parallel decrease of the bitter note linked to the phenolic compounds (Garcia, Seller
and Perez-Camino 1996).
Olive maturity degree also influences the generation of aroma compounds. The
maximum concentration is observed when the colour changing phase starts in the
fruit.
It is known that at higher ripening stages, the aromatic note described as “fruitygrassy” is significantly lower than in oils obtained from greener olives. The sensory
notes of bitter-pungent and other positive aromatic notes decrease with increasing
ripening degree. The increase in olive maturity leads to the increase in 1-penten-3-ol
content. The compounds hexanal, trans-3-hexenol, cis-3-hexen-1-ol and cis-2hexenol were reported to have high selectivity for unripe olives. The intermediate
maturation phase was characterised using hexyl acetate, while overripe drupes can
be discriminated using trans-3-hexenal, cis-2-hexenal, trans-3-hexenol and cis-3hexenol (Aparicio and Morales 1998).
Some triterpenic alcohols were proposed as markers of fruit maturity. Sakouhi
et al. (2009) demonstrated that triterpenic alcohols and 4-monomethyl sterol concentrations in the olive fruit increase from 18% to 30% during ripening of the
cv. Picholine.
A negative correlation (R
2
¼ À0.88) between the drupe ripening degree and
phenolic content in VOO was also reported by Rotondi et al. (2004). Gomez-Rico
et al. (2006) studied the combined effect of maturity and irrigation on the phenolic
and volatile compounds of VOOs obtained from cv. Cornicabra, showing a significant loss of the most complex phenolic compounds, also linked to the irrigation
conditions in the field.
During drupe maturation, an increase of the triterpenic alcohol 24-methylenecycloartenol has been reported. In addition, sterols undergo significant changes,
e.g. increasing of Δ5-avenasterol and decreasing of β-sitosterol (Luna 2002).
Tura et al. (2008) reported the importance of the maturity degree on the content of
phenolic and volatile compounds, but fruit storage can also result in a change of the
flavour profile, due to the lowering of esters and aldehydes responsible for the
positive notes (Kalua et al. 2007).
Longer storage of the olive fruits and increased ripening degree lead to a decrease
of the content of volatile compounds, particularly those responsible for the sensory
notes of fruity, almond, green (trans-2-hexenal, hexanal, cis-3-esenolo) and sweet
(1-penten-3-one, 3-pentanone), with a contemporary increase of some alcohols
(3-methyl-1-butanol, 2-methyl-1-propanol).
The olive fly (Bactrocera oleae) is the most important biotic stress factor affecting the drupe quality. VOO produced from fruits attacked by the olive fly has higher
free acidity and peroxide number and different fatty acid composition and concentration of phenolic compounds (Gomez-Caravaca et al. 2008). Significant differences from the sensory panel of these oils have also been reported (Angerosa et al.
1992). The sensory profile of such VOOs has lower scores when the olives are
harvested at full maturity stage, characterised by an increase of negative sensory
notes such as fusty, mouldy and winey-vinegary. Olive fly attack causes a significant
decrease of the attribute “pungent-bitter” (Tamendjari et al. 2009).
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N. Caporaso and D. Boskou
and Perez-Camino 1996).
Olive maturity degree also influences the generation of aroma compounds. The
maximum concentration is observed when the colour changing phase starts in the
fruit.
It is known that at higher ripening stages, the aromatic note described as “fruitygrassy” is significantly lower than in oils obtained from greener olives. The sensory
notes of bitter-pungent and other positive aromatic notes decrease with increasing
ripening degree. The increase in olive maturity leads to the increase in 1-penten-3-ol
content. The compounds hexanal, trans-3-hexenol, cis-3-hexen-1-ol and cis-2hexenol were reported to have high selectivity for unripe olives. The intermediate
maturation phase was characterised using hexyl acetate, while overripe drupes can
be discriminated using trans-3-hexenal, cis-2-hexenal, trans-3-hexenol and cis-3hexenol (Aparicio and Morales 1998).
Some triterpenic alcohols were proposed as markers of fruit maturity. Sakouhi
et al. (2009) demonstrated that triterpenic alcohols and 4-monomethyl sterol concentrations in the olive fruit increase from 18% to 30% during ripening of the
cv. Picholine.
A negative correlation (R
2
¼ À0.88) between the drupe ripening degree and
phenolic content in VOO was also reported by Rotondi et al. (2004). Gomez-Rico
et al. (2006) studied the combined effect of maturity and irrigation on the phenolic
and volatile compounds of VOOs obtained from cv. Cornicabra, showing a significant loss of the most complex phenolic compounds, also linked to the irrigation
conditions in the field.
During drupe maturation, an increase of the triterpenic alcohol 24-methylenecycloartenol has been reported. In addition, sterols undergo significant changes,
e.g. increasing of Δ5-avenasterol and decreasing of β-sitosterol (Luna 2002).
Tura et al. (2008) reported the importance of the maturity degree on the content of
phenolic and volatile compounds, but fruit storage can also result in a change of the
flavour profile, due to the lowering of esters and aldehydes responsible for the
positive notes (Kalua et al. 2007).
Longer storage of the olive fruits and increased ripening degree lead to a decrease
of the content of volatile compounds, particularly those responsible for the sensory
notes of fruity, almond, green (trans-2-hexenal, hexanal, cis-3-esenolo) and sweet
(1-penten-3-one, 3-pentanone), with a contemporary increase of some alcohols
(3-methyl-1-butanol, 2-methyl-1-propanol).
The olive fly (Bactrocera oleae) is the most important biotic stress factor affecting the drupe quality. VOO produced from fruits attacked by the olive fly has higher
free acidity and peroxide number and different fatty acid composition and concentration of phenolic compounds (Gomez-Caravaca et al. 2008). Significant differences from the sensory panel of these oils have also been reported (Angerosa et al.
1992). The sensory profile of such VOOs has lower scores when the olives are
harvested at full maturity stage, characterised by an increase of negative sensory
notes such as fusty, mouldy and winey-vinegary. Olive fly attack causes a significant
decrease of the attribute “pungent-bitter” (Tamendjari et al. 2009).
224
N. Caporaso and D. Boskou