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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.

Plant proteins are receiving a lot of attention due to their abundance in nature, customizable properties, biodegradability, biocompatibility, and bioactivity. As a result of global sustainability concerns, the availability of novel plant protein sources is rapidly growing, while the extensively studied ones are derived from byproducts of major agro-industrial crops. Owing to their beneficial properties, a significant effort is being made to investigate plant proteins’ application in biomedicine, such as making fibrous materials for wound healing, controlled drug release, and tissue regeneration. Electrospinning technology is a versatile platform for creating nanofibrous materials fabricated from biopolymers that can be modified and functionalized for various purposes. This review focuses on recent advancements and promising directions for further research of an electrospun plant protein-based system. The article highlights examples of zein, soy, and wheat proteins to illustrate their electrospinning feasibility and biomedical potential. Similar assessments with proteins from less-represented plant sources, such as canola, pea, taro, and amaranth, are also described.

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).

The oxidative stability of fats and oils is a crucial parameter that determines the shelf life of a product, but also the general use of the fats and oils. Differential scanning calorimetry (DSC) is a promising new technique that is fast, reliable and uses the exothermic character of the oxidation reaction to determine the induction time (in the isothermal DSC method) or the induction temperature (in the non-isothermal, i.e., dynamic DSC method). The objective of the present study was to optimize the conditions of the DSC method to determine the oxidative stability of virgin olive oil. Both the isothermal and dynamic methods were developed on a 214 Polyma DSC (NETZSCH-Gerätebau GmbH) and optimized using extra virgin olive oil from the Croatian market. The parameters studied were sample size (4, 8 and 12 mg), sample preparation (use of an open or a sealed pan with a pinhole), temperature (130, 140 and 150 °C) for the isothermal method and heating rate (5, 10, 15 and 20 °C/min) for the dynamic method. The results show that the DSC method is a reliable method for determining oxidation stability for both isothermal and non-isothermal methods. Sample size did not affect induction time, but a smaller portion size resulted in better reproducibility of the results. Regarding sample preparation, there was no statistical difference between results obtained with an open or sealed aluminum pan. However, it is better to use a hermetically sealed pan with a pinhole to protect the instrument from possible contamination. The induction time at 130 °C was 287 minutes, which was considered unacceptable, while a temperature of 140 °C proved to be optimal. A temperature of 150 °C also showed satisfactory reproducibility of results, but a longer induction time at 140 °C makes it easier to track changes between different oils or during storage. For the determination of the induction temperature (dynamic DSC), a heating rate of 15 °C/min proved to be optimal. Although repeatable results were also obtained with a heating rate of 10 °C/min, the use of a higher temperature rate can significantly speed up the analysis. The other two heating rates were considered unsuitable due to the lack of reproducibility.

Aim: Pulsed electric field (PEF) is an emerging new technology that is finding more and more applications in the food sector. Virgin olive oil is no exception, as its application can significantly increase oil yield. However, changes in the chemical composition of virgin olive oil vary from study to study. This could be due to the fact that the chemical composition of the oil is directly influenced by the endogenous enzymes of the olive fruit responsible for the distribution of polyphenols in virgin olive oil and its sensory properties. Therefore, the aim of this study was to determine the effect of PEF on endogenous olive enzymes in model systems. Methods: Model systems of commercial enzymes (β-glucosidase and lipoxygenase) and their substrates (p- nitropheniygluco-pyranoside and linoleic fatty acid, respectively) were treated with HVG60/1 PEF (Impel, Zagreb, Croatia) for 1, 2, and 5 min with voltages of 0.1 and 0.5 kV/cm2 and a frequency of 25 and 125 Hz. Then, the treated enzyme/substrate solution was incubated at 25°C for 30 minutes to simulate a malaxation process. The activities of the enzymes were determined spectrophotometrically. Results: The activity of PEF-treated enzymes increased 4.5- fold for β-glucosidase and 2-fold for lipoxygenase compared to the untreated enzymes. The β- glucosidase activity measured immediately after PEF treatment was significantly affected by all factors and also by the interaction of voltage and time and frequency and time. Higher voltage resulted in an increase in β-glucosidase activity with longer treatment duration. After an additional 30-min incubation at 25 °C, β- glucosidase activity was affected only by PEF voltage, whereas it increased with higher voltage. Immediately after PEF treatment, lipoxygenase activity for linoleic fatty acid was significantly affected by treatment duration, with longer PEF treatments increasing activity. However, after incubation, longer treatment time resulted in lower amounts of hydroperoxides produced, which might be related to their spontaneous degradation. Conclusion: The introduction of PEF in virgin olive production as a pretreatment of malaxation could lead to a higher concentration of phenols and an improvement of the sensory characteristics of the oil due to an increased enzymatic activity.

