How extraction method affects yield, fatty acids composition and bioactive properties of cardoon seed oil?

Cardoon (Cynara cardunculus L.; Asteraceae) is a perennial species with several uses, especially in the industry of energy production, while it is classified as a non-conventional energy crop within the European Union (EU). The aim of the present study was to evaluate chemical composition and antioxidant properties of cardoon seed oils extracted with two mechanical pressing methods, while at the same time it further determined composition and antioxidant properties of the obtained seedcakes. Oil extraction yield did not differ between the tested methods and growing years, indicating that both heat and cold extraction are efficient methods for oil production (approx. 75% extraction yield). Oils obtained from heat extraction method had better antioxidant properties than cold pressed oils, while significant variation between the growing years was also observed. Seedcakes of heat extraction method had the highest total phenols (405 mg Gallic acid equivalents (GAE)/g extract) and the highest antioxidant properties for all the tested assays (with the exception of reducing power assay). Moreover, none of the studied materials (seeds, seed oils, and seedcakes) showed toxicity effects against PLP2 non-tumor cells (GI50 > 400 μg/mL). The main fatty acids were linoleic and oleic acids which were detected in similar amounts in oils and seedcakes, while significant variation was observed between the tested methods and the growing years. The results of the present study signified the importance of cardoon as an alternative field crop under the Mediterranean climate conditions. In addition, seed oil production byproducts (e.g. seedcakes) are a promising material due to its bioactivities and its fat content and fatty acid composition, that could find alternative uses in the pharmaceutical and cosmetics industry.