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 AE 1% vs. 16 AE 1%) and lower water content (54 AE 2% vs. 61 AE 4%) was more susceptible to hydrolytic degradation, while the one with the lower total phenols content (231 AE 32 vs. 575 AE 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.

In this work, fatty-acid profiles, including trans fatty acids, in combination with chemometric tools, were applied as a determinant of purity (i.e., adulteration) and provenance (i.e., geographical origin) of cosmetic grade argan oil collected from different regions of Morocco in 2017. The fatty acid profiles obtained by gas chromatography (GC) showed that oleic acid (C18:1) is the most abundant fatty acid, followed by linoleic acid (C18:2) and palmitic acid (C16:0). The content of trans-oleic and trans-linoleic isomers was between 0.02% and 0.03%, while trans-linolenic isomers were between 0.06% and 0.09%. Discriminant analysis (DA) and orthogonal projection to latent structure—discriminant analysis (OPLS-DA) were performed to discriminate between argan oils from Essaouira, Taroudant, Tiznit, Chtouka-Aït Baha and Sidi Ifni. The correct classification rate was highest for argan oil from the Chtouka-Aït Baha province (90.0%) and the lowest for oils from the Sidi Ifni province (14.3%), with an overall correct classification rate of 51.6%. Pairwise comparison using OPLS-DA could predictably differentiate (≥0.92) between the geographical regions with the levels of stearic (C18:0) and arachidic (C20:0) fatty acids accounting for most of the variance. This study shows the feasibility of implementing authenticity criteria for argan oils by including limit values for trans-fatty acids and the ability to discern provenance using fatty acid profiling.

In Slovenia two superb vegetable oils with high added nutritional value are produced: "Ekstra devisko oljcno olje Slovenske Istre (extra virgin olive oil from Slovene Istra)" and "Stajersko prekmursko bucno olje (pumpkin seed oil from Slovenia)". Their quality and genuineness must be monitored as adulteration can easily be undertaken. Olive oil genuineness determination experiences can show how analyses following an experience data-driven decision tree gathering several chemical determinations (fatty acids, (E)-isomers of fatty acids, sterol and tocopherol determinations) may be helpful in assessing the pumpkin seed oil from Slovenia genuineness. In the present work a set of HPLC triacylglycerol determinations was performed, based on the nine main triacylglycerols (LLLn, LLL, PLL, LOO, PLO, OOO, POO, SPL, and SLS) on a limited number of different pumpkin seed oils from northeastern Slovenia. The performed determinations showed that stereospecific analyses of triacylglycerols together with other chemical determinations can be useful in building a protocol for the evaluation of the genuineness of pumpkin seed oil from Slovenia.

The olive variety 'Istrska belica' is well known for its numerous positive properties, such as resistance to low temperature and high oil content. The aim was to determine the variations in the levels of phenolic compounds and sensory properties during storage of 'Istrska belica' virgin olive oil. The profile of the phenolic compounds and sensory properties of 'Istrska belica' olive oil were further compared with those for other varieties, including 'Leccino' and 'Maurino'. The content of phenolic compounds of the olive oils decreased after 1 year and 2 years of storage. After 2 years of storage, the levels of oleuropein and the ligstroside derivates significantly decreased, while the end-stage compounds tyrosol and hydroxytyrosol increased. These data show that after 1 year of storage, the 'Istrska belica' olive oil preserves similar intensities for bitterness and pungency, and similar oleuropein and ligstroside derivates levels. In contrast to the other oils analysed, the intensities of bitterness and pungency of 'Istrska belica' olive oil decreased greatly only after 2 years of storage. Moreover, the phenolic compounds content, and oleuropein and ligstroside derivates levels, and the intensities of bitterness and pungency were the highest in fresh 'Istrska belica' olive oil, compared to the other olive oils analysed. Overall, 'Istrska belica' olive oil has important advantages over olive oil from other varieties that are grown in the Istria region.

Olives affected by active and damaging infestation (olive fruit fly Bactrocera oleae (Rossi)) were assayed for their chemical composition. Biophenols were determined by HPLC, sterols, triterpenic dialcohols, and fatty acids by gas chromatography analysis. The acquired data were statistically analyzed. Oils produced from “Istrska belica” fruit affected by active infestation compared to the oils made from fruit affected by damaging infestation showed higher amounts of total oleuropein biofenols (377.3 versus (vs.) 106.6 mg/kg), total biophenols (755 vs. 377 mg/kg), lignans (85.3 vs. 32.9 mg/kg), the dialdehydic form of decarboxymethyl oleuropein aglycone (DMO-Agl-dA) (148.3 vs. 49.0 mg/kg), its oxidized form (DMO-Agl-dA)ox (35.2 vs. 8.5 mg/kg), the dialdehydic form of oleuropein aglycone (O-Agl-dA) (61.1 vs. 8.0 mg/kg), the dialdehydic form of ligstroside aglycone (L-Agl-dA) (63.5 vs. 28.0 mg/kg), the aldehydic form of oleuropein aglycone (O-Agl-A) (40.6 vs. 8.4 mg/kg), and lower amounts of tyrosol (Tyr) (6.0 vs. 13. 9 mg/kg) and the aldehydic form of ligstroside aglycone (L-Agl-A) (13.8 vs. 40.3 mg/kg). Higher values of stigmasterol (2.99%) and lower values of campesterol (2.25%) were determined in oils affected by damaging infestation; an increase in triterpenic dialcohols was also observed (3.04% for damaging and 1.62% for active infestation). Oils affected by damaging infestation, compared to active infestation, showed lower amounts of oleic acid (73.89 vs. 75.15%) and higher amounts of myristic (0.013 vs. 0.011%), linoleic (7.27 vs. 6.48%), and linolenic (0.74 vs. 0.61%) acids.