Changes in the phenolic compounds composition of virgin olive Oil due to different storage conditions under accelerated ageing

Virgin olive oil is well known for its high amount of antioxidant phenolic compounds, such as hydroxytyrosol or oleocanthal [1], and their protective effects against cancer, coronary heart diseases and ageing by inhibiting oxidative stress [2]. The composition of these compounds depends on various parameters, the variety, environmental conditions, ripeness degree and the extraction type and storage [3]. We have special interest in the long term stability of these compounds and their concentration changes during storage after bottling.

For this purpose the oil is bottled in different kind of glasses and exposed to light under monitored and recorded circumstances, to induce accelerated aging. After defined periods olive oil samples are taken and their phenolic compositions are analyzed. Next to the phenolic compounds, the free fatty acids, the peroxide values and the aliphatic alcohol contents are determined according to Pharmacopeia Europea, in order to classify the oil quality.

Within this approach, different types of solid phase extraction (SPE) materials are compared to each other. The focus lays on the different properties of silica based and polymeric based materials in regard to their applications for phenolic compounds. These materials are partly commercial available and partly self synthesised and functionalised [4]. Due to this work, a greater insight is gained for the adulteration of olive oils and its health supporting components. Furthermore, a good way for the optimisations of phenolic analyses in complex biological matrices is shown by synthesising and functionalising of SPE materials.

References: 1. Beauchamp, G. et al. (2005), Nature 437: 45–46. 2. Owen, R. et al. (2000), Eur. J. Cancer 36: 1235–1247. 3. Owen, R. et al. (2000), Food Chem. Tox. 38: 647–659. 4. Sultan, M., Stecher, G. et al. (2005), Curr. Med. Chem. 12: 573–588.