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The nutritional quality and sensory properties of virgin olive oils (VOO) are strongly influenced by a complex endogenous enzyme system. The activity of these enzymes can be influenced by the process conditions during oil production. The aim of the present study was to determine the influence of flash thermal treatment (FTT) on lipoxygenase activity and on the formation of volatile compounds. Olive fruits from Istarska bjelica and Levantinka were used for this experiment. FTT was performed as a pretreatment to malaxation by rapid cooling or heating from 15 to 40 °C. Lipoxygenase was isolated from the olive paste after malaxation, and its activity was determined by measuring the concentration of hydroperoxides formed by the HPLC method. The volatile compounds of VOOs were analyzed by SPME - GC/MS. The results show that lipoxygenase activity is cultivar dependent, with Levantinka having significantly higher activity. Consequently, Levantinka VOOs have significantly higher concentrations of lipoxygenase pathway volatile compounds. FTT had no significant effect on lipoxygenase activity, although the trend of decreasing activity with increasing temperature was observed. However, volatile compounds of the produced oils were temperature dependent, and their concentration increases from 15 °C to 20 °C for Levantinka and to 25 °C for Istarska bjelica. Thereafter, it gradually decreases with increasing temperature. The concentration of secondary oxidation products was also determined to determine the influence of the temperature on the oxidation processes. Neither the cultivar nor the FTT had any effect on the oxidation products.

The aim of the present study was to investigate the effect of fertilization practices, especially with nitrogen (N), on N leaf status, fruit and oil yield, and oil quality parameters in orchards of Central Dalmatia. Questionnaires done by more than 100 olive growers revealed that fertilization practices vary widely. Based on the data obtained, 22 orchards with most prevailing practices in N application were selected for detailed soil, leaf and fruit analyses. The samples were taken from trees of the Oblica cultivar. N concentration in leaves averaged 1, 69% and ranged from 1.09 do 2.36% and correlated mainly with the intensity of agrotechnical prctices and fertilizer use expressed in the questionnaires. Based on results from 22 orchards, an additional subselection of 9 orchards with low, optimal nad high N leaf concentration was made. Hand-picked olives had on average 15, 5% of oil, fruit N concentration ranged from 0.43 to 0.71% ; with an average of 0.57%. The results showed correlation between N level in leaves and fruits, which was more pronounced in leaves with optimal N status. It was also found that N concentration in fruits was higher with lower K concentration in leaves. Significant negative correlation was found between N content in fruits and phenolic content in virgin olive oil, with increased N leading to sharp decrease in phenols in oil. As a basis for future studies on N nutrition in olive, fertilization experiment with three N supply levels was established on the cultivar Oblica.

Endogenous olive enzymes represent a crucial link between fruit composition and the nutritional and sensory characteristics of virgin olive oil. Enzymes such as β-glucosidase, polyphenol oxidase and peroxidase influence the content and composition of polyphenols, the main antioxidants in virgin olive oils. Lipoxygenase and hydroperoxide lyase convert fatty acids into volatile components responsible for the specific sensory properties of the oil. The aim of the present study was to determine the influence of fruit ripeness on the enzymatic activity of β-glucosidase, polyphenol oxidase, peroxidase and lipoxygenase in four Croatian autochthonous olive cultivars. For this experiment, olive fruits from two Dalmatian (Oblica and Levantinka) and two Istrian cultivars (Rosulja and Istarska bjelica) grown in their area of origin were harvested on three different harvest dates, from October 28 to November 9, 2021. The β-glucosidase, polyphenol oxidase and peroxidase were isolated from the acetone powder of the paste. The activity of these enzymes was determined spectrophotometrically, and the formation of p-nitrophenol from p-nitrophenyl glucopyranoside was measured for β-glucosidase, the formation of o-quinone from catechol for polyphenol oxidase, and the formation of tetraguaiacol from guaiacol for peroxidase. Lipoxygenase was isolated directly from olive paste, and its activity was determined by measuring the concentration of formed hydroperoxides by HPLC. The activity of β-glucosidase was detected only in a few samples, which was not sufficient to determine the influence of the factors studied on its activity. Polyphenol oxidase activity increased between the first and second harvest dates, and this increase was significantly higher in the Istrian cultivars. At later harvest dates, the activity decreased, but to a greater extent in the Dalmatian varieties. Peroxidase activity was significantly affected by both ripening and cultivar. Istrian cultivars had significantly higher peroxidase activity than Dalmatian cultivars. The activity was lower in riper fruits, with the exception of Levantinka, which had the highest activity in ripe fruits. Lipoxygenase activity was influenced primarily by harvest date: on the first date, activity was highest in Rosulja and Levantinka, on the second date in Istarska bjelica, and on the third date in Oblica. Throughout the harvest period, lipoxygenase activity was higher in Rosulja and Levantinka than in the other two cultivars.

