摘要
綠茶是世界上最受歡迎的飲料之一，其富含豐富的兒茶素、多酚、維生素C等抗氧化成分，營養價值為幫助人體消除體內自由基。現今茶類的選擇愈來愈多，但實際上其營養以及抗氧化物質是本研究的重點，本研究將以未發酵茶之綠茶為主要研究對象，並比較發酵茶之烏龍茶與紅茶抗氧化成分之比較。 本篇研究分為兩個部分，第一部分是針對三種不同綠茶茶葉進行六大抗氧化成份研究，包含DPPH(α,α-diphenyl-β-picrylhydrazyl)、FRAP(Ferric ion Reducing Antioxidant Power)、總多酚、總類黃酮、水解單寧、縮合單寧等六種抗氧化能力檢測方法找出最佳化萃取條件。第二部分為利用前述最佳化條件檢測發酵茶之烏龍茶及紅茶茶葉，再利用上述六種抗氧化能力檢測方法，藉由紫外光/可見光分析儀(UV/VIS)作為抗氧化物質檢測工具。 研究結果顯示，透過了最佳化萃取條件，以及抗氧化能力與類黃酮等檢測，未發酵綠茶，無論是在DPPH清除能力、還原能力、總酚含量測定上，都皆有最佳表現。若消費者在選擇茶飲時，以抗氧化能力為考量或想攝取較多的酚類化合物為考量時，未發酵綠茶是個好的選擇。
並列摘要
Green tea is one of the most popular beverages in the world. It is rich in beneficial components such as catechins, polyphenols, and vitamin C, which are known for their antioxidant properties and their ability to help eliminate free radicals in the body. Nowadays, there are various types of tea available, but the focus of this study is to explore the nutritional and antioxidant properties of green tea, oolong tea, and black tea leaves. This study consists of two parts. The first part focuses on researching three different types of green tea leaves. Six antioxidant capacity testing methods, including DPPH (α,α-diphenyl-β-picrylhydrazyl), FRAP (Ferric ion Reducing Antioxidant Power), total polyphenols, total flavonoids, hydrolyzable tannins, and condensed tannins, are used to identify the optimal extraction conditions. In the second part, oolong tea and black tea leaves are added to the samples. The six antioxidant capacity testing methods mentioned earlier, along with UV/VIS spectroscopy, are employed to detect the differences in antioxidant content among green tea, black tea, and oolong tea. The research results indicate that non-fermented green tea shows the best performance in terms of DPPH scavenging capacity, reducing power, and total phenolic content when optimal extraction conditions and antioxidant capacity and flavonoid testing are considered. Therefore, non-fermented green tea is a good choice for consumers who prioritize antioxidant capacity or seek to intake more phenolic compounds when selecting tea beverages.