TY - JOUR T1 - Differentiation of green, white, black, Oolong, and Pu-erh teas according to their free amino acids content. AU - Alcázar,A, AU - Ballesteros,O, AU - Jurado,J M, AU - Pablos,F, AU - Martín,M J, AU - Vilches,J L, AU - Navalón,A, Y1 - 2007/06/27/ PY - 2007/6/28/pubmed PY - 2007/10/10/medline PY - 2007/6/28/entrez SP - 5960 EP - 5 JF - Journal of agricultural and food chemistry JO - J Agric Food Chem VL - 55 IS - 15 N2 - In this paper, the differentiation of green, black, Oolong, white, and Pu-erh teas has been carried out according to their free amino acid contents. Alanine, arginine, asparagine, aspartic acid, glutamic acid, isoleucine, histidine, leucine, phenylalanine, serine, theanine, threonine, and tyrosine have been determined by liquid chromatography with derivatization with o-phthalaldehyde and fluorescence detection. The chromatographic separation was achieved with a Hypersil ODS column and gradient elution. The amino acid contents were used as chemometric descriptors for classification purposes of different tea varieties. Principal component analysis, k-nearest neighbors, linear discriminant analysis, and artificial neural networks were applied to differentiate tea varieties. Using back-propagation multilayer perceptron artificial neural networks, 100% success in the classification was obtained. The most differentiating amino acids were glutamic acid, asparagine, serine, alanine, leucine, and isoleucine. SN - 0021-8561 UR - https://www.unboundmedicine.com/medline/citation/17595106/Differentiation_of_green_white_black_Oolong_and_Pu_erh_teas_according_to_their_free_amino_acids_content_ L2 - https://doi.org/10.1021/jf070601a DB - PRIME DP - Unbound Medicine ER -