Browsing by Author "Jaatinen, Jussi"

Olive oil is one of the most thoroughly analyzed vegetable oils. A lot of research has been done to examine the health effects of the consumption of olive oil. Also the authenticity of olive oil has been of major concern and has led to numerous research projects and investigation. The EU Commission´s regulation No. 1348/2013 determines the maximum acceptable levels of several components in all categories of olive oil. The most significant differences between refined olive oil and non-refined extra virgin olive oil (EVOO) appear to be in the natural UV-absorption at wavelength 270 nm and in stigmastadiene concentration, consequently, also in the maximum accepted levels of these two parameters. Cheaper refined olive oil and other vegetable oils are produced on a large scale which raises the risk of adulteration by cutting more valuable EVOO with refined vegetable oils. To detect the mixing of EVOO with refined vegetable oils, measuring the K₂₇₀-value and determining the stigmastadiene concentration seem to be very efficient methods. Both UV-absorption at wavelength 270 nm and the concentration of stigmastadiene appear to rise during the refining processes of lower class virgin oil (lampante) and also when refining vegetable oils. The aim of this master´s thesis work was to compare different methods and possible natural marker compounds in detecting the addition of refined vegetable oil in extra virgin olive oil. A thorough research was done to investigate the effects of mixing ordinary olive oil (OO), which consists of refined olive oils and virgin olive oils, with EVOO. Also mixtures of refined sunflower oil and EVOO were analyzed. The mixtures were then analyzed with GC-MS to determine the concentration of stigmastadiene. As the result, a mixture of 15–30 % of refined oil to EVOO raised the K₂₇₀-value above the regulation´s maximum accepted level of 0.22. Mixtures of 5 % of refined oil to EVOO raised the stigmastadiene concentration to levels of 0.09–0.27 mg kg⁻¹, thus clearly above the regulation´s maximum accepted level of 0.05 mg kg⁻¹. Both methods are relatively fast and non-laborious. They can be used as a combination to screen oils in order to detect possible adulteration and to proceed to further investigation when necessary.