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The presence of food in extra virgin olive oil (EVOO) during simultaneous storage might bring additional changes to the oil’s composition and quality. To investigate this matter, the influence of dried tomatoes on the oxidative and hydrolytic parameters, fatty acids, phenolic and volatile composition, antioxidant activity, pigments, and sensory attributes of EVOO during six months of simultaneous storage at room temperature (RT; 22 ± 2 °C) and +4 °C, was studied. Lower storage temperature reduced the hydrolytic and oxidative degradation of oils when dried tomatoes were immersed. The dried tomatoes addition did not affect the fatty acids composition of EVOO. The accelerated degradation kinetics of individual phenolic compounds and antioxidant activity of oils were influenced by the presence of dried tomatoes, being more pronounced at RT. C6 and C5 volatiles responsible for the green odour of EVOO decreased, while tomato-derived volatiles (3-methylbutanal and acetic acid) increased during simultaneous storage with dried tomatoes, especially at RT. The addition of dried tomatoes diminished the intensities of EVOO’s positive attributes (fruitiness, bitterness, and pungency) while enhancing the tomato odour attribute. This study demonstrates that the introduction of dried tomatoes significantly alters the composition and quality of EVOO when used as a storage medium.

In the present study, the influence of heating on the evolution of oxidative indices, antioxidant activity, phenolic and volatile compounds in monovarietal extra virgin olive oils (EVOOs) obtained from Leccino, Istarska bjelica, and Buža cultivars was investigated. The samples were submitted to heating in an air oven (180 °C and 220 °C), simulating usual roasting conditions typical for Mediterranean cuisine. The decreases in the oxidative indicators, phenolic and volatile compounds were more pronounced at higher heating temperatures, underlining the temperature dependency of the oxidative degradation during heating conditions. Despite this, it must be emphasized that a significant amount of phenolic compounds and antioxidative activity remained preserved after the heating treatment. Each oil cultivar showed some specificity during the course of the thermal degradation. Hydroxytyrosol acetate among phenolic compounds and octanal, (E)-2-octenal, hexanal, 3-pentanone, and 1-penten-3-one among the volatiles were underlined as possible markers of thermal oxidation. Principal component analysis revealed that the content of volatile compounds in monovarietal EVOO samples distinguished samples primarily by the heating temperature, while the changes in the phenolic compounds were cultivar-dependent aside from being influenced by the temperature of heating.

The possibility of enriching the oil produced from Leccino cultivar olive fruits with phenolic and volatile compounds by adding olive leaves (2.5%) during industrial-scale production were investigated. Furthermore, the influence of the addition of leaves on the oil quality, composition, and oxidative stability during storage for 6 and 12 months was studied. A slight negative impact on the oil quality after processing with leaves was determined. The addition of leaves had no influence on the total saturated, monounsaturated, and polyunsaturated fatty acids in oils, while it influenced increases in total phenolic compounds (+29.55%), total secoiridoids (+29.43%), chlorophylls (+47.59%), and the oil stability index (+18.70%), and their higher values were also determined in the stored oils. The addition of leaves increased C5 volatiles (+10.50%) but decreased C6 volatiles (−10.48%). The intensity of most of the positive sensory characteristics increased in fresh oils obtained with leaves, and the established improvements were also maintained in the stored oils. The extractability of olive paste was positively affected by the addition of olive leaves, which increased the oil yield (+27.17%). The obtained results significantly contribute to the knowledge about the possibilities of enriching olive oils with bioactive compounds.

Croatian islands are olive growing areas characterized by poor conditions for olive trees because of karst soil and a precipitation deficiency. Under these conditions, irrigation is a very important factor for constant olive oil production. This paper aims to investigate the effects of different watering regimes on quantity, sensory and chemical quality and composition of Coratina cv. olive oil obtained from trees grown on ameliorate karst soil during two harvesting years. Olive trees were subjected to rainfed conditions and three different irrigation treatments (T1—deficit irrigation representing the usual producer’s practice, T2—regulated deficit irrigation in respect to phenological stages, T3—full irrigation). Irrigation treatments increased oil yield compared to rainfed conditions (T1 + 58%, T2 + 66% and T3 + 74%, representing average values for both studied years). All olive oil samples were of extra quality. Irrigation led to a decrease in carotenoids, volatiles, polyunsaturated fatty acids and linolenic acid contents, with no difference found among irrigation treatments. Total phenols and secoiridoids concentration was not affected by irrigation, indicating that similar oil quality could be achieved with less demand on the water supply. Obtained results could help producers to define a suitable irrigation management in particular conditions of ameliorate karst.