A First Description of the Phenolic Profile of EVOOs from the Maltese Islands Using SPE and HPLC: Pedo-Climatic Conditions Modulate Genetic Factors

Abstract

Achieving economic sustainability in the olive oil production sector is a challenge. This is particularly so for small scale producers who are faced with pressing, production and marketing costs that relative to overall sales, minimise profits. In this study we aimed to describe the phenolic profile of extra virgin olive oils (EVOOs) derived from the Maltese islands. The polar fractions from EVOOs from nine indigenous (six Bidni and three Malti), one historically acclimatized tree (Bajda), 12 locally-grown but foreign cultivars and 32 foreign EVOOs were extracted using SPE (solid phase extraction), separated using HPLC analysis at 280 nm and 320 nm and identified using mass spectrometry. Application of ANOVA and Tukey post hoc hypothesis testing for analysis of variance on the peak areas identified a significantly higher concentration of p-coumaric acid, tyrosol acetate, DHPEA-EDA and oleocanthal in EVOOs derived from indigenous or historically acclimatized cultivars. Imported but locally grown cultivars showed differences when compared to the same cultivar grown in other countries, confirming that pedo-climatic conditions modulate genetic factors.

The First Identification of the Uniqueness and Authentication of Maltese Extra Virgin Olive Oil Using 3D-Fluorescence Spectroscopy Coupled with Multi-Way Data Analysis

“…Whilst the 'Bidni' and 'Bajda' are monocultivars, the 'Malti' is thought to be made up of several ancient varieties which are geographically isolated from each other [22]. Furthermore, recent studies have shown that Maltese EVOOs have a significantly different phenolic composition and mineral composition [23,24]. In this study, a variety of olive oils selected from different areas around the Maltese islands and countries around the Mediterranean were studied.…”

Conservation of Native Wild Ivory-White Olives from the MEDES Islands Natural Reserve to Maintain Virgin Olive Oil Diversity

“…The high content of MUFA, particularly the oleic acid, and phenolic compounds can protect the oil to oxidation [ 35 ]. Similar ivory-white cultivars (Leucocarpa and Bajda) had been previously studied without reporting the fatty acid profile [ 13 , 14 , 16 ].…”

“…To date, there is little information on the phenolic profile of virgin olive of ivory-white olives. In a previous study carried out with Bajda cultivar, oleacein, oleocanthal, oleuropein aglycone, and ligstroside aglycone were only identified but not quantified [ 16 ]. Leucocarpa cultivar also was analyzed and low concentrations of oleuropein aglycone were detected in the fruit (6.63 ± 0.22 to 16.8 ± 0.07 mg/g of fresh weight) whereas other compounds were not analyzed [ 13 ].…”

“…The hydroxytyrosol, an essential quality biomarker in virgin olive oil, was also identified in olive samples (0.77 ± 0.57 mg/kg). This phenolic alcohol was also identified in olive oil from ivory-whites [ 16 ]. The variations in the phenolic alcohols is also attributed to ripening and varietal factors [ 57 ].…”

“…The presence of a few wild olive trees which produce ivory-white fruits has been observed in prospecting surveys in Spain (Belaj A, unpublished results) but up to now no further attention has been paid to their study. In this sense, to the best of our knowledge, the only cultivated genotypes with ivory-white fruits are Leucocarpa in Italy [ 13 , 14 ], Marfil in Spain [ 15 ], and Bajda in the Maltese islands [ 16 ].…”