不同贮藏年份蜜兰香型岭头单丛茶抗氧化成分及抗氧化活性

摘要

The single-clump teas aged for 5 years,10 years,15 years and 20 years were used as materials.the content of the main antioxidant components (tea polyphenols,flavonoids,free amino acids,theaflavins,catechins and caffeine)and antioxidative activities of single-clump teas of Milan aromatic variety from Lingtou were determined,also the correlations were investigated.The control was processed in 2016.The results showed that the content of tea polyphenols,flavonoids and catechins increased,the content of both free amino acids and caffeine reduced,the theaflavins contents increased and then reduced during 20 years storage.The scavenging abilities of DPPH(1,1-bipheny 1-2-picrylhy drazyl)radicals and hydroxylradicals,inhibiting ability of superoxide radicals and reducing power for single-clump tea water extracts were different in different aging time.The antioxidant capacity was evaluated by the APC (antioxidant potency composite index).It was observed that the antioxidant capacity was in the decreasing order:20 years ＞ 10 years ＞ 15 years ＞ 5 years ＞ the control.The correlation analysis revealed that the scavenging ability of single clump tea water extracts on DPPH radicals and hydroxyl radicals was significantly positively correlated with the content of tea polyphenols,flavonoids and catechin (p ＜ 0.05).Both reducing power and inhibiting ability on superoxide radicals did not related significantly to the main antioxidant components(p ＞0.05).%测定了贮藏5、10、15、20年和2016年制作(实验当年做为对照)的蜜兰香型岭头单丛茶中茶多酚、黄酮、游离氨基酸、茶黄素、儿茶素和咖啡碱等几种抗氧化成分的含量及其抗氧化活性,并研究了两者之间的相关性.结果表明:在20年贮期内,随着贮藏时间的延长,蜜兰香型岭头单丛茶的茶多酚、黄酮和儿茶素含量上升,游离氨基酸和咖啡碱含量下降,茶黄素含量先上升后下降.不同贮藏年份的岭头单丛茶清除DPPH自由基和羟自由基的能力,抑制超氧阴离子自由基的能力及还原力均有差异,通过综合指数(APC)评价抗氧化能力结果可知:抗氧化活性贮藏20年＞10年＞15年＞5年＞对照.单丛茶水提物对DPPH自由基和羟基自由基的清除能力与茶多酚、黄酮、儿茶素的含量呈显著性正相关(p＜0.05).还原能力和抑制超氧阴离子自由基能力与各抗氧化成分之间相关性不显著(p＞0.05).