Polyphenolic Profile and Antioxidant Activities of Oolong Tea Infusion under Various Steeping Conditions

International Journal of Molecular Sciences

Xinguo Su¹  Jun Duan¹  Yueming Jiang¹  Xuewu Duan¹ 

[1] South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650; P. R. China; E-mail:

关键词: Oolong tea;    Infusion;    Antioxidant activity;    Phenolics;   

DOI  :  10.3390/i8121196

来源: mdpi

【 摘 要 】

The phenolic profile and antioxidant activities of oolong tea extract were investigated after tea was steeped in 90 or 100 °C water for 3 or 10 min. The extraction yield increased with increasing temperature and extended steeping time. However, higher temperature and longer time (100 °C water for 10 min) led to loss of phenolics. The aqueous extract of oolong tea (AEOT) at 100 °C for 3 min exhibited the strongest antioxidant activity. The major polyphenolic components of the AEOT were identified as (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCG) and (−)-epicatechin-3-gallate (ECG). The two major catechins (EGC and EGCG) in the tea infusion contributed significantly to the investigated antioxidant activities [i.e., the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical scavenging and superoxide radical scavenging activities] with high correlation values in r = 0.9486 and 0.9327 for the EGC and r = 0.9592 and 0.8718 for the EGCG, respectively.

【 授权许可】

Unknown   
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