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Influence of olive fruit fly attack on quality and composition of Rosinjola cv. virgin olive oil

In this work the influence of olive fruit fly (Bactrocera oleae (Rossi)) attack on the quality of ´Rosinjola’ cv. virgin olive oil (free fatty acids, peroxide value, specific extinction on 232 and 270 nm, and sensory evaluation) as well as on the fatty acid and volatile composition was investigated. Therefore, olive fruits were collected and divided into two groups according to the presence (infested - 100%) or absence of infestation (healthy - 0%) by the olive fruit fly, and the third group was made by mixing two previously described groups in equal proportions (infested - 50%). Each group of olive fruits was separately processed under the same conditions to produce corresponding virgin olive oils. The results of oil acidity, signs of hydrolytic degradation of olive oils, showed that olive fruit fly infestation at the 50% and 100% level significantly reduced the quality of oil. Sensory score and intensity of positive sensory characteristics of the investigated oils decreased by the increase of fruit fly infestation level, but the occurrence of defects in oils as a consequence of fruit fly attack was not detected. Considering the fatty acid composition, olive fly attack caused only a slight reduction of palmitic acid. Volatile profile of investigated olive oils showed that olive fly attack influenced a decrease of total C6 volatiles (a decrease of C6 aldehydes, but an increase of C6 alcohols) and an increase of total C5 volatiles. The results confirmed the importance of healthy fruit in obtaining high quality virgin olive oil, but despite the olive fruit fly attack ´Rosinjola’ oil still maintained extra virgin olive oil category according to market quality parameters.

Bactrocera oleae; olive oil; quality; sensory characteristics; fatty acids; volatile compounds

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