Innovative technologies are being widely studied for their application in the production of virgin olive oil. Flash thermal treatment is one of these techniques, since the regulation of temperature allows control over complex enzyme systems that affect the nutritional value, oxidative stability and sensory profile of virgin olive oil [1-3]. The aim of this study was to determine the effects of flash thermal treatment (both cooling and heating) on the antioxidant activity of virgin olive oil from four different varieties (Oblica, Rosulja, Istarska bijelica and Levantinka). Flash thermal treatment was applied at 6 different temperatures in the range of 15-40 °C. It was used as a malaxation pretreatment for the production of virgin olive oil on a laboratory scale using the Abencor system. The antioxidant activity of the produced oils was determined using the DPPH method previously described by Kraljić et al [4]. The results show a significant influence of the variety and pretreatment on the antioxidant activity of virgin olive oil, as well as their interaction. Rosulja had the highest antioxidant activity (90.8% on average) compared to the other three varieties (84.3, 75.6 and 74.8% for Oblica, Istarska bijelica and Levantinka, respectively). In relation to the applied flash thermal treatment, Oblica, Rosulja and Levantinka showed significantly higher antioxidant activity at the highest temperature (40 °C), while Istarska bijelica responded better to mild temperatures (20-30 °C).

Olea europaea L. products such as extra virgin olive oils and olive leaves contain a wide variety of bioactive compounds that are profoundly analyzed for their various pharmacological properties. Scientific data on composition analyses of olive by-products such as olive milled waste, fruit pulp and seeds exist, however, information’s regarding the phenolic composition of olive organs as buds and/or flowers are available really scarce. Phenolic compounds in plants are of considerable physiological and morphological importance, playing an important role in pigmentation, growth, and reproduction, but also for resistance to pathogens. Therefore, the aim of this study was to characterize olive buds and open flowers of two Dalmatian cultivars ‘Oblica’ and ‘Lastovka’, and determine whether these two cultivars differ in phenol composition within the analyzed organs. From the buds and open flowers polar fractions were extracted (3 of each cultivar) using solid–liquid extraction with hydro-alcoholic solvent, while the extracts were analyzed using high performance liquid chromatography. Among twenty-three identified compounds classified into groups that have been characteristic for olive products as secoiridoids, phenolic acids, phenolic alcohols, flavonoids, and lignans, oleacin and oleuropin were the most abundant in olive buds of both studied cultivars. Their significantly higher content had ‘Lastovka’ compering to ‘Oblica’. In ‘Oblica’ open flowers oleacin and more over oleuropein content increases relatively to buds, although the highest increase was established for the verbascoside that was most abundant compound in ‘Oblica’s open flowers. For ‘Lastovka’ similar trend of increase was visible with an indication that the highest proportion recorded in ‘Lastovka’ open flowers was oleacin. Except phenolic’s, dynamics of anthocyanins cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside was followed. This data are the first report on the characterisation of phenolic compounds in buds and open flowers of the Croatian olive cultivars.

Korištenje podloga različito utječu na rast i razvoj rajčice te na kvalitetu ploda. Stoga je cilj ovog rada bio utvrditi utjecaj uzgoja na rzličitim podlogama na kvalitetu ploda rajčice. Pokus s kultivarom rajčice Matissimo F1, cijepljenim na sedam komercijalnih podloga za rajčicu Arnold (A) DR0141TX (DR), Maxifort (MX), Multifort (MF), Optifort (OF), Emperador (EM) i Suzuka (S) je postavljen u plasteniku na području Trogira u proljetno-ljetnoj sezoni. Biljke su posađene u tlo na PE crni film na razmak 50 x 140 cm i uzgojene su na dvije grane. Rani prinos bio je veći kod A (3, 95 t 1000 m-2) i EM (3, 84 t 1000 m-2), dok je ukupni najveći prinos bio na podlozi EM (33, 15 t 1000 m- 2). Plodovi uzgojeni na MF imali su veći paramter boje a* i h (24, 5 i 51, 6). Boja mesa ploda a* ovisila je o podlozi i poziciji mjerenja. Rub ploda najcrveniji je kod MF (13, 6) i EM (13, 5), dok je zona sjemena najmanje crvena kod MX (11, 9) i EM (13, 4). Središnji dio ploda najcrveniji je kod podloga OF (24, 4) i A (23, 1). Najviši udio topivih šećera postigli su plodovi uzgojeni na OF i S (3, 95° Brix) dok je najmanji utvrđenna MX (3, 2° Brix). Kod A izmjeren je najvši EC soka ploda (4, 96 dS m-1), dok je najviši pH zabilježen na S (4, 33). Najveći gubitak mase ploda zabilježen je sedmog dana čuvanja kod DR (3 %). Čvršće plodove imale su biljke uzgojene na DR, OF, MX i EM. Iako su podloge različito utjecale na promatrana svojstva, podloga EM se ističe po prinosu, boji mesa i čvrstoći.

