Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/93024
標題: The adsorption and release of caffeine and four catechins in tea pot materials
壺質對咖啡因及四種兒茶素類茶湯成份吸附與釋放之影響
作者: Ying-Zhi Lin
林英至
關鍵字: 茶壺;咖啡因;兒茶素;吸附;釋放;Tea pot;caffeine;catechins;adsorption;release
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摘要: 
在飲茶的文化中,茶與壺有著密不可分的關係。喝茶講究茶湯之色澤、香氣、
韻味及保健養生功效,而壺質飲具對茶湯風味表現的影響,目前大多依賴人為感
官評論與經驗傳承,尚未有大量的科學證據支持。本研究選用紫砂、朱泥、紅磚、
白瓷、不鏽鋼、玻璃及塑膠等七種不同壺質,針對茶湯成份中含量最高之咖啡因
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.
URI: http://hdl.handle.net/11455/93024
其他識別: U0005-0209201313311800
Rights: 同意授權瀏覽/列印電子全文服務,2016-09-02起公開。
Appears in Collections:獸醫學系所

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