储藏时间对贡眉白茶主要内含成分及抗氧化活性的影响

Effect of Storage Time on Main Components and Antioxidant Activity of Gongmei White Tea

以5个不同年份的贡眉白茶为原料,主要通过分光光度计法和方差分析方法研究储藏时间对贡眉白茶水浸出物、茶多酚、咖啡碱、游离氨基酸含量及其对DPPH和羟自由基清除率的影响。结果表明:5个不同年份茶样的主要成分含量分别为水浸出物含量32.12%~45.46%,茶多酚含量15.05%~19.31%,咖啡碱含量3.17%~3.67%,游离氨基酸含量1.65%~3.59%;体外抗氧化能力显示,其对DPPH清除率在74.77%~85.83%,对羟自由基清除率在68.25%~74.56%;随着储藏时间的延长,5个样品中水浸出物、茶多酚、游离氨基酸总量、抗氧化活性都呈下降趋势,而咖啡碱含量呈波浪形变化,经过方差分析得出,年份间各成分含量和抗氧化活性变化都达到极显著差异(P<0.01)。

Five different years of Gongmei white tea were used as raw materials.The effects of storage time on the contents of water extract,tea polyphenols,caffeine,free amino acids and their scavenging rates on DPPH and hydroxyl radicals were studied by spectrophotometer and variance analysis.The results showed that the main components of tea samples in fve different years were water extract content of 32.12%-45.46%,tea polyphenol content of 15.05%-19.31%,caffeine content of 3.17%-3.67%,and free amino acid content of 1.65%-3.59%.The antioxidant capacity in vitro was 74.77%-85.83%for DPPH scavenging rate and 68.25%-74.56%for hydroxyl radical scavenging rate.With the extension of storage time,the water extract,tea polyphenols,total free amino acids and antioxidant activity of the fve samples showed a downward trend,while the caffeine content showed a wavy change.After variance analysis,the content of each component and antioxidant activity were signifcantly different between years(P<0.01).