U okviru projekta ''Bioraznolikost i molekularno oplemenjivanje bilja'' provedena je molekularna karakterizacija divljih i kultiviranih maslina u Hrvatskoj upotrebom 12 SSR (Simple Sequence Repeates) markera s ciljem dobivanja molekularnih profila specifičnih za genotipove uključene u ovo istraživanje. Sorte maslina smo prikupili iz kolekcijskih i proizvodnih nasada, dok su divlje masline izdvojene iz devet populacija s područja otoka Brijuna, Paga, Dugog otoka, Šolte, Hvara, Visa, Lastova, Mljeta i poluotoka Pelješca. Rezultati su pokazali jedinstvene profile za mnoge sorte i divlje masline te izdvojili tri slučaja sinonimije. Dendrogram izrađen metodom neighbor- joining je razdvojio grupu divljih od kultiviranih genotipova. Sorte su se većinom grupirale u zajedno, ali su pokazale i povezanost s divljim maslinama. Dobiveni rezultati su istaknuto bogatstvo genetskih resursa masline u Hrvatskoj, dajući informacije za njihovo očuvanje.

Olive fruit fly (Bactrocera oleae, Rossi) and olive moth (Prays oleae, Bern.) are the most economically important olive pests, causing yield losses in all olive-growing areas where they are detected. For years, the use of pesticides was the main method of controlling them, and their intensive use had negative effects on the environment. Therefore, the EU aims to reduce the use of pesticides by 50% by 2030 and 100% by 2050. For all these reasons, more effective non-pesticidal baits are needed for monitoring and/or control of B. oleae and P. oleae. Current knowledge indicates that several insect species are attracted to natural volatiles, including pheromones, host plants, yeasts, and bacterial volatiles. Since the interaction between olive trees and olive pests has not been adequately studied, the objective of this study was to identify olive tree volatiles that might be responsible for attracting B. oleae and P. oleae and to test them in olive orchards. During the study, about 70 different volatiles were identified from olive flower buds, 4-6 mm fruits and leaves, and 100 different volatiles were identified from olive fruits at three stages of ripeness (green, semi-ripe and ripe), mainly belonging to the groups of esters, saturated hydrocarbons, aldehydes, alcohols, terpenes and sesquiterpenes.These results are used to identify volatiles that could be responsible for olive moth attraction. Therefore, selected volatiles will be tested in delta traps in several olive orchards. Volatiles that could be responsible for olive fruit fly attraction will also be selected and tested on yellow sticky traps in other olive orchards. The results of our research could provide answers to many questions about the relationship between olives and pests. Finding volatiles that could be responsible for attracting harmful species could lead to the development and improvement of new attractants that could be a useful tool for monitoring and/or controlling B. oleae and P. oleae in the future.

Maslinin moljac (Prays oleae Bern.) jedan je od najvažnijih štetnika masline koji svake godine čini štete. Godinama je jedna od glavih mjera suzbijanja istog bila primjena pesticida, čija je intenzivna uporaba imala negativan utjecaj na okoliš. Stoga je EU uvođenjem Europskog zelenog plana obvezala svoje članice na smanjenje utroška pesticida za 50 % do 2030. godine. te 100 % do 2050. godine. Zbog svega navedenog prijeko je potrebno iznaći nova rješenja koja bi bila učinkovita u suzbijanju moljca i ekološki povoljna za okoliš. Trenutne spoznaje govore da različite vrste kukaca privlače hlapive tvari biljke domaćina. Kako interakcija masline i moljca još uvijek nije istraživana, cilj istraživanja je bio identificirati hlapive tvari masline koje bi mogle biti odgovorne za privlačenje istog, te ih testirati u maslinicima. Na odabranim sortama masline uzorkovan je biljni materijal te su identificirane hlapive tvari pomoću HS-SPME/GC-MS uređaja. Tijekom istraživanja identificirano je oko 70 različitih hlapivih tvari, među kojima su odabrana dva aldehida, dva alkohola i ester, te su testirani pojedinačno i u kombinacijama u maslinicima pomoću delta lovki. Rezultati ovog istraživanja su pokazali kako su alkohol i kombinacija aldehid:alkohol:ester, kao dodatak feromonu, privukle puno veći broj moljaca od lovki koje sadrže samo feromon. Ovo otkriće može dovesti do razvoja novog i poboljšanog mamaca za maslinovog moljca, koji bi se u budućnosti mogao koristiti za monitoring i/ili suzbijanje istog.

