Chemical characterization of organic and non-organic virgin olive oils

Organic food products have shown to have lower environmental impact and lower presence of chemical residues. Consumers generally have positive attitudes towards organic food because of superior taste, environment- friendliness, health, food safety and animal welfare. During last years, the demand of consumers for organic virgin olive oils have been increased as a result of their high quality image from nutritional and health aspects. In this work sixteen virgin olive oil samples, four obtained by organic and twelve from non-organic cultivation, were analysed by their quality parameters (acidity, peroxide value and UV absorption), fatty acids, sterols and volatile compounds. Qual- ity parameters were not able to discriminate between organic and non-organic samples although significant differences were found in the values of acidity and K270. Fatty acids and sterols content were able to discriminate samples ac- cording to their cultivar but did not show capacity differentiating the samples according to the cultivation system. The results of volatile analysis show that in general terms the organic virgin olive oils showed a higher concentration of volatile compounds, except for the aldehydes, whose concentration was higher in the non-organic oils, and the acids, whose concentration was similar in the both oil classes. The concentration of ketones, aldehydes, and alcohols showed significant variations (p < 0.05) between the two types of oils.