Within our masters paper we determined the influence of a species of hazel (Corylus Avellana) and the temperature of oil pressing on the physical and chemical properties of hazelnut oil. We measured the value of the fatty acid composition, free fatty acids, peroxide number, p-anisidine value, Totox value, antioxidant potential, the content of conjugated dieness and trienes, dielectric constant and the factor of dielectric losses. We analyzed the oils of five different types of hazel. One sample contained the mixture of different sorts of oil, while three samples were procured pressed at different temperatures. The analyzed oils consist largely of oleic fatty acid (72,8 g/(100 g)) and linoleic fatty acid (9,4 g/(100 g)). All the analyzed oils had the allowed content of free fatty acids and a peroxide number. P anisidine value was elevated at all samples, the value drew close to, or exceeded the recommended value of 2. Next to nine samples of oil, we analyzed the content of fats and water in the hazelnuts of the subspicies Isterska dolgoplodna. We pressed the pomace of this strain at the temperatures of 30, 40 and 50 °C. A hazelnut of this strain contains 61% fats,. With every increase of the temperature by 10 °C (up to 50 °C), we gain an additional 2 (kg oil)/(100 kg hazelnuts), and doing so we do not alter the antioxidant potential. In the oil, gained when pressing at 50 °C, the peroxide number inceases (by 70%). The oil gained at 50 °C contained slightly more conjugated dienovs and more conjugated trienes.The temperature of pressing oil influences on the increased value of the dielectric constant, the factor of dielectric losses, electrical conductivity and the content of polyunsaturated fatty acids. The latter of which are 5% less at oil pressed at 50 °C, that only testifies to the temperature instability of polyunsaturated fatty acids.
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