台灣市售茶飲料主要成份與清除自由基活性之相關性   全文下載

Correlation of Major Components and Radical Scavenging Activity of Commercial Tea Drinks in Taiwan

本研究調查台灣27種包含綠茶、烏龍茶及紅茶所製備之市售茶飲料的主要成份與清除自由基活性之相關性。綠茶飲料含最高總兒茶素含量，包含epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin (EC), epicatechin gallate (ECG)及gallocatechin gallate (GCG)，而這些成份則在紅茶飲料中含量低，在烏龍茶飲料中則為中等含量。EGC與EGCG為三種茶飲料中主要之兒茶素成份，而紅茶中含有最大量之沒食子酸(gallic acid)。三種茶飲料含有大約等量之咖啡因濃度。所有紅茶飲料皆含有糖，且以蔗糖為主要添加之甜味劑。利用捕捉1,1-diphenyl-2-picrylhydrazyl (DPPH)及2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)自由基能力來測定茶飲料之抗氧化能力，並且發現其能力依序分別為綠茶>烏龍茶>紅茶。茶飲料中總酚、總兒茶素及EGC含量與捕捉DPPH及ABTS自由基能力具有正向且高度（r > 0.8）相關。我們的結果顯示綠茶飲料比紅茶及烏龍茶飲料有較高清除自由基活性可能與其有較高之總酚及兒茶素含量有關。"

Correlation of major components with free radical scavenging activities of 27 commercial tea drinks prepared from green, Oolong, and black teas in Taiwan were investigated. Green tea drinks contained the highest level of total catechins including epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin (EC), epicatechin gallate (ECG), and gallocatechin gallate (GCG), while these components were low in black tea drinks and moderate in Oolong tea drinks. EGC and EGCG were the major catechins in the three types of tea drinks, and gallic acid showed the highest abundance in black tea drinks. Caffeine concentrations were comparable in the three types of tea drinks. All black tea drinks contained sugars, and sucrose was the main sweetener added. The scavenging abilities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals were used to determine the antioxidant potential of tea drinks, and the ranked order of potency was green tea > Oolong tea > black tea. Total phenolics, total catechins, and EGC of tea drinks were positively and significantly (r > 0.8) correlated to the scavenging abilities against DPPH and ABTS radicals. Our results show that green tea drinks have higher free radical scavenging activity than black and Oolong tea drinks may be related to their high levels of total phenolics and catechins.