不同發酵程度茶葉之抗氧化能力比較分析

Comparison of Antioxidative Activities of Tea with Different Fermentation Degree

張淑芬(Shu-Fen Chang)

指導教授 ： 劉炳嵐

朝陽科技大學/理工學院/應用化學系/碩士(2013年)

摘要

摘要

茶是東南亞栽培最廣的經濟作物，近年來國內外學者對不同產地多樣品種的茶，進行各項動物試驗或臨床試驗，證實茶具有抗氧化、提高機體免疫功能、防止紫外線輻射引起的DNA損傷，且能降低血液中三酸甘油脂含量及減少脂肪堆積等功效。故今日臺灣的茶已不僅為解渴的飲料，更多人將之視為預防疾病及增強體質之健康飲品。本論文的研究目的是以市售不同發酵程度之茶葉為實驗材料，探討不同發酵程度茶葉中總酚含量之差異，並分析其還原力、清除DPPH自由基能力，探討發酵程度與抗氧化能力之關連性，以作為國人健康茶飲之參考。實驗結果得知，茶葉中之總酚含量隨著發酵程度的增加而遞減，依序為不發酵茶(304.11 mg GAE/g)、輕發酵茶(241.14 mg GAE/g)、重發酵茶(208.55 mg GAE/g)、全發酵茶(162.40 mg GAE/g)。還原力的測定整體表現為：不發酵茶(20.58 μg Vit. C/mL)＞重發酵茶(16.30 μg Vit. C/mL)＞輕發酵茶(14.16 μg Vit. C/mL)＞全發酵茶(14.90 μg Vit. C/mL)。若與總酚含量相比，還原力與總酚類化合物含量之間除了不發酵茶有正向關係之外，其餘發酵茶則無顯著相關。在清除DPPH自由基方面，以不發酵茶清除率最佳，其甲醇萃取物(100 μg/mL)之清除率可達70.11%，其次為輕發酵茶(53.37%)、重發酵茶(44.86%)、全發酵茶(41.83%)。茶葉發酵程度越低，清除DPPH自由基的清除能力越佳，兩者有顯著相關。綜合研究發現，茶葉發酵程度越低，其總酚類化合物之含量越高，所呈現之抗氧化能力也越強。

關鍵字

茶 ； 發酵程度 ； 總酚含量 ； 抗氧化能力 ； 清除DPPH自由基

並列摘要

Abstract

Tea is the most widely-cultivated cash crop in Southeast Asia. Recently studied have shown the strong or comparable scavenging activities, enhance immunity, prevent from DNA damage caused by ultraviolet radiation, lower the blood triglyceride levels, and decrease fat accumulation both in vitro and in vivo on the various tea from different countries. Consequently, Taiwanese tea is not merely the drink for people to quench their thirst, but also is considered to prevent them from illness and enforce their physical vigor. The aims of this research were to explore the antioxidative activity of tea with differences fermentation degrees in terms of total phenolic content (TPC), DPPH free radical scavenging activity, and reducing power. As results, the TPC was increases while the degree of fermentation was decreased. The TPC for unfermented tea was found to be 304.11 mg GAE/g, lightly fermented tea was 241.14 mg GAE/g, deeply fermented tea (208.55 mg GAE/g), and fully fermented tea (162.40 mg GAE/g). The overall performance for the reducing power was: unfermented tea (20.5 μg Vit. C/mL) > deeply fermented tea (16.3 μg Vit. C/mL) > lightly ermented teas (14.16 μg Vit. C/mL) > fully fermented tea (14.9 μg Vit. C/mL). Accordingly, the reducing power and TPC have a positive relationship on unfermented tea, but no significant influence on the fermented tea. The methanol extracts (100 μg/mL) of unfermented tea exhibited a best DPPH free radical scavenging activity (70.11%), followed by the lightly fermented teas (53.37%), deeply fermented tea (44.86%), and fully fermented tea (41.83%). Obviously, the lower in the fermentation degree of tea, the better of DPPH free radical scavenging ability were observed. In conclusion, the lower in the fermentation degree of tea, the higher the TPC and the antioxidative activity were obtained.

並列關鍵字

Tea ； Fermentation degree ； Total phenolic content ； Antioxidative activity ； DPPH free radical scavenging

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