The final stage of edible soybean oil manufacture is refining, the most delicate phase of which is bleaching. At this step, undesirable substances are removed, such as pigments, traces of metals, phospholipids and certain degradation products. However, certain valuable compounds such as tocopherols and sterols may also be removed, significant loss of oxidative stability can occur, and fatty acid content may increase. To avoid these negative oil changes, bleaching parameters such as the concentration of bleaching clay, temperature and duration should be optimized. Since bleaching conditions depend on the properties of the bleaching clay as well as on the type of crude oil, bleaching parameters should be optimized with different types of clay for each vegetable oil. Since such optimization has not yet been reported for soybean oil treated with Pure-Flo® Supreme Pro-Active bleaching adsorbent, this study investigates the effect of bleaching parameters on bleaching efficiency, oxidative stability and the content and composition of bioactive compounds (tocopherols and sterols) using the above mentioned clay in this type of oil. Results show that the amount of clay had the greatest influence on bleaching efficiency, especially according to the Lovibond scale, on transparency, and on phosphorus content. Temperature and clay amount significantly affected oxidative stability, in particular the formation of secondary oxidation products. Increasing the amount of clay decreased tocopherol content of the bleached oil. Neutralized soybean oil bleached for 20 min at 95 °C with 1 % Pure-Flo® Supreme Pro-Active bleaching clay showed the highest oxidative stability, best bleaching efficiency, and most favourable sterol content, although tocopherol content was reduced.

In this work an HPLC method for determination of polycyclic aromatic hydrocarbons (PAH) in edible oils on a DACC (donor-acceptor complex chromatography) column coupled with an on-line HPLC system with fluorescent detection. Method was used to determine the content of individual PAHs in the refined sunflower oil, virgin olive oil, cold pressed pumpkin seed oil, dark sesame oil and pumpkin seed oil produced with roasting obtained from domestic market. Calibration and validation were conducted for 13 individual PAHs among which are all 8 PAHs that are listed as priorities for determination in food and environment by both European Commission and US Environmental Protection Agency (EPA). Correlation coefficients of calibration curves for all standards were above 0.999 in selected range and all validation parameters (limit of detection, limit of quantification, accuracy and precision) were within limits set by European regulation. Content of PAHs in cold pressed pumpkin seed oil, roasted pumpkin seed oil and especially dark sesame oil was several-fold higher than the recommendations set by different European oil research and production organizations even though for both pumpkin seed oils it was lower than limits set by official European legislation. High content of cancerogenous heavy fraction PAHs were found in dark sesame oil that advises to limitation of its consumption in human diet.

Fenoli i hlapljive tvari utječu na nutritivnu vrijednost i specifična senzorska svojstva djevičanskog maslinovog ulja. Njihovo nastajanje posljedica je djelovanja endogenih enzima. Iz tijesta maslina sorti levantinka, oblica, rosulja i istarska bijelica u tri roka berbe provedena je ekstrakcija enzima lipoksigenaze. Aktivnost lipoksigenaze određena je dvijema metodama, spektrofotometrijski na 234 nm te pomoću HPLC metode. Ispitivanim metodama utvrđeno je da postoji korelacija rezultata, ali su u HPLC metodi rezultati precizniji. Phenols and volatile substances affect the nutritional value and specific sensory properties of virgin olive oil. They are formed by the action of endogenous enzymes. Lipoxygenase enzyme was extracted from the pulp of different olive types: levantinka, oblica, rosulja and istarska bjelica, in three harvest periods. Lipoxygenase activity was determined by two methods, UV spectrophotometry at 234 nm and using the HPLC method. It was established that there is a correlation of the results with the tested methods, but the results are more precise in the HPLC method.

