Effect of tea cooking time on antioxidant activities of Zijuan puer tea

It was investigated that the effect of tea cooking time and two times of cooking on antioxidant activities of Zijuan puer tea. The contents of total monomeric anthocyanin, total phenols and total flavonoids were determined. The relation between hydroxyl radical scavenging activity,DPPH radical scavenging activity,total antioxidant activity and reducing power of tea extractions and the contents of these active ingredients was tested. The results indicated that within 10 minutes of tea cooking,the contents of active ingredients enhanced with time,however,the amplification decreased with time. After 7 minutes of tea cooking for one time,the increase of total contents of different types of active ingredients almost tended to be steady. The total content of different types of active ingredients in Zijuan puer tea apparently decreased after two times of cooking(p<0.05). The hydroxyl radical scavenging activity and total antioxidant activity of Zijuan puer tea showed a positive linear correlation with the contents of active ingredients,which was more apparent with the contents of total monomeric anthocyanin and total phenols(R2>0.8).