| Abstract [eng] |
Extra virgin olive oil (EVOO) is produced from the olive trees fruits (lot. Olea europeae), and due to the high content of monounsaturated fatty acids and other bioactive compounds, EVOO is considered beneficial for human health. Among other types of vegetable oils EVOOs are those with the highest content of compounds with bioactive properties. EVOO’s quality depends on various factors: degree of fruit ripeness, environmental conditions, growing region and techniques of processing and storage. Thus, pigments naturally degrade in oil during storage. The oxidation processes in olive oils are principally due to hydrolytic degradation, auto and photo oxidation. These processes mainly depend on fatty acid composition and on the presence of other bioactive components in EVOO. Components in EVOO such as phospholipids, carotenoids, tocopherols and chlorophylls can potentially act as anti- or pro-oxidants determining olive oil stability. Photosensitizers in EVOO are the main initiators of the light-induced oxidation, while the presence of antioxidants creates a protective effect. The purpose of this research was to investigate pigments in EVOOS, their aging processes and the effect of antioxidants on phototransformations. Four commercially available EVOOs was chosen for the experiments. While measuring absorption, fluorescence and excitation spectra of the specimens we have studied the phototransformations occurring while irradiating the samples with a light and also while monitoring aging process in EVOO. While studying fluorescence spectra of EVOO’s we have found that the irradiation of EVOO sample leads to the formation of hydroperoxides of unsaturated fatty acids. Which are responsible for the typical unpleasant aroma. |
