陈年普洱茶香气成分及清除DPPH自由基活性研究

Analysis of Aroma Components and DPPH· Scavenging Activity of Aged Pu-erh Tea

为研究陈年普洱茶的特征风味成分及生物活性,采用顶空-固相微萃取-气质联用法测定了3种陈年普洱茶中挥发性物质,结合质谱和保留指数共鉴定出57种化合物,其中甲氧基酚类、醇类及酮类化合物为主要香气成分。同时采用比色法测得3种普洱茶的沸水提取物的茶多酚含量分别为(41.91±1.98)、(43.84±2.56)及(41.28±2.57)mg GAE/(g·DW),并对3种普洱茶的1,1-二苯基苦基苯肼(DPPH·)自由基清除效果进行研究。结果表明3种普洱茶均具有较好的清除DPPH自由基能力,且呈剂量依赖性,测得3种普洱茶提取物清除DPPH·自由基的IC50分别为(129.03±0.25)、(139.47±1.58)及(152.57±3.34)mg GAE/L。

The aim of this study was to investigate the flavor characteristics and bioactivity of aged Pu-erh tea.Volatile compounds from aged Pu-erh tea were measured using solid-phase micro-extraction（SPME） and gaschromatography-mass spectrometry（GC-MS）. Results showed that a total of 57 volatile compounds wereidentified by matching EI mass spectra and retention indices with the literature data. Alcohols,methoxy-phenolic and ketones were the three major aromatic groups. The total phenolic contents of three typesof Pu-erh tea were（41.91±1.98）,（43.84±2.56） and（41.28±2.57） milligrams of gallic acid equivalent per gramof dried weight [mg GAE/（g·DW）]. The effects of Pu-erh tea extracts on the 2,2-diphenyl-1-picrylhydrazylradical（DPPH ·） scavenging activity were evaluated. The results showed that all types Pu-erh tea extractsexhibited the relative strong DPPH· scavenging activity and in dosage-dependent modes. The concentration ofsample required for 50% inhibition of DPPH ·（IC50） were（129.03 ± 0.25）,（139.47 ± 1.58） and（152.57±3.34） mg GAE/L, respectively.