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熱泡與冷泡包種茶於靜置和浸泡過程中兒茶素組成之變化
Changes in Catechins of Hot and Cold Brewed Paochong Tea During Standing and Soaking
摘要
本研究探討冷泡和熱泡方式對包種茶湯成分的影響，並分析泡茶後靜置與浸泡過程中茶湯成分及抗氧化活性的變化，結果顯示熱泡包種茶湯主要的兒茶素為EGC、EC和GC等三種，冷泡包種茶湯主要兒茶素為EGCG、ECG、EGC、EC和GC等五種，二者皆以EGC的含量為最高。熱泡後茶湯於靜置15分鐘內，兒茶素含量並無顯著變化，靜置超過30分鐘至720分鐘，其含量則皆有顯著的下降，減少約30%-45%，顯示以兒茶素含量為指標時，熱泡包種茶於15分鐘內飲用較佳。而冷泡包種茶湯在浸泡6-12小時，各兒茶素的含量並無顯著的變化，繼續浸泡至24小時後，其含量則會顯著上升。咖啡因含量則不受靜置與浸泡時間的影響。比較熱泡和冷泡包種茶湯的差異，發現冷泡包種茶湯於浸泡超過8小時後，各兒茶素成分含量皆比熱泡包種茶湯為高。另外，冷泡包種茶在浸泡過程中的DPPH自由基清除能力與總兒茶素含量有顯著正相關，二者皆隨浸泡時間的延長而升高。
並列摘要
The purpose of this study was to determine the composition and content of catechins in hot and cold brewed Paochong tea. And, the effect of standing and soaking process of these two kinds of tea on catechins and antioxidant activity was also investigated. The results indicated that the major catechins in hot brewed Paochong tea were EGC, EC, and GC, while those were EGCG, ECG, EGC, EC, and GC in cold brewed Paochong tea. The most aboundant EGC was found in both of the Paochong tea. There was no significant difference in catechins content in 15 min standing of hot brewed Paochong tea. The catechins content of hot brewed Paochong tea decreased about 30-45% when standing time over 30 min to 720 min. Therefore, it is suggested that the best drinking time of hot brewed Paochong tea is within 15 min for ingesting the highest amount of catechins. For cold brewed Paochong tea, the content of catechins increased significantly after soaking for 24 hrs, while there was no significant different during 6-12 hrs soaking. No significant change of caffeine level was observed during standing and soaking. Comparing of hot and cold brewed Paochong tea, the content of catechins in cold brewed Paochong tea after 8 hrs soaking was higher than those in hot brewed Paochong tea. Besides, the DPPH free radical scavenging activity and total catechins content in cold brewed Paochong tea increased during soaking, which also showed good positive correlations.