Antioxidant Activity and other Quality Parameters of Cold Pressing Pumpkin Seed Oil

Abstract

Pumpkin seeds oil are rich in biologically active substances such as a source of tocopherols, carotenoids, especially β-carotene, lutein and other compounds. Also four fatty acids – palmitic, stearic, oleic and linoleic, dominated in the oil of pumpkin seeds oil. The study mainly aimed to evaluate the fatty acid contents and antioxidant parameters of seed oils isolated from different pumpkin cultivars. Investigations of seeds oil from Cucurbita pepo L. ‘Miranda’, ‘Golosemianaja’, and ‘Herakles’ pumpkin cultivars grown in Lithuania revealed that crude fat contents ranged from 44.4% to 47.3%, although ‘Miranda’ cultivar seeds consistently and significantly had the lowest content. The seed oils contained appreciable amounts of unsaturated fatty acids (approximately 83%), of which polyunsaturated fatty acids, particularly palmitic, stearic, oleic and linoleic acids, were dominant with values ranging from 64.29% to 66.71% of the total amount of fatty acids. The seeds oil were a particularly rich source of linoleic acid (66%), among which ‘Miranda’ cultivar seeds had the significantly highest content. Our investigation identified that pumpkin seeds oil as a good source of phenolic compounds, particularly cvs. ‘Golosemianaja’ and ‘Miranda’ oil. Methanolic seed oil extracts were characterized by statistically significant differences in their antioxidant activity, with the highest antioxidant activity found in cultivar ‘Miranda’, followed by ‘Golosemianaja’. The antioxidant activity level increased proportionally with the total phenolic content, thus establishing a linear relationship between DPPH-radical scavenging activity and total phenolic content.