The characterization and classification of Tuscan olive oils by zone: yearly variations of the oil composition and reliability of the classification models

In order to study and classify Tuscan virgin olive oils, 179 samples were collected. They were obtained from drupes harvested during the first half of November, from three different zones of the Region. The sampling was repeated for 5 years. Sensory and chemical analyses were carried out. Fatty acids, Phytol, aliphatic and triterpenic alcohols, triterpenic dialcohols, sterols, Squalene and tocopherols were analyzed. Two zones at a time were considered. The most effective and reliable variable to be included in multivariate classification models were selected. The best performing model to classify oils from the N and E zones, includes four variables: Cycloartenol, Phytol, "Calculated Grade" and "Fruity". The best N-vs.-W model includes Palmitoleic acid, Cycloartenol, and a minor polar compound whose identification is still in progress. The best E-vs.-W model is univariate and includes only Palmitic acid.