9.3.2 Compositional Changes due to Botanical
and Agronomical Factors
9.3.2.1 Variety
Many factors can influence VOO composition, including the agronomical practices
and extraction technology. The olive variety, or “cultivar”, the climatic conditions
and geographical location of the olive orchard and olive ripening degree influence
the final composition of the oil and therefore its flavour (Angerosa et al. 1999;
Malheiro et al. 2015; Kalogeropoulos and Kaliora 2015; García-González et al.
2010; Issaoui et al. 2009).
Olive cultivar is one of the most crucial factors responsible for olive oil flavour
variability (Tura et al. 2008). Virgin olive oil extracted in the same conditions can
show dramatic differences in its composition and sensory characteristics when
obtained from different varieties. Volatile compounds C6, especially trans-2hexenal, have been regarded as good indicators for differentiation of single-variety
olive oils. The olive variety also influences the concentration of phenolic compounds; the major influence has been attributed to the olive ripening degree and
environmental conditions (Škevin et al. 2003). At the same ripening degree,
cv. Coratina and Moraiolo were reported to show higher phenolic concentration
than other Italian varieties such as Leccino, Frantoio, Carolea and Ogliarola Barese
(Gucci et al. 2007). Dhifi et al. (2004) reported the concentration of aroma compounds in VOO extracted from four Tunisian olive cultivars Chetoui, Chemlali,
Chemchali and Oueslati. A wide range of differences was described depending on
the variety. Other researchers compared Tunisian cultivars with Italian ones,
reporting that cv. Chetoui is characterised by a low content of C6 aldehydes,
responsible for the sensory notes “green” and “fruity” (Baccouri et al. 2008).
According to Tura et al. (2008), the major volatile compounds affected by the
olive cultivars are the following: ethanol, 2-methyl propanol, pentanol, cis-2penten-1-ol, cis-3-hexenol and octanol. These compounds have been associated
with the following sensory notes, respectively: floral, banana, apple, walnut, hay,
butter, sweet and fruity.
9.3.2.2 Ripening Degree
The oil accumulation in the olive drupe starts about 5 weeks after anthesis, and its
major increase is between 60 and 120 days after flowering (Conde et al. 2008).
During the olive maturation phase, the fruit undergoes several modifications: the
exocarp colour changes from green to violet-black. A decrease in fruit consistency,
phenolic compound concentration and pigmentation takes place, with an increase of
free acidity.
The oil quality is strictly linked to the fruit physiological conditions, as the
progress of the ripening phase causes higher production of free fatty acids with a
9 Olive (Olea europaea)
223
and Agronomical Factors
9.3.2.1 Variety
Many factors can influence VOO composition, including the agronomical practices
and extraction technology. The olive variety, or “cultivar”, the climatic conditions
and geographical location of the olive orchard and olive ripening degree influence
the final composition of the oil and therefore its flavour (Angerosa et al. 1999;
Malheiro et al. 2015; Kalogeropoulos and Kaliora 2015; García-González et al.
2010; Issaoui et al. 2009).
Olive cultivar is one of the most crucial factors responsible for olive oil flavour
variability (Tura et al. 2008). Virgin olive oil extracted in the same conditions can
show dramatic differences in its composition and sensory characteristics when
obtained from different varieties. Volatile compounds C6, especially trans-2hexenal, have been regarded as good indicators for differentiation of single-variety
olive oils. The olive variety also influences the concentration of phenolic compounds; the major influence has been attributed to the olive ripening degree and
environmental conditions (Škevin et al. 2003). At the same ripening degree,
cv. Coratina and Moraiolo were reported to show higher phenolic concentration
than other Italian varieties such as Leccino, Frantoio, Carolea and Ogliarola Barese
(Gucci et al. 2007). Dhifi et al. (2004) reported the concentration of aroma compounds in VOO extracted from four Tunisian olive cultivars Chetoui, Chemlali,
Chemchali and Oueslati. A wide range of differences was described depending on
the variety. Other researchers compared Tunisian cultivars with Italian ones,
reporting that cv. Chetoui is characterised by a low content of C6 aldehydes,
responsible for the sensory notes “green” and “fruity” (Baccouri et al. 2008).
According to Tura et al. (2008), the major volatile compounds affected by the
olive cultivars are the following: ethanol, 2-methyl propanol, pentanol, cis-2penten-1-ol, cis-3-hexenol and octanol. These compounds have been associated
with the following sensory notes, respectively: floral, banana, apple, walnut, hay,
butter, sweet and fruity.
9.3.2.2 Ripening Degree
The oil accumulation in the olive drupe starts about 5 weeks after anthesis, and its
major increase is between 60 and 120 days after flowering (Conde et al. 2008).
During the olive maturation phase, the fruit undergoes several modifications: the
exocarp colour changes from green to violet-black. A decrease in fruit consistency,
phenolic compound concentration and pigmentation takes place, with an increase of
free acidity.
The oil quality is strictly linked to the fruit physiological conditions, as the
progress of the ripening phase causes higher production of free fatty acids with a
9 Olive (Olea europaea)
223