Effect of cultivar and ripening on minor components in Spanish olive fruits and their corresponding virgin olive oils

Phenolics and volatiles are the compounds mainly responsible for the desirable flavour of extra virgin olive oils and therefore to a large extent determine the degree of consumer preference for this highly regarded product. The effect of both (i) the nature of the cultivar and (ii) the degree of ripening of the olive fruit on the biophenolic and volatile profiles of six different Spanish varieties (Arbequina, Cornicabra, Morisca, Picolimón, Picudo and Picual) and their corresponding virgin olive oils was determined in this study. A clear and statistically significant difference was observed for the oleuropein content, the main phenolic component found in the olive varieties studied. Demethyloleuropein was only found in the Arbequina variety and its content doubled during the ripening process. Verbascoside steadily increased throughout fruit maturation and cyanidin 3-O-rutinoside was the most abundant anthocyanin in all the varieties studied. Within the same cultivar a relationship between the oleosides content in the fruit and the presence of secoiridoids in the virgin olive oils was observed; however, the ratio between biophenols content in the olive fruit and in the virgin olive oil varied significantly for each of the cultivars studied (ranging from 2.3 for Picudo and 28 for Picolimon). The major volatile component was the C6 aldehyde fraction whose content varied greatly between the different varieties studied: E-2-hexenal content ranged from 20.5 mg of internal standard (4-methyl-2-pentanol) per kg of oil in the Arbequina variety to 3.1 mg/kg for Cornicabra; the amount of hexanal ranged from 1.75 mg/kg in Morisca to 0.70 mg/kg for Picual samples.