Andalusian Protected Designations of Origin of Virgin Olive Oil: The Role of Chemical Composition in Their Authentication

Abstract

The latest regulation to protect unique virgin olive oils that have particular properties is called protected designations of origin (PDOs), and it has proven to be a successful way to protect quality and geographical authenticity. Nevertheless, sometimes the registration of new PDOs associated to new demarcations of geographic areas are almost based on administrative aspects rather than objective chemical data. In this study, the ability of chemical compounds of virgin olive oils with PDO is analyzed that are not labile and their concentrations do not vary over time − fatty acids, alcohols, hydrocarbons, methyl‐sterols and sterols − to differentiate them from those produced in their neighboring geographical areas. Three cases in the Andalusia region (Southern Spain) that combine pedoclimatic characteristics and variations of cultivar have been studied (9 areas with PDO and 3 non‐PDO areas). With a modified procedure of ANOVA analysis − the Brown–Forsythe test, chemical compounds that show good characteristics for the classification of samples are selected, and this ability is later checked by applying the unsupervised algorithm of Principal Component Analysis. Differences in their chemical composition are found when comparing the PDO oils with those produced in the neighboring olive tree groves despite chemical criteria are not among the most decisive factors for registering PDOs. Practical Applications: The practical application of this study is centered in the possibilities of the chemical composition of virgin olive oil being used to differentiate the PDO authenticity. The results of this study proves that it is difficult to establish discreet limits defining the PDO areas. The current physical‐chemical information should be used by both administration and PDO councils to supplement arguments for approving or denying new PDOs. Chemistry can assist the authenticity of virgin olive oil PDOs. The registration of new PDOs associated with new demarcations of geographic areas are almost based on administrative aspects rather than objective chemical data. In this work, chemical compounds that show good characteristics for the classification of samples are selected, and their classifying ability is later checked.