Identification and chromatographic determination of bioactive components in the instant coffee samples

Abstract

This work is devoted to the identification of chlorogenic acids and their lactones as well as to the determination of the main isomers of these acids and caffeine in the instant coffee samples by HPLC-UV-MS. The features of HPLC determination of bioactive components (alkaloids and phenolic compounds) in coffee are discussed. The conditions for chromatographic separation of the main phenolic compounds - isomers of chlorogenic acids (CGA) and their derivatives, as well as for the caffeine in instant coffee, are selected. As a result of these studies the major components corresponding to the main isomers of caffeoylquinic acids (CQA) - 5-caffeoylquinic acid (5-CQA), 3-caffeoylquinic acid (3-CQA) and caffeine were identified. Using the literature data and the results of HPLC-UV-MS analysis the isomers of caffeoylquinic acids, feruloylquinic acids (FQA) and dicaffeoylquinic acids (diCQA) and some of their lactones were identified in the test samples of instant coffee. The components with m/z values of their deprotonated ions, which correspond to the coumaroylquinic, caffeoylferuloylquinic acids (CFQA) and some conjugates of cinnamic acid and tryptophan derivatives, were found. The content of 5-CQA, 3-CQA and caffeine in thirteen analyzed samples of instant coffee was determined and varied in the ranges of 3.4-11.6, 5.3-23.0 and 23.5-42.4 mg/g respectively. It was shown that the content of CGA in instant coffee can be an effective indicator of the quality of the product. Keywords : HPLC-UV-MS, isomers of chlorogenic acids, lactones of chlorogenic acids, caffeine, instant coffee DOI: http://dx.doi.org/10.15826/analitika.2017.21.3.008 E.A. Tishchenko, T.G. Tsiupko, V.V. Milevskaia, А .Z. Temerdashev Kuban State University, Stavropolskaia ul., 149, Krasnodar, 350040, Russia Federation