Pattern recognition of cardoon oil from different large-scale field trials

Abstract

Cardoon (Cynara cardunculus L.) is a spontaneous perennial thistle well adapted to the Mediterranean region, classified as a non-conventional energy crop by the EU. Large-scale field trials, using commercial grains of the same genotype, were installed for the first time in two fields in Portugal: Beja (77.4 ha) and Sesimbra (8.1 ha). In this study, the oil was extracted from composite seed samples and analysed in terms of fatty acid, triacylglycerol (TAG), sterol and tocopherol compositions. The oil content was 24.3% and 23.2% (dry basis) for samples from Beja and Sesimbra. Pattern recognition techniques (Principal Component Analysis and hierarchical Cluster Analysis) were used for sample characterization. Sample origin was correctly identified when (i) TAG profile or (ii) tocopherols and sterols compositions (bioactive compounds) were used. Sesimbra oils showed higher contents of the TAG LLL and PLL, while Beja oils presented higher amounts of OLL, OOL, OOO and POO. Sesimbra oils are richer in linoleic acid (63.7% vs. 59.5% in Beja) while Beja oils are richer in oleic acid (24.5% vs. 20.9% in Sesimbra). β-sitosterol (30.9% in Beja vs. 31.5% in Sesimbra) and Δ7-stigmastenol (31.3% in Beja vs. 30.5% in Sesimbra oils) are the major sterols. Alpha-tocopherol (111.6 mg/kg in Beja vs. 222.4 mg/kg in Sesimbra samples) was the dominant tocopherol. Sesimbra oils showed higher contents of bioactive compounds and therefore, higher biological value than oils from Beja. The environmental conditions showed to be more important on cardoon oil composition than the genetic variability.