Ulja i masti predstavljaju najvažnije sirovine u proizvodnji sapuna. Budući da sastav masnih kiselina uvelike utječe na kvalitetu i na karakteristike dobivenog sapuna, neće sva ulja, odnosno masti, odgovarati kao dobar izbor sirovine. Sapuni spadaju u skupinu površinski aktivnih tvari, te kao takvi pokazuju sposobnost pjenjenja, emulgiranja, dispergiranja, močenja i slično. Sapuni su soli viših masnih kiselina, koji se dobivaju postupkom saponifikacije masti natrijevim ili kalijevim hidroksidom, a kao produkt uz sapun nastaje i glicerol koji se dalje iskorištava u različitim industrijama, ovisno o namjeni. Obzirom na teksturu razlikujemo nekoliko vrsta sapuna: toaletni, tvrdi, sapuni ili kreme za brijanje, meki i tekući sapuni. U proizvodnji sapuna često se koriste biljna ulja kokosa, uljane palme, masline, ricinusa koja su opisana u ovom završnom radu. Fats and oils are the most important raw materials in soap production. Since the composition of fatty acids greatly affects the quality and characteristics of the finished product, not all oils or fats will be suitable as raw materials. Soaps belong to the group of surface-active agents, and as such show, the ability to foam, emulsify, disperse and wet. Soaps are salts of fatty acids and are formed through the process of saponification of fats or oils in an alkaline solution of sodium or potassium hydroxide. This reaction produces glycerol as a by-product, which is further used in various industries, depending on the purpose. Depending on the texture, we distinguish several types of soaps: toilet, hard, soaps or shaving creams, soft and liquid soaps. Plant based oils that are often used in soap production are coconut oil, palm oil, olive oil, castor oil, some of which are presented in this thesis.

Provedene su ekstrakcije enzima β-glukozidaze i lipoksigenaze iz pulpe i tijesta maslina hrvatske sorte Oblica smrznutih na dva različita temperatura reţima (-20 °C i -80 °C). Ispitivanje aktivnosti β-glukozidaze se odreĎivalo spektrofotometrijski na 405 nm, a lipoksigenaze na 234 nm. Spektrofotometrijska analiza nije pokazala aktivnost β-glukozidaze u tijestu i pulpi, dok je najveća aktivnost lipoksigenaze zabiljeţena u uzorcima tijesta smrznutih na -20 °C. Ispitivanje ovisnosti aktivnosti β-glukozidaze iz badema (Prunus Dulcis) o varijacijama koncentracija p-nitrofenil glukopiranozida je rezultiralo u Michaelis Menten krivuljom s Km 18,1204 mmol Lˉ¹ i Vmax 3,6152 μmol mLˉ¹ minˉ¹. Ovisnost aktivnosti sojine lipoksigenaze (Glycine Max) o varijacijama koncentracija linolenske masne kiseline je rezultiralo Michaelis Menten krivuljom s Km 6,2800 mmol Lˉ¹ i Vmax od 5,599 μmol mLˉ¹ minˉ¹, dok s linolnom nije pokazalo Michaelis Menten krivulju. Aktivnost β-glukozidaze je proporcionalna s koncentracijom enzima, dok se kod lipoksigenaze nije uspjela utvrditi ovisnost bez obzira na supstrat. Extraction of β-glucosidase and lipoxygenase from pulp and paste of Croatian olive cultivar Oblica frozen at two different temperature regimes (-20 °C i -80 °C). β-glucosidase activity assay was determined at 405 nm and lipoxygenase activity at 234 nm. Spectrophotometric analysis did not determine β glucosidase activity, while the highest lipoxygenase activity was determined in olive paste frozen at -20°C. A study of dependence of almond β-glucosidase (Prunus Dulcis) activity on variations of p-nitrophenil glucopiranoside concentrations resulted in Michaelis Menten curve with Km 18,1204 mmol Lˉ¹ i Vmax 3,6152 μmol mLˉ¹ minˉ¹ . Dependence of soy bean lipoxygenase (Glycine Max) activity on variations of linolenic acid resulted in Michaelis Menten curve with Km 6,2800 mmol Lˉ¹ i Vmax 0,5504 μmol/mL min, while on variation of linoleic acid concentrations did not result in Michaelis Menten curve. β glucosidase acitivity is proportional to the enzyme concentration, while lipoxygenase acitivity dependence was not determined regardless of the substrate

