基于^(1)H-NMR的名山古树普洱茶判别初探

Study on Identification of Pu-erh Tea from Ancient Tea Plant Varied with Famous Tea Mountains Based on^(1)H-NMR

以云南省西双版纳州贺开古茶山曼竜村、布朗古茶山老曼峨村、易武古茶山落水洞村3个不同名山古树茶普洱茶为材料,基于核磁共振氢谱(^(1)H-NMR)建立判别模型,对不同名山古树普洱茶进行判别初探。采用^(1)H-NMR得到5种儿茶素(表没食子儿茶素没食子酸酯、表没食子儿茶素、表儿茶素没食子酸酯、表儿茶素、儿茶素)、6种氨基酸(茶氨酸、丙氨酸、苏氨酸、异亮氨酸、缬氨酸、亮氨酸)、4种有机酸(奎尼酸、醋酸盐、脂肪酸、没食子酸)、4种糖类(α-葡萄糖、β-葡萄糖、果糖、蔗糖)、咖啡因和2-O-阿拉伯吡喃糖基肌醇总共21个化学成分。通过PCA-Class模式判别分析,可明显将老曼峨生茶和熟茶进行有效判别。对不同茶山古树普洱茶生茶的判别结果表明,布朗古茶山样本判断正确率达100.00%,而贺开古茶山和易武古茶山样本均有判别错误现象,其模型判别综合正确率仅为58.33%。因此,基于^(1)H-NMR能对同一名山不同加工工艺所得古树普洱茶进行有效判别,而对同一区域内不同名山古树普洱生茶判别有一定局限性。

Identification model was established based on nuclear magnetic resonance hydrogen spectroscopy(^(1)H-NMR)to distinguish Pu-erh tea of ancient tea plants from three famous tea mountains,namely Hekai ancient tea mountain,Bulang ancient tea mountain,and Yiwu ancient tea mountain in Xishuangbanna prefecture,Yunnan province.Totally 21 components were obtained by^(1)H-NMR,including five catechins(epigallocatechin gallate,epigallocatechin,epicatechin gallate,epicatechin and catechin),six amino acids(theanine,alanine,threonine,isoleucine,valine and leucine),four organic acids(quinic acid,acetate,fatty acid and gallic acid),four sugars(α-glucose,β-glucose,fructose and sucrose),caffeine and 2-O-arabopyranositol.Moreover,raw and ripe Pu-erh tea samples of the same tea mountain could be effectively distinguished by PCA-Class pattern discriminant analysis.Furthermore,the discrimination results of raw Pu-erh tea from different famous tea mountains showed that the accuracy of samples from Bulang ancient tea mountain was 100%,while the samples from Hekai and Yiwu ancient tea Mountains were misidentified.Thus,the model accuracy of discrimination was 58.33%.Therefore,^(1)H-NMR could effectively distinguish Pu-erh tea from the same tea mountain varied with different processing techniques,however there were some limitations in distinguishing raw Pu-erh tea of ancient tea plants from different famous tea mountains in the same region.