The research activities of the project "Biodiversity and Molecular Plant Breeding" were conservation, phenotyping and genotyping of olive genetic resources in Croatia. During the field expeditions, nine populations of wild olives were selected and included in the study together with cultivars from the field collections at Institute for Adriatic Crops and from the production orchards. Qualitative and quantitative traits of leaf, fruit, stone and flower were assessed at 97 wild genotypes, 28 autochthonous and 35 foreign cultivars. Fruit and stone traits showed high discriminatory capacity between wild olives and cultivars. The samples of 223 genotypes were molecularly characterized using 12 SSR (Simple Sequence Repeats) markers. The results showed high genetic variability of the Croatian germplasm separating the wild genotypes from the cultivated ones. Chemical and sensory profiling of 54 monovarietal extra virgin olive oils showed that fatty acids, phenolic content and sensory profile are predominantly characteristics of a cultivar. According to obtained results the plant material was propagated and used for establishment of new collection orchard and in greenhouse experiments to assess the sensitivity of different genotypes to abiotic and biotic stresses. The alternate bearing of Oblica, the main Croatian olive cultivar was studied in production orchard. The trees with different fruit load showed differences in flower and fruit morphology as in fruit and oil yields. The olive research group at Institute for Adriatic Crops will continue to work in selection, evaluation and preservation of olive autochthonous and wild genotypes.

The olive fruit fly (Bactrocera oleae, Rossi) and olive moth (Prays oleae, Bern.) are economically the most important olive pests, causing yield losses in all olive growing areas where detected. For years, the use of pesticides was the main method for their controlling, which intensive use had a negative effect on the environment. Therefore, the EU is seeking to reduce pesticide use by 50 % by 2030 and 100 % by 2050. Due to all the above, more effective non-pesticide lures for B. oleae and P. oleae monitoring and/or controlling are needed. Current knowledge suggests that different insect species are attracted by volatile natural compounds, including a pheromones, host-plant, yeasts and bacterial volatiles. Since the interaction between olive tree and olive pests has been purely investigated, the aim of this study was to identify the olive tree volatiles that could be responsible for B. oleae and P. oleae attracting, and to test them in olive orchards. Plant material was sampled on selected olive cultivars and volatiles were identified using HS- SPMEGC-MS. During investigation, around 70 different volatiles were identified from olive flower buds, fruits 4-6 mm and leaves, and 100 different volatiles from olive fruits in three ripening stages (green, half ripe and ripe), mostly belonging to the groups of esters, saturated hydrocarbons, aldehydes, alcohols, terpenes and sesquiterpenes. These results, as a pull of data will serve for identifying volatiles that could be responsible for olive moth attracting, thus selected volatiles will be tested in delta traps in multiple olive orchards. Volatiles that could be responsible for olive fruit fly attracting will be also selected and tested on yellow sticky traps in other olive orchards. The results of our research could provide answers to many concerns about the olive/pests relationship. Finding volatiles that could be responsible for attracting harmful species may lead to the development and improvement of new attractants, that could be a useful tool for monitoring and/or controlling of B. oleae and P. oleae in the future.

Kao jedna od najvažnijih mediteranskih voćnih vrsta, maslina (Olea europaea L.) je poznata kao bogat izvor fenola i drugih nutritivno važnih spojeva. Proteklih godina na Institutu za poljoprivredu i turizam provedena su brojna istraživanja vezana uz utjecaj ishrane masline na fenolne komponente lista ili maslinovog ulja.Temeljem odabranog seta podataka prikazanih u ovom radu, sorta 'Istarska bjelica' pokazala je najveću koncentraciju oleuropeina u listu i ukupnih fenola u maslinovom ulju. U hidroponskom pokusu smanjena razina magnezija u hranivoj otopini povećala je, a niska razina mangana, cinka i bakra smanjila koncentraciju ukupnih fenola u listu masline sorte 'Istarska bjelica'. Folijarna gnojidba sumporom imala je pozitivan učinak na količinu ulja po stablu u rodnoj godini neovisno o proučavanoj sorti.