Proizvodnja djevičanskog maslinovog ulja (DMU) može se odvijati tradicionalnim ili modernim postupkom. Uz standardne metode koje se koriste tijekom proizvodnje ulja, sve se više uočavaju prednosti novih tehnologija: ultrazvuka, pulsirajućeg električnog polja (PEP-a) i mikrovalova. Cilj ovog rada je opisati način na koji nove tehnologije funkcioniraju te predstaviti njihovu primjenu u proizvodnji DMU. Ultrazvuk se može koristiti za ekstrahiranje bioaktivnih polifenola i obradu otpadnih voda maslinovog ulja. Uz proces malaksacije može poboljšati prinose, sastav i kvalitetu DMU. PEP poboljšava ekstraktivnost i kvalitetu DMU te primjenu nalazi i u ekstrakciji fenolnih spojeva iz komine maslina. Mikrovalovalno potpomognuta ekstrakcija koristi se za uklanjanje pigmenata i tokoferola, a korištenje mikrovalova u obradi maslinovog tijesta rezultira niskom oksidacijom DMU, većom koncentracijom hlapljivih spojeva u ulju te visokom kvalitetom proizvoda. The production of virgin olive oil (VOO) can be done using traditional or modern process. In addition to the standard methods used during oil production, the advantages of new technologies: ultrasound, pulsed electric field (PEF) and microwaves are being observed. The aim of this paper is to describe how new technologies work and to present their application in the production of VOO. The ultrasound can be used to extract bioactive polyphenols and in olive oil wastewater treatment. With the malaxation process, it can improve the yields, composition and quality of VOO. PEF improves extractivity and quality of VOO and can also be used in the extraction of phenolic compounds from olive pomace. Microwave assisted extraction is used to remove pigments and tocopherols, and the use of microwaves in olive paste processing results in low oxidation of VOO, a higher concentration of volatile compounds in oil and high product quality.

Cilj ovog preglednog rada je istražiti utjecaj endogenih enzima ploda masline na kemijski sastav djevičanskog maslinovog ulja. U radu je opisana građa i sastav ploda masline, kemijski sastav djevičanskog maslinovog ulja te prisutni endogeni enzimi. Prikazane su sve faze tehnološkog procesa prerade maslina u ulje te opisano djelovanje enzima u ovisnosti o različitim uvjetima tijekom prerade. Enzimskim reakcijama kataliziranim oksidoreduktazama PPO i POD narušava se kvaliteta maslinovog ulja oksidacijom triacilglicerola i fenolnih komponenti. Kvalitetnom kemijskom sastavu doprinose hidrolaze glukozidaze koje prevode hidrofilne fenolne tvari u manje hidrofilne oblike koji su topljivi u ulju i povećaju antioksidacijsku stabilnost ulja. Hidrolaze lipaze koje hidroliziraju triacilglicerole povećaju koncentraciju slobodnih masnih kiselina, di- i monoacilglicerola koji su supstrati za oksidoredukcijski enzim lipoksigenazu. U tehnološkom procesu proizvodnje endogeni enzimi su pod utjecajem različitih parametara što uvjetuje njihovu aktivnost te posljedično i kemijski sastav djevičanskog maslinovog ulja. The aim of this review is to investigate the influence of endogenous enzymes of olive fruit on the chemical composition of virgin olive oil. The structure and composition of the olive fruit, the chemical composition of virgin olive oil and the endogenous enzymes is presented. The activity of enzymes is described depending on different processing conditions. Enzymatic reactions catalyzed by oxidoreductases, PPO and POD impair the quality of olive oil by oxidation of triacylglycerol and phenols. Glycoside hydrolases contribute to quality of oil chemical composition by converting hydrophilic phenols into smaller forms soluble in oil and increase antioxidant stability of the oil. Lipase hydrolases that hydrolyze triacylglycerols increase the concentration of free fatty acids, di- and monoacylglycerols, which are substrates for the oxidoreducing enzyme lipoxygenase. In the technological process of production, endogenous enzymes are influenced by various parameters, which determines their activity and, consequently, the chemical composition of virgin olive oil.

