CONICET | Buscador de Institutos y Recursos Humanos

The production and consumption of olive oil is increasing due to the characteristic flavor and for its nutritional qualities. Natural antioxidants such as essential oils from aromatic plants can be added to food in order to substitute artificial ones. The objective of this work was to evaluate the preservation effect of Argentinean oregano essential oils on chemical quality parameter of extra virgin olive oil. Essential oils from four different species of Origanum: Mendocino (Men), Compacto (Com), Cordobés (Cor) and Criollo (Crio) were added at 0.05%w/w to olive oil. Chemical composition of the essential oils was determined by CG-MS. Different treatments were carried out: olive oils with essential oils (Men, Com, Cor and Crio) and without (C) were exposed to light (L) and darkness (D) at room temperature. They were storage for 84 days. Every 21 days, samples were removed and analyzed for: a) peroxide value, b) free fatty acids, c) chlorophylls and carotenoid contents, d) conjugate dienes and trienes and f) p-ansidine value. Olive oil fatty acid composition was also determined by GC-MS. After 84 storage days, all chemical parameter changed decreasing the quality of olive oil. The peroxide value in C-L (light) increased to 48 meqO2/ kg. The lowest peroxide value (13.29 meqO2/kg) was observed in Crio-D (darkness). Chlorophyll and carotenoid content highly decreased in light exposure. However, these treatments in D had the highest values for chlorophyll (1,38mg/kg in Crio-D) and carotenoids (3,42mg/kg in Com-D) contents. Substantial differences were observed between treatments with or without light exposure and between oregano essential oils. Crio and Com essential oil showed higher thymol content and better preservation quality. The addition of oregano essential oils to Olive oil increases its self-life during storage preserving the chemical quality parameter. This study has a positive impact for both food products