The olive tree (Olea europaea L.) is an important fruit tree species in all Mediterranean countries, including Croatia, which is characterized by a fair number of indigenous, locally grown varieties, and by a rich heritage of wild olive trees still found on numerous islands along the Adriatic coast. In the framework of the project "Biodiversity and Molecular Plant Breeding", the samples of 223 olive varieties and wild olives were collected from different locations in the olive growing area and molecularly characterized using 12 SSR (Simple Sequence Repeats) markers. The results showed a unique profile for most cultivars and wild trees, except for three cases of synonymy, probably attributable to misnaming. Overall, the Croatian germplasm showed high genetic variability. The neighbor-joining dendrogram separated a group of wild genotypes originated mostly from the middle and southern Dalmatian islands. Cultivated genotypes mostly clustered together but they also showed relationship with wild germplasm. The results obtained underlined the richness of the genetic resources of the olive tree in Croatia, providing information for the protection of genetic material and monovarietal oils.

Godinama je zaštita masline (Olea europea L.) od štetočinja, kod nas i u svijetu, bila usmjerena samo na uporabu pesticida, što je u zadnjih nekoliko desetljeća rezultiralo negativnim učinkom na okoliš. Očuvanje biološke ravnoteže i cjelokupnog agroekosustava, ključni je problem današnjice. Intenzivne agrotehničke mjere narušavaju sklad biocenoze maslinika, stoga se danas u maslinarstvu sve više pribjegava integriranom ili ekološki prihvatljivom sustavu proizvodnje u kojima je ograničena uporaba pesticida. Dosadašnja istraživanja pokazuju da prirodne hlapive tvari, uključujući feromone, hlapive tvari biljke domaćina, kvasaca i bakterija imaju utjecaj na ponašanje različitih vrsta kukaca. Cilj ovog istraživanja je izolacija i identifikacija hlapivih tvari masline te pronalazak onih koje bi mogle biti odgovorne za privlačenje najvažnijih štetnika masline. U sklopu istraživanja izolirane su i identificirane biljne hlapive tvari cvijeta, ploda i lista Oblice u različitim fazama zrelosti ploda pomoću HS-SPME/GC-MS uređaja. Identificirano je više od 40 hlapivih tvari koji većinski pripadaju skupinama estera, zasićenih ugljikovodika, aldehida, alkohola, terpena i seskviterpena. Rezultati istraživanja mogli bi dati odgovore na mnoge nedoumice o uzajamnom odnosu maslina/štetnik, koji bi rezultirali velikim doprinosom u zaštiti bilja RH, ali i u svijetu.

Šipak (Punica granatum L.) se tradicionalno uzgaja u mediteranskom dijelu Republike Hrvatske, a najviše na području srednje i južne Dalmacije. Na navedenom području izdvojene su najinteresantnije primke te umnožene i posađene u kolekcijski nasad nacionalne banke biljnih gena RH smještenom na Institutu za jadranske kulture Split. Tijekom četverogodišnjeg istraživanja provedena je morfološka karakterizacija 19 primki iz kolekcije od kojih je 9 upisanih u CPGRD bazu, 7 je potencijalnih i 3 su introducirane primke. Morfološka karakterizacija provedena je temeljem UPOV deskriptora za šipak. Opisana su kvantitativna i kvalitativna svojstva stabla, lista, cvijeta i ploda. Analizom rezultata utvrđena je značajna morfološka raznolikost istraživanih primki. Deset primki pripada skupini slatkih sorata, a odlikuju se svjetlijom bojom kore (zeleno-žuto-roza). Slatko - kisele i kisele sorte odlikuju se intenzivno crvenom bojom kore. Introducirane primke imaju tamniju boju kore i arilusa te su slatko kiselog do kiselog okusa pogodne za preradu.