Maslina (Olea Europea) je zimzelena vrsta koja uspijeva samo na umjereno toplim krajevima gdje je temperatura rijetko ispod 0 ° C. Plod masline u početku je zelen, a zatim prelazi u crno-ljubičastu boju. Postupcima prerade ploda maslina dobivamo djevičansko maslinovo ulje, a postupci uključuju: berbu, čuvanje ploda od berbe do prerade, čišćenja i pranja plodova, mljevenja i drobljenja, miješenja tijesta, separacije te bistrenja. Tim postupcima u djevičanskom maslinovom ulju su sačuvani važni sastojci koja druga ulja ne sadrže. Djevičansko maslinovo ulje je jedno od najpoznatijih ulja na svijetu i ima raznoliku primjenu. Koristi se kao začin za jela, kuhanje i prženje hrane, a zbog svojih ljekoviti svojstava i u medicinske svrhe. Olive (Olea Europea) is an evergreen species that thrives only in moderately warm regions where the temperature is rarely below 0 ° C. The fruit of the olive is initially green and then turns black-purple. Olive oil processing processes produce olive oil, and the procedures include: harvesting, storing the fruit from harvest to processing, cleaning and washing the fruit, grinding and crushing, malaxation, oil separation and clarifying. These procedures preserve important ingredients in virgin olive oil that other oils do not contain. Olive oil is one of the most famous oils in the world and has a variety of applications. It is used as a spice for meals, cooking and frying food, and because of its medicinal properties and for medicinal purposes.

Vinova loza, Vitis vinifera L., značajna je kultura Hrvatske, a proizvodi se na 19.824 hektara zemlje. Glavni proizvod ploda vinove loze je vino, a prilikom proizvodnje nastaje nekoliko nusprodukata uključujući sjemenke. Jedan od načina zbrinjavanja sjemenki je izdvajanje ulja, stoga je cilj ovog rada odrediti postoje li statistički značajne razlike u sastavu masnih kiselina i sterola takvog ulja između pojedinih sorti. Rezultati istraživanja pokazali su da sjeme sadrži 9,6-11,9 % vode, a ulja 8,3-12,8 %. Najzastupljenijemasne kiseline od svih uzoraka bile su linolna masna kiselina detektirana u udjelu od 61,5-67,8 %, zatim oleinska u udjelu 17,1-21,1 % te palmitinska s udjelom 8,9-11,9 %.Od fitosterola, u svim uzorcima detektiran je najveći udio β-sitosterola (74,36-81,14 %), zatim kampesterola (8,10-9,31 %) te stigmasterola (6,58-8,05 %). Između ispitivanih ulja iz sjemenki različitih sorti detektirana je statistički značajna razlika u udjelima masnih kiselina i fitosterola. Grape vine, Vitis vinifera L., is a significant agro-culture of Croatia, and is produced on 19.824 hectares of a land. Main product of vine is wine, and during its production occur several byproducts, including seeds. One method of seed treatment is oil extraction, therefore, purpose of this work was to determine statistically significant differences in fatty acid composition and phytosterols among oils produced from different varieties of grape. The results have shown that grape seed contains 9,6-11,9 % moisture and 8,3-12,8 % oil. The most common fatty acid among samples was linoleic fatty acid detected in the range of 61,5- 67,8 %, followed by oleic fatty acid in the range of 17,1-21,1 % and palmitic fatty acid in the range of 8,9-11,9 %. Regarding sterols, β-sitosterol was detected in the greatest content among all samples (74,36-81,14 %), followed by campesterol (8,10-9,31 %) and stigmasterol (6,58-8,05 %). The statistically significant difference was found between all samples of grapeseed oil from different sortiments in the amount of fatty acids and phytosterols.

