不同浸提方法对茶样中各儿茶素组分含量影响的比较

选取2个标准茶样为实验材料,采用高效液相色谱法检测,考察了GB/T 8313-2002《茶茶多酚测定》与GB/T 8313-2008《茶叶中茶多酚和儿茶素类含量的检测方法》中2种不同的茶汤浸提方法对茶样中儿茶素组分含量的影响。结果表明:在完全相同的实验条件下,3位实验人员采用GB/T 8313-2002中的沸水浸提法检测儿茶素各组分含量时,其中2位实验人员的测定结果差异不显著;而采用GB/T 8313-2008中的体积分数70%甲醇溶液浸提法检测时,3位实验人员所测定的结果在5%显著水平上差异显著,尤其是儿茶素中的酯型儿茶素的测定结果,差异达到极显著水平,且沸水浸提法与70%的甲醇水溶液浸提法相比,沸水浸提法儿茶素各组分含量的测定结果均高于70%甲醇水浸提法。表明在GB/T 8313-2008的茶汤浸提中,用沸水浸提法代替70%甲醇提取法可能更适于茶叶中儿茶素含量的测定。

Companison on Water Extraction and Methanol Extraction on the Quantitation of Catechins in Tea

using two tea standard samples,two different extraction methods from GB/T 8313 were compared to determine catechin content.The boiling water extraction method was adopted from former national standard GB/T 8313-2002 "Tea-Determination of tea polyphenols content" and methanol extraction is in the current national standard GB/T 8313-2008 "Determination of total polyphenols and catechins in tea".The results showed that the contents of catechins is very similar in water extraction method by three technicians,but have significant differences(at the 5% level of significance)when using methanol extraction.Particularly,the contents of catechin esters are different at the 1% level of significance.These suggest that boiling water extraction method is more suitable than methanol extraction method in the determination of catechin content in GB/T 8313-2008.