Maslina (Olea europaea L.) je mediterska voćna vrsta koja se u pravilu uzgaja na plitkom i skeletnom tlu s niskim kapacitetom tla za vodu u zoni korjena. Na takvim tlima je navodnjavanje neizostavna agrotehnička mjera u uzgoju i proizvodnji visoko kvalitetnog maslinovog ulja. Cilj ovog rada je utvrditi kako različiti obroci vode i njihov broj kod navodnavanja na heterogenom i skeletnom tlu utječe na kvalitetu i sastav djevičanskog maslinovog ulja dobivenog od plodova introducirane sorte maslina Coratina. Poljski pokus je proveden u sklopu projekta „SAN – Smart Agriculture Network“ (SAN - KK.01.2.1.01.0100) na 24 stabla masline sorte ‘Coratina’ u 2019. godini na lokaciji Žman (Dugi otok). Navodnjavanje je provedeno pomoću sustava kap na kap sa četiri varijante u tri ponavaljanja. Varijante u pokusu predstavljale su primjenjene načine navodnjavanja: K-Kontrola - stabla masline bez navodnjavanja u vegetaciji (0 L vode po stablu), T1 - proizvođačka praksa (obroke je određivao proizvođač prema iskustvu (448 L vode po stablu u pet obroka)), T2 - SAN praksa (obroci su određivani s obzirom na evapotraspiraciju i fenofazu razvoja masline, s do 80 % poljskog kapaciteta tla za vodu, isto kako će ih određivati i SAN tehnologija koja je u razvoju - 560 L vode po stablu u osam obroka) i T3 – dodavanje obroka vode do 100% od izračunate evapotraspiracije (800 L vode po stablu u osam obroka). Određen je poljski kapacitet tla za vodu, a evapotranspiracija je izračunata pomoću meteopostaje tipa Pinova. Plodovi maslina ubrani su s 12 stabala (3 stabla po tretmanu) i prerađeni odvojeno u ulje korištenjem Abencor sustava. Statističkom obradom podataka (jednosmjernom analizom varijance i povratnim testom (Duncan)) istražen je utjecaj navodnjavanja na osnovne parametre kvalitete ulja: antioksidacijska aktivnost, sastav masnih kiselina i udio fenolnih tvari. Mjeranja osnovne analize ulja su pokazala da postoji razlika između peroksidnog broja, slobodnih masni kiselina, i karatenoida koji su bili najveći na kontroli, dok kod krolofila i K brojeva nije utvrđena razlika. Antioksidativna aktivnost maslinovog ulja bila je najveća na kontroli u odnosu na ostale tretmane. Utvrđen je utjecaj istraživenih praksi navodnjavanja na sedam od petnaest ispitivanih masnih kiselina. Postoje razlike kod polifenolnog sastav ulja i to kod hidroksitirosola i tirosola koji su bili najveći na T3, a najmanji na kontroli. Navodnjavanje masline u istraživanim praksama utjecalo je na sastav i kemijske parametre maslinovog ulja kod sorte Coratina na lokaciji Žman.

Onion (Allium cepa L.) is an important horticultural crop with a worldwide production of 93 168 548 tons while in 2016 in Croatia 26 858 tons of dry bulb onion were harvested, with an average yield exceeding 32 t ha-1 (FAOSTAT). Critical decision that onion growers must address is optimization of plant density which determines cost, plant yield and bulb quality. Objective of this study was to evaluate the effects of different within and between row spacings on Istrian purple and yellow onion bulb characteristics. The field experiment was conducted during two vegetative seasons and was set up as a randomized block design with two factors: 20, 30 and 50 cm between row spacing and 10, 15 and 20 cm within row spacing. Bulb weight increased as between row spacing increased for Istrian purple and red onion, while in row plant spacing had significant effect only for yellow onion. Row spacing had similar effect on Istrian purple and yellow onion bulb height and diameter (P < 0.001 for both genotypes). Flavonoid, anthocyanin and sugar content of both genotypes were less affected by different row spacings than observed bulb morphological traits. These results suggest that it is possible to adjust planting density of Istrian purple and yellow onion in order to obtain marketable bulbs without significant changes in bulb quality.

Fruit samples of domestic (‘Barski slatki’, ‘Ciparski’, ‘Glavaš’ and ‘Sladun’) and foreign pomegranate cultivars (‘Granada’, ‘Hicaznar’ and ‘Wonderful’) were collected in productive pomegranate orchard in Metković (Croatia) and compared their pomological and chemical properties. The results on the main pomological and quality traits indicated significant statistical differences among domestic and foreign cultivars. Fruit weight of investigated cultivars varied from 510.5 to 355.1 g and the highest was recorded in ‘Glavaš’, while difference in fruit weight between other cultivars was not found. Color of peel, arils and juice of domestic cultivars was yellow to red, red and light red to red, receptively, while in the foreign cultivars intensively red and dark red. Arils yield of ‘Barski slatki’ and ‘Ciparski’ (57.7 and 60.8%, receptively) was higher compared with other investigated cultivars. Juice yield of domestic cultivars was higher than that of foreign. Total soluble solid (TSS) of ‘Hicaznar’ (18.6%) was higher than that of ‘Barski slatki’ (17.0%), ‘Ciparski’ (14.7%) and ‘Wonderful’ (16.6%). Total acidity (TA) of ‘Glavaš’ (2.24%) and ‘Hicaznar’ (2.08%) was the highest while of ‘Barski slatki (0.58%), ‘Ciparski’ (0.37%) and ‘Sladun’ (0.59%) the lowest. According to the TA and (TSS/TA) ‘Glavaš’ and foreign investigated cultivars belonged to the group of sour-sweet cultivars while ‘Barski slatki’, ‘Ciparski’ and ‘Sladun’ belonged to the sweet cultivars. Foreign cultivars had higher total phenolic content (TPC) that ranged from 679.6 to 906.6 mg 100 g-1 d.w., than domestic ones. ‘Hicaznar’ stood out as a cultivar with the highest TPC and anthocyanin content (86.3 mg 100 g-1 d.w.). Non-flavonoid content in studied cultivars ranged from 160.6 to 385.5 mg 100 g-1 d.w. and antioxidant activity measured by 1, 1-diphenyl-2-picrylhydrazyl from 60.2 to 74.5%. Results of this survey are a basis for use defining of the pomegranate fruit.

