zhuni, red clay and ceramic pots after 24 hours rat. At the time interval of 10 minute and 10~60 minute, all tea pots showed no difference in adsorption, but adsorption rate started increasing at 3~9 hours, with higher magnitude in Zhuni and red clay pots. Between 9~24 hours, the adsorption rate increased by another 2~3%. For the 4 catechins, the adsorption by Zisha, Zhuni and red clay pots was about 0.5~1.6% at one minute. After 5 minutes, the adsorption started increasing in all pot materials with the highest adsorption found in EGC (except for plastic and Zhuni pots). At 10 minutes, Zisha, Zhuni and red clay adsorbed the 4 catechins at around 4%, which elevated to 10~13% at 24 hours. Red clay, ceramic, stainless steel and glass pots adsorbed more EGC whereas Zisha and Zhuni pots adsorbed more EC. Comparison by two time intervals, the first 10 minute and 9~24 hours, the adsorption of catechins doubled in all pot materials and the adsorption of EGCG increased by 3~5 times in Zisha, Zhuni, red clay and ceramic pots. When caffeine and catechins coexisted in a tea pot, competition between caffeine and catechins were observed except for in the plastic and glass pots. At the presence of catechins caffeine adsorption decreased in Zisha, Zhuni and stainless steel while it elevated in red clay and ceramic pots. As for the releasing behavior, after 24 hours of adsorption, red clay and Zisha released caffeine at the level 3.5μg/mL and 0.9μg/mL, respectively. Only Zisha released detectable EGCG for up to 0.3μg/mL at 10 minutes, however, as the time passes, the catechin level in Zisha gradually decreased to 0.05μg/mL at 24 hours, suggesting the released EGCG was re-adsorption to the pot. In conclusion, of the 4 tea pot materials, Zisha, Zhuni and red clay adsorbed more caffeine and catechins than the other 4 pots, the effect may partially contribute to the lowering of the sensitivity to bitter taste. When caffeine and catechins were both present, only Zisha showed significant difference in decreasing EC. The current study revealed the association between caffeine and catechins and adsorbing effects of common tea pot materials and proved that tea pots can give rise to different tastes.
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