Differentiation of Green, White, Black, Oolong, and Pu-erh Teas According to Their Free Amino Acids Content

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• 作者：A. Alcá ; zar ; O. Ballesteros ; J. M. Jurado ; F. Pablos ; M. J. Mart&iacute ; n ; J. L. Vilches ; A. Navaló ; n
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2007
• 出版时间：July 25, 2007
• 年：2007
• 卷：55
• 期：15
• 页码：5960 - 5965
• 全文大小：163K
• 年卷期：v.55,no.15(July 25, 2007)
• ISSN：1520-5118

文摘

In this paper, the differentiation of green, black, Oolong, white, and Pu-erh teas has been carried outaccording to their free amino acid contents. Alanine, arginine, asparagine, aspartic acid, glutamicacid, isoleucine, histidine, leucine, phenylalanine, serine, theanine, threonine, and tyrosine have beendetermined by liquid chromatography with derivatization with o-phthalaldehyde and fluorescencedetection. The chromatographic separation was achieved with a Hypersil ODS column and gradientelution. The amino acid contents were used as chemometric descriptors for classification purposesof different tea varieties. Principal component analysis, k-nearest neighbors, linear discriminantanalysis, and artificial neural networks were applied to differentiate tea varieties. Using back-propagation multilayer perceptron artificial neural networks, 100% success in the classification wasobtained. The most differentiating amino acids were glutamic acid, asparagine, serine, alanine, leucine,and isoleucine.