Virgin olive oil (VOO) has significant health impact because of its peculiar chemical composition. Among phenolic compounds in VOO, the secoiridoid derivates oleocanthal and oleacein are responsible for antioxidant, antimicrobial, anticancer and hypoglycemic activity. Furthermore, oleocanthal showed stronger anti-inflammatory effect compared to ibuprofen. In this study, we investigated the accumulation of oleocanthal, oleacein and other phenolic compounds (hydroxytyrosol, tyrosol, oleuropein aglycon, apigenin, luteolin and ligstroside aglicon) in monovarietal VOOs obtained from Croatian autochthonous cultivar Oblica. Olive fruits were harvested in 2016 at the same ripening stage from olive groves spread over all Croatian olive cultivated regions. Subsequently olive fruits were processed in oil under the same conditions using laboratory system Abencor mc2. Phenolic extracts were prepared using liquid-liquid extraction with methanol:water mixture (60:40 v/v). Phenolic extracts were analyzed by a 1200 Series liquid chromatograph coupled to a triple quadrupole detector, equipped with ESI source. The results show different concentrations of hydroxytirosol, oleocanthal, oleuropein aglycon and lygstroside aglycon regarding olive cultivation region. Indeed, hydroxytirosol had the lowest concentrations in north Dalmatia while oleocanthal had the highest concentrations in middle Dalmatia, with no differences noticed among other olive regions. The oleocanthal concentrations varied from 112 up to 1082 mg kg-1, while oleacein concentrations from 80 up to 942 mg kg-1. Overall, the results indicated significant variability of phenolic compounds in VOOs from different Croatian regions, thus indicating possible superior therapeutic features from specific VOOs.

Luk (Allium cepa L.) je važna povrćarska kultura te se uzgaja na cijelom području Hrvatske. Istarski ljubičasti i žuti luk nalaze se na listi čuvanih sorti Republike Hrvatske te se tradicionalno uzgajaju na obalnom području Istre. Varijabilnost svojstava lukovice kod ovih sorti je velika, jer ih već generacijama održavaju proizvođači bez kontrole oprašivanja. Tradicionalno se sade iz presadnica tijekom jeseni, te se lukovice beru od lipnja za potrošnju tijekom ljeta. Cilj ovog rada je bio procijeniti varijabilnost svojstava glavica Istarskog ljubičastog i žutog luka. Rezultati su pokazali da postoji velika varijabilnost u boji mesa i pokožice, te je koeficijent varijacije (CV) za boju mesa i pokožice iznosio 11% i 7% kod crvenog, te oko 4 i 7% kod žutog luka. Također, visoki CV (od 7 – 20%) su uočeni za broj ljuski, debljinu pokožice, čvrstoću glavice te sadržaj šećera. Nešto manji CV je uočen za pH lukovice (3 i 5% kod žutog i crvenog luka), te za ukupan sadržaj kiselina (CV ~ 8% za obje sorte). Vrlo veliki CV je uočen kod visine glavice, promjera glavice i mase glavice (CV 17 – 21%, 24 – 30% i 54 – 67%). Koeficijenti varijacije za sadržaj flavonoida su bili veliki, nešto viši za crveni luk (CV 39 – 49%) nego za žuti (CV 32 – 38%). Kod crvenog luka uočena je vrlo velika varijabilnost za sadržaj antocijana. Rezultati ovog istraživanja ukazuju na veliku varijabilnost praćenih svojstava kod obje sorte te na mogućnosti usmjeravanja procesa selekcije prema poželjnim agronomskim i gospodarskim svojstivma.

Analysis of elements in Extra Virgin Olive Oil (EVOO) samples is challenging due to the complex matrix as well as their very low concentrations in oil. Optimization of a previously proposed analytical method consisting of ultrasonic acid extraction and subsequent ICP-MS detection is now allowing determination of 27 elements in EVOO a low pg g-1 level for trace elements. Furthermore, EVOO samples are likely to contain residual pomace, which potentially can influence the elements concentration and distribution. Indeed, our study revealed that pomace residues, when present in EVOO even at small quantity (1 g kg-1), significantly alter concentrations and relative proportions of many elements present in EVOO. Comparative analyses of EVOO samples with and without centrifugation prior to ultrasonic acid extraction confirmed significant influence of pomace residues on elements concentrations. Therefore, an adequate sample pre-treatment (removal of pomace residue) through centrifugation is essential for determining real multi-elemental composition of olive oil. This is critical in application of EVOO multi-element composition in traceability studies and determination of geographic origin of oil.

