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The potential effect of pre-inoculation of processing tomato (Solanum lycopersicum L.) plants with arbuscular mycorrhizal fungi (AMF) on yield and fruit properties was investigated in conventional production. Tomato seeds were sown in seedling trays filled with a substrate non-inoculated (AMF-) or inoculated (AMF+) by selected mycorrhizal strains. Seedlings were transplanted in Terra rossa soil and grown in conditions with mineral fertilization and irrigation. Tomato fruits were sampled at harvest. Tomato plants under both treatments had high levels of mycorrhizal colonization, due to applied inoculum (AMF+) or indigenous (AMF-) inoculum present in the soil. Applied AMF+ treatment increased P and decreased K content in tomato fruits. Content of trace elements such as As and V significantly increased, while Pb content significantly decreased in the fruits of AMF+ when compared to the AMF- treatment. No significant effect of AMF+ treatment was observed on yield, fruit quality (soluble solids, pH, total acidity, fruit firmness), lycopene and antioxidant activity of tomato fruits. The overall results suggest that processing tomato is highly susceptible to the indigenous AMF, while seedlings inoculation with selected AMF improves only total phenolic and P fruit content. This means that AMF have a potential application in commercial processing tomato production, however a targeted adaptation of management decissions is required for more extensive results.

Olive oil is considered one of the most valuable vegetable oils and is highly appreciated by consumers for its specific and distinguishable taste and aroma, as well as its nutritional value. Sterols and triterpene diols are important carriers of bioactive properties of olive oil and are responsible for some of the beneficial effects of its consumption on human health, such as lowering serum LDL-cholesterol levels and significantly reducing the risk of cardiovascular diseases. The concentration of total sterols and the proportions of particular sterols and triterpene diols are among the parameters used to verify and prove the authenticity of olive oil in accordance with the EU and other countries’ regulations. Finally, their composition has been shown to have high discrimination potential for ensuring traceability with respect to variety, geographical origin, harvest date, and other factors. For these reasons, the research on sterols and triterpene diols in olive oil is an ever-growing field of scientific interest with great practical importance. This review focuses on all the important aspects of sterols and triterpene diols in olive oil, from their chemical structure, biosynthesis, occurrence and role in plants, health benefits, and their use in official controls of olive oil purity and authenticity, to a conclusive survey on the recent findings about the effects of different factors of influence on their content and composition, with a detailed comparative analysis of studies that investigated the effects of the two most important factors, variety and ripening degree.

The effects of different fertilisation treatments with arbuscular mycorrhizal fungi (AMF) inoculation on AMF root colonisation, fruit yield, nutrient and total phenol contents, volatile compound composition, and sensory attributes of tomato (Solanum lycopersicum L.) were investigated. Mineral, organic, and mineral + organic fertiliser application positively affected tomato yield (35%–50%) and phosphorus concentration (24%–29%) compared with controls. AMF application had a significant impact on the total nitrogen (+9%), manganese (+12%), and hydrophilic phenol (+8%) contents in the fruit. Volatile compounds were affected by the interactive effects of fertilisation and AMF application. The response of tomato fruit sensory quality indicators was relatively modest, with only a few sensory characteristics affected to a lesser extent. Although tomato showed susceptibility to field-native AMF, particular combinations of fertilisation and AMF inoculation were more effective at improving the quality parameters of tomatoes under field conditions applied in this study.

The interactive effects of cultivar, collecting period, and geographical location on the content and composition of biophenols and macro and micronutrients in olive (Olea europaea L.) leaf were investigated. Leaves of six cultivars were collected at three periods in two locations in Croatia. The leaves of Istarska bjelica cultivar had the greatest biophenol (oleuropein) potential, especially those sampled in January and in March at the location of Pag. All the cultivars yielded leaves with the highest concentration of biophenols in March, which coincided with the pruning period. Except for high oleuropein concentration in Istarska bjelica, flavonoids were found to be most useful for differentiating olive leaves according to cultivar. Verbascoside turned out to be the most potent differentiator of collecting periods, while phosphorus and zinc turned out to be most useful for differentiating locations. Despite different agroecological conditions at the two locations, cultivar exhibited a significant effect on olive leaf nutrient composition, which was certainly causally related to that of the biophenols. The results obtained showed that it is possible to plan more well-timed and efficient exploitation of biophenols from olive leaf based on the knowledge about the interactive effects of the three studied factors.

The interactive effects of ripening degree, malaxation duration and temperature on Oblica cv. (Olea europaea L.) virgin olive oil phenols, volatiles, and sensory quality were investigated. Olives were picked at three ripening degrees with International Olive Council indices of 0.68, 2.48 and 4.10, and processed by malaxation at 22 and 30 °C, and at both temperatures for 30 and 60 min. Ripening exhibited the strongest effect, and malaxation duration the weakest. Phenols were generally found to decrease during ripening; however 3,4-DHPEA-EDA and p-HPEA-EDA increased. Similar behaviour was observed for (E)-2-hexenal. Higher malaxation temperature induced an increase in particular important phenols and C6 alcohols, while C6 aldehydes mostly decreased. Interactions between the factors were established, mostly between ripening degree and malaxation temperature: the effect of the latter was most pronounced for ripe olives, especially for 3,4-DHPEA-EDA, p-HPEA-EDA and C6 volatiles. Sensory attributes were generally in agreement with the chemical composition.