Cilj ovog rada bio je usporediti kvalitetu DMU proizvedenog na tradicionalan i moderan način. Ispitivanje je provedeno na dva uzorka ulja proizvedena na području grada Hvara, te su im određeni osnovni parametri kvalitete i provedena je senzorska procjena. DMU proizvedeno na tradicionalni način bi se prema osnovnim parametrima kvalitete moglo svrstati u kategoriju djevičansko maslinovo ulje. DMU proizvedeno na moderni način im osnovne parametre kvalitete koji odgovaraju kategoriji ekstra djevičansko maslinovo ulje, no senzorska procjena je pokazala da ipak ne može biti uvršteno u tu kategoriju jer je uočen jedan defekt. The aim of this work was to compare the quality of virgin olive oil made with traditional and modern methods. The examination had been conducted on two samples of oil, originated and produced at the area of city of Hvar. Thereby, basic quality parameters had been specified and sensory evaluation was performed. Virgin olive oil produced with traditional methods could be considered as virgin olive oil due to the basic quality parameters. Virgin olive oil produced with modern methods has basic quality parameters that match the category of extra virgin olive oil, but sensory evaluation had shown that it cannot be included in that category since defect was detected.

Kako bi se utvrdilo koliko su maslinari na području Zadarske županije educirani o značaju pravilne prerade maslina, analizirano je 9 uzoraka djevičanskog maslinovog ulja prema osnovnim parametrima kvalitete. Svi uzorci prikupljeni su s područja Zadarske županije i svi sa godinom proizvodnje 2017./2018. Prema osnovnim parametrima kvalitete pokazalo se da je 6 od 9 uzoraka imalo minimalan stupanj hidrolitičkog i oksidacijskog kvarenja te poželjne senzorske karakteristike. Kod 2 uzorka zabilježene su senzorske mane koje ih svrstavaju u kategoriju djevičanskog maslinovog ulja, a kod jednog u kategoriju lampante. To determine whether the olive producers in Zadar region accepted the new ways of processing and preservation of virgin olive oil 9 samples were analyzed. All samples were from Zadar region and with the year of production 2017./2018. Analysis of main quality parameters showed that 6 out of 9 samples had no significant oxidative or hydrolytic degradation and had advisable sensory characteristics. 2 samples had sensory flaws that put them in category of virgin oil, and one sample had sensory defect that puts it in lampante category.

Djevičansko maslinovo ulje tradicionalno se koristi u mediteranskoj kuhinji i ulje je koje sadrži visoku koncentraciju antioksidanasa te ima pozitivan učinak na ljudsko zdravlje. Prirodni antioksidansi u djevičanskom maslinovom ulju su fenolni spojevi koji štite maslinovo ulje od oksidacijskih promjena te su odgovorni za specifična senzorska svojstva djevičanskog maslinovog ulja. Cilj ovo rada bio je odrediti utječe li zrelost ploda maslina na osnovne parametre kvalitete i na udjel polifenolnih spojeva. Osnovni parametri kvalitete, udio slobodnih masnih kiselina, peroksidni broj i K-brojevi, pokazuju stupanj hidrolitičkog ili oksidacijskog kvarenja u ulju te ne pokazuju značajno odstupanje u ovisnosti o indeksu zrelosti. U literaturi stoji da na udjel polifenola utječu sorta, klimatski uvjeti, uvjeti uzgoja, proizvodnje i skladišetnja, a u ovom radu se potvrdio i značajan utjecaj stupnja zrelosti ploda. Virgin olive oil is traditionally used in Mediterranean cuisine and is an oil that contains a high concentration of antioxidants and has a positive effect on human health. Natural antioxidants in virgin olive oil are phenolic compounds that protect olive oil from oxidative changes and are responsible for the specific sensory properties of virgin olive oil. The aim of this study was to determine the effect of maturity index on the basic quality parameters and concentration of polyphenolic compounds. The basic quality parameters, free fatty acids, the peroxide number, and the K-numbers show the degree of hydrolytic or oxidative degradation in the oil and do not show significant deviation depending on the maturity index. Many studies confirm that concentration of polyphenols depends on the variety, climatic conditions, conditions of breeding, production and storage and this study confirms the significant influence of the degree of fruit maturity.

