基于稀土元素含量的普洱茶产地识别研究

为了研究普洱茶产地识别技术,收集普洱茶三大主产区（西双版纳、普洱市、临沧市）的普洱生茶和普洱熟茶代表性样本共85个,采用等离子发射光谱质谱法（ICP/MS）测定了样本的16种稀土元素含量,并进行了主成分分析和逐步判别分析研究。结果表明,对3个地区的普洱生茶和普洱熟茶样本,分别进行线性判别分析的回判成功率和验证成功率都为100%。对3个地区的混合样本进行判别分析的回判成功率分别为93.3%、87.9%、90.9%,交叉验证的正确率分别为90%、87.9%、90.9%,18个外部验证样本的正确判别率为84.6%、81.4%、82.9%。本研究表明,通过稀土元素含量的线性判别分析,能够较好地区分三大主产区的普洱茶样品。

The Discrimination of Pu'er Tea According to Region of Origin Using the Content of Heavy Rare-earth Elements

Pattern recognition techniques were studied to classify the Pu’er tea on the basis of their geographical origin. In this experiment, 85 samples of Pu’er tea in three mainly origin regions (Xishuangbanna, Pu’er and Linchang city) were collected as experimental samples. 16 heavy rare-earth elements in Pu’er tea samples were determined by using inductively couple plasma-mass spectrometry (ICP-MS). Principal component analysis (PCA) and discriminant analysis of Wilk’s method were used as classification procedures. The recognition accuracy for the training samples (Pu’er shu tea and Pu’er sheng tea) on three origin regions were all 100%, cross-validating were 100%. The recognition accuracy for the training samples (mixture of Pu’er shu tea and Pu’er sheng tea) on Xishuangbannan, Pu’er and Linchang city set was 93.3%, 87.9%, 90.9 %, respectively; cross-validating were 90%, 87.9%, 90.9%, respectively. The recognition accuracy for the testing 18 samples were 84.6 %、81.4%、82.9% respectively. Those results revealed that it was possible to distinguish three mainly origin regions of Pu’er tea by the contents of heavy rare-earth elements.