Discriminate analysis of roasted coffee varieties for trigonelline, nicotinic acid, and caffeine content.

Arabica and robusta roasted coffees from several geographical origins, in a total of 29 samples, were characterized for their contents in caffeine, trigonelline, and nicotinic acid by a recently developed HPLC/diode-array detector method. All samples were subjected to the same roasting procedure in order to eliminate the variations due to this process. Characterization was achieved by applying multivariate and nonparametric analysis to the chromatographic results. The two coffee varieties were clearly separated by their trigonelline and caffeine contents. Nicotinic acid could not be used as a variety discriminate factor. There was no association with the geographical origin of the samples.