Visoka koncentracija nutritivno vrijednih polifenolnih spojeva čine pogaču lana jako dobrom sirovinom za njihovu ekstrakciju. Cilj ovog rada bilo je izolirati i odrediti bioaktivne spojeve iz pogače lana upotrebom eutektičkih otapala i novih metoda ekstrakcije, kao bržih i ekološki prihvatljivijih postupaka. Kao najoptimalnije eutektičko otapalo pokazao se kolin klorid:urea:glicerol, a najveći udio fenolnih spojeva je ekstrahiran kombinacijom mikrovalova i ultrazvuka. Mikrovalnom ekstrakcijom detektirani su: sekoizolarikirezinol-diglukozid (SDG) (2.35 mg g-1), glukozid p-kumarinske kiseline (GPK) (4.13 mg g-1) te glukozid ferulinske kiseline (GFK) (1.94 mg g-1). Uz mikrovalno-ultrazvučno potpomognutu ekstrakciju, maksimalne izolirane koncentracije za SDG bile su 3.25 mg g-1, za GPK 4.34 mg g-1 i GFK 2.35 mg g-1, odnosno uspješno je ekstrahirano 15 % SDG-a, 42 % GPK-a te 45 % GFK-a u odnosno na koncentracije dobivene referentnom metodom, ali uz značajno kraće vrijeme trajanja procesa ekstrakcije. Potrebna su daljnja istraživanja u svrhu odabira najpogodnijeg eutektičkog otapala i optimiranja procesa ekstrakcije. High concentrations of bioactive polyphenolic compounds make flaxseed cake very good raw material for their extraction. The aim of this paper was to isolate and determine bioactive compounds from flaxseed cake using eutectic solvents and new extraction methods as faster and more environmentally friendly methods. Choline chloride: urea: glycerol was found as the most optimal eutectic solvent, and the higher yield of the phenolic compounds were extracted by a combination of microwaves and ultrasound. Using only microwave extraction the highest obtained results were: secoizolariciresinol-diglucoside (SDG) (2.35 mg g-1), p-coumaric acid glucoside (GPK) (4.13 mg g-1) and ferulic acid glucoside (GFK) (1.94 mg g-1). With ultrasonic microwave-assisted extraction, the maximum isolated concentration of SDG was 3.25 mg g-1, GPK 4.34 mg g-1 and GFK 2.35 mg g-1.Compared with reference method, 15% SDG was successfully extracted, 42% of GPK and 46% of GFK, but with significantly shorter processing time. Further research is required to select the most suitable eutectic solvent and optimize the extraction process.

U posljednjih nekoliko godina na hrvatskom tržištu ponovno oživljava uzgoj i proizvodnja ulja industrijske konoplje koje odskače od drugih sličnih proizvoda po specifičnom sastavu masnih kiselina. Cilj ovog rada bio je odrediti tehničko–tehnološka svojstva sjemena i sastav masnih kiselina različitih uzoraka konoplje. Analize su provedene na sjemenu, pogači te ulju konoplje proizvedenom hladnim prešanjem iz sjemena uzgojenog 2016. godine na području Republike Hrvatske od domaćih proizvođača. Prema dobivenim podacima u analiziranim uzorcima konoplje najzastupljenije su linolna (56,1 – 56,3 %), oleinska (13,7 - 16,0 %) te α-linolenska masna kiselina (13,3 - 16,3 %), a udio ulja u analiziranom sjemenu kretao se od 31,7 do 35,3 %. Udio ulja koji je zaostao u analiziranoj pogači iznosio je 14,3 %. Analize su pokazale da je udio slobodnih masnih kiselina za analizirane uzorke ulja bio u skladu sa Pravilnikom (2012b), dok je vrijednost peroksidnog broja za jedan uzorak ulja bila viša od vrijednosti propisane Pravilnikom (2012b). Over the last few years, the Croatian market has resumed cultivation and production of industrial hemp oil, which differs from other similar products with the specific composition of fatty acids. The aim of this paper was to determine the quality parameters of seeds and fatty acid composition of different hemp oils. Analysis were conducted on seeds, cake and cold-pressed hemp oil from seed produced in 2016 in the Croatia from domestic producers. According to the data obtained in the analyzed samples the most common are linoleic (56,1 - 56,3 %), oleic (13,7 - 16,0 %) and α-linolenic fatty acid (13,3 - 16,3 %) and the yield of oil in the analyzed seed ranged from 31,7 to 35,3 %. The percentage of residual oil in cake was 14,3 %. The analysis showed that the proportion of free fatty acids for analyzed oil samples was in accordance with the Protocol (2012b), while the peroxide value for one oil sample was higher than the values prescribed by the Protocol (2012b).

