Qualitative Changes of Olive Oils Obtained from Fruits Damaged by Bactrocera oleae (Rossi)

Abstract

<jats:p>Mature fruits of <jats:italic>Olea europaea</jats:italic> L. ‘Frantoio’ with different degrees of damage [from 0% to 100% of fruits with exit holes (EHs)] caused by the olive fruit fly (<jats:italic>Bactrocera oleae</jats:italic>), the key pest in Mediterranean olive orchards, were sampled to quantify the effects on free acidity, peroxide value (PV), and concentrations of secoiridoids and lignans of virgin olive oil (VOO). The total concentration of phenolic compounds and that of individual secoiridoids were negatively related to the degree of fruit damage, whereas the concentration of lignans, namely (+)-pinoresinol and (+)-1-acetoxypinoresinol, was unaffected. Free acidity was similar for the 0% and 10% EH treatments, increased sharply between 10% and 30% EH, and was similar again for the 60% and 100% EH treatments. Free acidity values were low and well within the limit for VOO classification even after 6 months of oil storage. Peroxide value responded to both <jats:italic>B. oleae</jats:italic> damage and storage conditions. Peroxide values increased between 10% and 30% EH treatments but changed little between the 30% and 100% EH treatments regardless of oil storage conditions. Secoiridoid concentrations closely reflected the degree of <jats:italic>B. oleae</jats:italic> damage when sources of variability such as cultivar and cultural practices were kept under control and conditions of processing and oil storage were optimal.</jats:p>

Irrigation and fruit canopy position modify oil quality of olive trees (cv. Frantoio)

“…Oil was extracted from approximately 1.5 kg of fruits sampled from each canopy position of each tree using an Abencor system (MC2, Ingenieria y Systemas, Sevilla, Spain) within 24 h of harvest . From each sample, we obtained approximately 100 mL of oil, which was then stored in the dark at 14 °C until analyses.…”

“…From each sample, we obtained approximately 100 mL of oil, which was then stored in the dark at 14 °C until analyses. Free acidity and the peroxide value of oils were determined colorimetrically using an Oxitester unit (Olive Oxytester; CDR, Ginestra Fiorentina, FI, Italy) that allowed the determination of both parameters rapidly on small samples . Fatty acid composition and ultraviolet absorption characteristics at 232 and 270 nm of oils were measured in accordance with European Official Methods …”

Effect of fruit volatiles and light intensity on the reproduction of Bactrocera (Dacus) oleae

“…The damage caused by the olive fly consists in fruit deterioration caused by oviposition stings and larval feeding in the mesocarp (Tzanakakis ), premature fruit drop (Neuenschwander and Michelakis ) and oil quality deterioration (Gucci et al. ). Females lay their eggs in the mesocarp of olive fruit, and the larvae feed on and destroy it before pupating in the soil.…”

Feasibility of NIR spectroscopy to detect olive fruit infested by Bactrocera oleae

“…In fact, phenolic content has been reported to decrease as a consequence of the olive fruit fly attack (Gómez-Caravaca et al, 2008;Tamendjari et al, 2009). Highly infested olives generally exhibit a strong increase in peroxide value (Pereira et al, 2004;Gucci et al, 2012).…”

“…Moreover, the infested olives produce oil with a reduced content of antioxidant phenolics (Gómez-Caravaca et al, 2008;Gucci et al, 2012) and an altered volatile compound profile (Angerosa et al, 2004) leading to severe and unacceptable off-flavour. Consequently, the nutritional value and the sensory properties of oil extracted from infested olives are compromised, http://dx.doi.org/10.1016/j.postharvbio.2014.07.015 0925-5214/© 2014 Elsevier B.V. All rights reserved.…”