Aging time on antioxidant components and activities of Milan aromatic variety single-clump tea from Lingtou

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 l-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).