Dynamics of oil quality parameters changes related to olive fruit fly attack

In order to evaluate the role of intrinsic characteristics of olive cultivars on dynamics of oil quality parameters changes related to the olive fruit fly (Bactrocera oleae (Gmelin)) attack, two specific olive cultivars were compared, Istarska bjelica and Buža. I. bjelica is characterised by late ripening, a lower flesh/stone mass ratio and higher oleic/linoleic ratio, the total phenols content and oil mass fraction compared to Buža. Oil samples were obtained at two harvesting dates, from fruit lots with 0, 25, 50, 75 and 100% of infestation degree, expressed by mass. Oil and water content in olive paste, as well as total phenols, fatty acids composition and standard chemical and sensorial oil quality parameters were determined. At equal maturity level, the cultivar with a higher oil (24 ± 1% vs. 16 ± 1%) and lower water content (54 ± 2% vs. 61 ± 4%) was more susceptible to hydrolytic degradation, while the one with the lower total phenols content (231 ± 32 vs. 575 ± 124 mg/kg) and oleic/linoleic fatty acid ratio (5.7 vs. 9.1) was more liable to oxidative deterioration of oil. Lower susceptibility to negative flavours formation could be related to the absence of ripening induced by fly attack and less favourable environment for larvae growth (higher total phenols content, lower water content and flesh/stone mass ratio). Practical applications: Understanding the impact of olive fly attack is the basis of scientific and practical interest in the production of olives and olive oil. Different intrinsic characteristics of olive cultivars could lead to different susceptibility to oil quality deterioration caused by olive fly attack, which opens a possibility to adjust and minimise pesticide treatments. Knowledge about this topic could contribute to the reduction of costs of olive pests control, as well as to the improvement of quality and food safety concept in olive oil production.