The influence of the olive variety and processing system on the sterol content in olive oil

U ovom radu su za ispitivanje korišteni uzorci maslinovog ulja proizvedeni iz plodova dviju domaćih sorti maslina s područja Dalmacije: Oblice kao najzastupljenije sorte (13 uzoraka) i Lastovke (6 uzoraka) čiji je uzgoj ograničen na područje otoka Korčule. Masline su ubrane sredinom studenog 2005. godine i prerađene prešanjem ili centrifugalnom ekstrakcijom. Osim osnovnih pokazatelja kvalitete (% slobodnih masnih kiselina, peroksidni broj i specifične apsorbancije u UV području) u ulju je određivan udjel i sastav sterola, eritrodiola i uvaola. Rezultati su pokazali da ulje iz Oblice ima puno više ukupnih sterola (1161 mg/kg -1902 mg/kg) od Lastovke (918 mg/kg -1301 mg/kg), dok ulje iz Lastovke ima veći udjel eritrodiola i uvaola (1.69 % - 2.59 %) od Oblice (0.23 % -1.24 %). Sorta ima statistički značajan utjecaj na udjel ∆7-kampesterola i β-sitosterola, a način prerade samo na udjel β-sitosterola.The investigations were carried out on the olive oil samples obtained from two domestic olive varieties from Dalmatia region: Oblica, the most representative Croatian variety (13 samples) and Lastovka (6 samples) which grows mostly at the Korcula island. Olives were harvested in the middle of November 2005. and processed by pressing or centrifugal extraction system. Beside the basic quality parameters (% of free fatty acids, peroxide value and specific UV absorbances) the content and composition of sterols as well as erythrodiol and uvaol in oil samples were determined. The results showed that oil from Oblica variety had higher amount of total sterols (1161 mg/kg – 1902 mg/kg) than oil from Lastovka (918 mg/kg – 1301 mg/kg), while oil from Lastovka had higher content of erythrodiol and uvaol (1,69 % – 2,59 %) than oil from Oblica (0,23 % – 1,24 %). The variety had statistically significant influence to Δ7 – campesterol and β – sitosterol content and processing system only to the content of β – sitosterol