Characterization of crude and purified pumpkin seed oil

Oil from hulled pumpkin seeds (Cucurbita pepo and Cucurbita maxima) was extracted with hot petroleum ether, and then it was degummed, neutralized and bleached, consecutively. Physical and chemical characteristics of crude and purified oils were determined. Density, refractive index, viscosity and peroxide value were not affected by purification, while decreases in acidity, colour, unsaponifiable, E-1cm(1%) 232, and oxidative stability, and increases in smoke point and E-1cm(1%) 270 were observed. Purification did not affect the fatty acid and sterol profiles. GLC analysis for the fatty acid composition of the seed oil showed that the predominant unsaturates were linoleic (42%) and oleic (38%), while the major saturates were palmitic (12,7%) and stearic (6%). Only a-tocopherol was detected at a level of 126 mg/kg, which reduced to 78 mg/kg after purification. The main sterols of pumpkin seed oil unsaponifiable were Delta(7,22,25), -stigmastatrien-3 beta-ol, a-spinasterol, Delta(7,25)-stigmastadienol and Delta(7)- avenasterol, followed by stigmasterol, 24-methylcholest-7-enol and Delta(7)-stigmastenol, and also trace to minor amounts of cholesterol, brassicasterol, campesterol, sitostanol, Delta(5)-avenasterol, erythrodiol and uvaol were found.