Combined use of total metal content and size fractionation of metal biomolecules to determine the provenance of pine nuts (Pinus pinea

Abstract

Four essential elements (Mn, Ni, Zn, and Cu) and their molecular-size distribution patterns have been determined, for twenty four samples of pine nuts from eight areas in Spain and Portugal (Huelva, Cádiz, Badajoz, Cataluña, Castilla, Madrid, Faro, and Coimbra), by sizeexclusion liquid chromatography (SEC) coupled on-line to UV and inductively coupled plasma mass spectrometric (ICP–MS) detection. The variability observed in total element content and the size-exclusion profiles of elements in samples from distant areas were considered as chemical descriptors for characterization of geographic origin. A pattern-recognition technique, the display method principal component analysis, was used as visualization technique to determine the provenance of the pine nuts collected. The results obtained confirmed that size fractionation profiles give more information for assessing the provenance of pine nuts than the total elements composition traditionally used for this purpose. Combination of these chemical descriptors was the most suitable choice for the samples studied.