Despite having an interesting native olive gene pool and a rapidly emerging olive oil industry, monovarietal extra virgin olive oils (EVOO) from Croatia are relatively unexplored. To investigate the inter-varietal diversity of typical volatile and phenolic profiles of Croatian EVOO, 93 samples from six olive (Olea europaea L.) varieties were subjected to gas chromatography-ion trap mass spectrometry (GC-IT-MS) and ultra-performance liquid chromatography with diode array detection (UPLC-DAD), respectively. Quantitative descriptive sensory analysis was also performed. Analysis of variance extracted many relevant exclusive or partial discriminators between monovarietal EVOOs among the identified volatile compounds and phenols. Successful differentiation model with a 100% correct classification was built by linear discriminant analysis, while the most typical volatiles for each monovarietal EVOO were confirmed by partial least squares discriminant analysis. Diverse typical sensory attributes among the EVOOs were tentatively ascribed to the variations in the composition of volatiles and phenols. It was proven that the approach that comprises GC-IT-MS and UPLC-DAD analysis may provide additional objective information about varietal origin and typicity which successfully complement those obtained by sensory analysis. The approach was characterized as universal in nature, with a significant potential to contribute in strengthening the varietal identities and position on the market of monovarietal and Protected Denomination of Origin (PDO) EVOO.

U ovom je radu ispitan utjecaj filtracije svježih sortnih djevičanskih maslinovih ulja Buže i Istarske bjelice u industrijskom mjerilu na sastav hlapljivih tvari, ukupnih fenola te senzorska svojstva, a uzorci ulja izbistreni filtracijom uspoređeni su s onima koji su izbistreni prirodnom sedimentacijom/dekantacijom nakon šest mjeseci skladištenja. Filtracija je različito utjecala na sastav hlapljivih tvari uzoraka ulja dobivenih od različitih sorata. U ulju sorte Buža je nakon filtracije lagano porastao samo udjel (Z)-2-pentenola, dok se u ulju Istarske bjelice promijenio udjel osam spojeva nakon filtracije (udjeli heksanala, (E)-2-pentenala, (Z)-3-heksenala, (Z)-2-pentenola i (Z)-3-heksen-1-ola su porasli, dok su se udjeli heksil acetata, (E)-2-penten-1-ola i (E)-2-heksen-1-ola smanjili). U svježe filtriranom ulju sorte Buža opaženo je blago smanjenje udjela ukupnih fenola, dok je u ulju sorte Istarska bjelica to smanjenje bilo izraženo, što je uzrokovalo smanjenje intenziteta pikantnosti i gorčine ulja. Sedimentacija/dekantiranje imali su prednost naspram filtracije kod obje sorte, jer su očuvali senzorski profil i udjel ukupnih fenola. Profili arome procijenjeni na osnovi vrijednosti aktivnosti mirisa hlapljivih spojeva i njihovog grupiranja u serije uspoređeni su sa stvarnim senzorskim profilima maslinovih ulja. Dobiveni rezultati mogu imati veliku primjenu u industriji maslinovih ulja tijekom optimiranja tehnologije proizvodnje sortnih djevičanskih maslinovih ulja s očuvanim specifičnim i tipičnim senzorskim svojstvima, ali mogu poslužiti i stručnjacima za izbor metode bistrenja djevičanskih maslinovih ulja prije analize hlapljivih tvari., This study investigates the effect of industrial scale filtration of fresh monovarietal virgin olive oil from Buža and Istarska bjelica cultivars on their volatiles, total phenols and sensory characteristics, and compares the oil samples clarified by filtration with those clarified by natural sedimentation/decantation after six months of storage. Filtration had a different effect on volatiles from the oil samples obtained from different cultivars. In the oil from Buža cultivar immediately after filtration only the amount of (Z)-2-pentenol slightly increased, but in Istarska bjelica the oil filtration affected eight compounds (the amount of hexanal, (E)-2-pentenal, (Z)-3-hexenal, (Z)-2-pentenol and (Z)-3-hexen-1-ol increased, while of hexyl acetate, (E)-2-penten-1-ol and (E)-2-hexen-1-ol decreased). In fresh filtered oil from Buža cultivar a slight decrease of total phenols was observed, while in those from Istarska bjelica the decrease was sharp, causing a decrease in the pungency and bitterness. Sedimentation/decantation had advantages over oil filtration of both cultivars, due to improved effect on the preservation of the sensory profile and the level of total phenols. Tentative aroma profiles based on odorant series obtained from the odour activity values were compared to the actual olive oil sensory profiles. These results could have a high level of applications in the olive oil industry for the optimization of the technology for obtaining monovarietal virgin olive oil with preserved specific and typical sensory characteristics, but also may serve experts to choose an appropriate virgin olive oil clarification method prior to analysis of volatile compounds.

Sterols and triterpene diols in olive oil as indicators of variety and degree of ripening derived from three olive varieties and produced at three different harvesting periods were studied. In order to test the stability of the proposed indicators, oils obtained were stored for 12 months at three different temperatures. Thirty-six samples in total were subjected to GC analysis and results were processed by multivariate chemometric methods (MANOVA, PCA, and SLDA). Campesterol, β-sitosterol, Δ(7)-campesterol/Δ(5,24)-stigmastadienol, clerosterol, uvaol, and campestanol/Δ(7)-avenasterol were established as the indicators of variety of fresh oils, while when stored oils were included in the model, the final three compounds were substituted by 24-methylene-cholesterol/stigmasterol. The most important variables for differentiating fresh oils according to degree of ripening were Δ(7)-campesterol/β-sitosterol, uvaol/stigmasterol, clerosterol/Δ(5)-avenasterol and sitostanol/uvaol, while stored oils were differentiated by campestanol/stigmasterol, erythrodiol, stigmasterol/Δ(7)-campesterol, Δ(5)-avenasterol, 24-methylene-cholesterol/β-sitosterol and 24-methylene-cholesterol. Results demonstrated that sterols and triterpene diols can be used as indicators of variety and degree of ripening among virgin olive oils.