Study of the quality of virgin olive oil from Aragón (Spain)

The chemical composition of virgin olive oils (95 samples) from Aragón (Spain) from two successive crop seasons (1997/98 and 1998/99) and its relationship with quality and oxidative stability is examined. The main characteristics were: free acidity 0.5 (% oleic acid), peroxide value 11.8 meq/kg, K232 1.92, K270 0.13, oxidative stability 51.4 h (Rancimat method), and antioxidant phenolic substances 168.5 mg/kg (as caffeic acid). From the distribution of fatty acids, a high percentage of linoleic acid (9.46 %) and a low level of stearic (2.10 %) and arachidic (0.36 %) acids, is worth noting. The effect of sample origin (7 productive regions from Aragón), olive variety (Empeltre and Arbequina), and the different steps through processing are also investigated. However, the major factor affecting results was the plague of olive flies during 1997/98 crop season.