Determination of Triglyceride Composition of Tunisian and Sicilian virgin olive oil Using High Performance Liquid Chromatography and Evaporative Light Scattering Detection (HPLC-ELSD)

This work describes an HPLC procedure for the determination of triacylglycerol (TAG) profile of Tunisian and Sicilian monovarietal virgin olive oils. Sample preparation consisted in the dissolution of the oils in 2-propanol-acetonitrile-n-hexane. The chromatographic separation was achieved using a Luna™ C18 at room temperature and gradient elution with 2-propanol and acetonitrile. Elution was performed at a solvent flow rate of 0.7 mL/min. Detection was accomplished with an evaporative light scattering detector (ELSD), with the following settings: evaporator temperature 70 °C, nebulizer temperature 30°C and gas flow rate 1.0 SLM. Peak assignment was carried out by comparison with chromatograms reported in the literature. The linearity, precision and relative response of the method were examined. A total of 9 peaks were separated, identified, and quantified based on the relative percentage peak area. This methodology was applied to the two main Tunisian cultivars of olives (cvv. Chétoui of the North and Chémlali grown in the Centre and some regions of the South) and three principal Sicilian varieties (Nocellara del Belice, Biancolilla and Cerasuola) in order to compare its triacylglycerol (TAG) profile. The triglyceride profiles of Tunisian and Sicilian monovarietal virgin olive oils were elaborated by principal component analysis (PCA) considering the nine identified and quantified molecules. The explained variance from this PCA was higher than 61%.Hence results were satisfactory, because the method was able to discriminate successfully the most of Sicilian samples on basis of triolein amount (OOO). Moreover, Tunisian oils obtained from fourth and fifth olive harvest were especially influenced by theirs PLL, OLL and OOL contents.