Extra virgin olive oil is obtained by mechanical processing of olive fruits at temperature up to 27 ºC in each processing step, as a guarantee of the highest oil quality. With prolonged malaxation time the oil yield can increase, but the quality of obtained oil is usually lower. In this paper the influence of different processing conditions (temperature and malaxation time) in monovarietal olive oils from 'Oblica' has been studied, in order to determine better overall quality, antioxidant characteristics and longer shelf life. Different malaxation temperatures (26, 36, 46 ºC) were applied during olive processing on laboratory scale using Abencor mc2 system. For each temperature, the influence of several malaxation times were also examined (30, 45, 60 min). The analyses of free fatty acid, peroxide value, UV spectrophotometric indices was perforemd according to official EEC methods (2568/91). Total phenols content (TPC) was determined using the Folin–Ciocalteau method (Gutfinger, 1981). The sensory evaluation of olive oils was performed according IOC (2007) method. Oxidative stability was measured using Rancimat apparatus while antioxidant activity was detected using DPPH antioxidant assay following the method described by Kalantzakis et al. (2006). Both oxidative stability and antioxidant activity was carried out in fresh oils and during 12 months of oil storage in dark place at the room temperature. Prolonged malaxation had the strongest influence on K-numbers, especially at the temperature of 46 ºC so oils obtained under this conditions were in the category of lampante non-edible oils. Strangely and unexpected, these same oils had very high TPC. The best overall quality was detected in oils obtained 26oC and during shortest malaxation time (30 min.). Same oils had the highest TPC and the best oxidative stability. Sensory analyses of investigated oils showed the highest score for oils processed at 26 ºC and 36 ºC and 30 min of malaxation. The fastest degradation of overall quality was noticed in oils produced at 46 oC i 45 min of malaxation.

Cilj je bio utvrditi komponente vegetativnog i generativnog rasta, prinosa i kvalitete ploda rajčice cijepljene na vlastiti korijen (pozitivna kontrola) kao i na Solanum podloge u uvjetima reduciranog navodnjavanja. Biljke uzgajane s deficitarnim navodnjavanjem i djelomičnim zasušivanjem korijena imale 30% veću efikasnost korištenja vode. Također, biljke uzgajane na podlogama su očekivano pokazale veću efikasnost korištenja vode u odnosu na prinos svježih plodova rajčice. Istraživanja su pokazala da uzgoj na 2 izboja/grane rajčice cijepljene na Solanum podloge uz deficitarno navodnjavanje naglašeno smanjuje troškove bez velikog utjecaja na prihod.

The volatile compounds from virgin olive oil (VOO) are chemical species responsible for its specific flavour. This group of compounds consists mainly of C5 and C6 volatiles that are biogenerated from polyunsaturated fatty acids via lipoxygenase pathway. In this paper the composition of volatile compounds, total phenolic content and sensory profile of monovarietal VOOs from four Dalmatian most common cultivars: Oblica, Lastovka, Levantinka and Krvavica were studied. Fruits from each variety were handpicked at the same ripening stage and processed separately in oil under the same conditions using laboratory oil mill Abencor mc2. All analyzed VOOs were within limits established for extra virgin olive oil category based on chemical parameters. Total phenolic content (TP) of obtained oils were determined spectrophotometrically using modified Gutfinger method and expressed as caffeic acid. The highest TP value was detected in Oblica and Levantinka oils (482.32 mg/kg and 398.85 mg/kg, respectively). Volatile composition of analyzed monovarietal olive oils was determined using headspace solid-phase microextraction with gas chromatography/mass spectrometry (HS-SPME/GC-MS). The most prevalent volatile compound was C6 aldehyde E- 2-hexenal, that contributes to green, fruity, bitter and astringent sensory characteristic of olive oil. The highest value for E-2-hexenal was detected in Levantinka oils (75.89% of total peak area), followed by Lastovka (55.27%) and Oblica (54.86%). In the same time, Lastovka oils had the highest ammount of hexanal (25.72%), C6 aldehide associated with sensory characteristics of green fruitiness, apple and grass. Quantitative descriptive sensory analysis of studied olive oil samples were carried out by a sensory panel using IOC methodology. The sensory profile of Lastovka oil was characterized by medium intensity of olive fruity, green leaves, apple and almonds, strong bitterness and medium pungency. Krvavica oil sensory profile showed the mildest intensity of bitter and pungent of among all analysed oils. Mild to medium fruitiness with grass and ripe apple notes are olfactory characteristics of Krvavica oils.