Variance of elemental concentrations of organic products : the case of Brazilian coffee

Elemental composition can be used to help determining the origin and quality of food and beverage. The present study aims to investigate the variation of the elemental composition of a Brazilian coffee brand across different production batches. To that end, 102 samples from 11 different batches of “Melitta Tradicional” roasted ground coffee were analyzed using the Particle-Induced X-ray Emission (PIXE) technique. The concentrations of Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn and Rb were determined. Differences in the elemental concentrations between at least two batches were observed for all investigated elements but Ti. For elements such as Cl, Ca, Cu and Rb the concentration varied over 50% between batches. The differences observed among batches indicate that the characterization of coffee by brand or origin is not a straightforward task.