Lan se smatra najbogatijim biljnim izvorom lignana prema visokom sadržaju sekoizolarikirezinol diglukozida (SDG), uz manje količine fenolnih kiselina. Pogača lana, koja je nusproizvod nakon prešanja, može poslužiti kao dobra sirovina za njihovu ekstrakciju. Cilj ovog rada bio je odrediti koncentracije lignana i fenolnih kiselina u pogači lana te ispitati utjecaj različitih otapala na njihovu izolaciju. Provedena je ekstrakcija na planskoj tresilici s dva različita otapala (70 % MetOH + 30 % 0,1 M NaOH i 70 % MetOH + 30 % 1 M NaOH). Dobiveni rezultati pokazali su da je najveća koncentracija SDG-a ekstrahirana s otapalom manje molarnosti NaOH, a za ekstrahiranje fenolnih kiselina kao učinkovitije otapalo pokazalo se ono veće molarnosti NaOH. Flaxseed is considered the richest plant source of lignans by high content of secoisolariciresinol diglucoside (SDG), with fewer amounts of phenolic acids. Flaxseed cake, as a by-product after oil pressing, can serve as good source for their extraction. The aim of this study was to determine the concentrations of lignans and phenolic acids in the flaxseed cake and to examine the influence of different solvents on their isolation. Extraction was performed on a planar shaker with two different solvents (70% MetOH + 30% 0.1 M NaOH and 70% MetOH + 30% 1 M NaOH). The results obtained showed that the largest concentration of SDG was extracted with a less molar solvent of NaOH, and the higher molar solvent of NaOH has shown more efficient for the phenolic acids.

Pogaču lana odlikuju visoke koncentracije polifenolnih spojeva, prvenstveno lignana, te ona može poslužiti kao dobra sirovina za njihovu ekstrakciju. Cilj ovog rada bio je izolirati i odrediti bioaktivne spojeve iz pogače lana dobivene nakon hladnog prešanja koristeći standardne metode ekstrakcije te ispitati utjecaj mikrovalova i ultrazvuka na ekstraktibilnost bioaktivnih spojeva. Standardnom metodom iz pogače su izolirani i tekućinskom kromatografijom detektirani lignani: sekoizolarikirezinol (7,76 mg g-1), pinorezinol (2,33 mg g-1) i matarezinol (1,43 mg g-1) te manja količina fenolnih kiselina: pkumarinska (0,57 mg g-1), ferulinska (0,34 mg g-1) siriginska (0,06 mg g-1) i sinapinska kiselina (0,04 mg g-1). Primjenjene metode ultrazvučno-mikrovalno potpomognute ekstrakcije nisu dale zadovoljavajuće rezultate. Potrebna su daljnja istraživanja kako bi se metoda optimirala i jasnije utvrdili utjecaji ultrazvuka i mikrovalova na molekule lignana i fenolnih spojeva. Flaxseed cake is characterised by high concentrations of polyphenolic compounds, particularly lignans and it can serve as sources for their extraction. The aim of this study was to isolate and identify the bioactive compounds from flax cake obtained after cold pressing using standard extraction methods, and examine the effect of microwaves and ultrasound on the extractability of bioactive compounds. Using standard method for extraction following compounds were isolated and determined with HPLC: lignans - Secoisolariciresinol (7,76 mg g-1), pinoresinol (2,33 mg g-1) and mataresinol (1,43 mg g-1) and smaller amounts of phenolic acids - p-coumaric acid (0,57 mg g-1), ferulic (0,34 mg g-1) syringic (0,06 mg g-1) and sinapinic acid (0,04 mg g-1). Applied methods for ultrasound-microwave assisted extraction did not provide clear results. Further research is needed in order to optimize the methods and clearly identify the effects of ultrasound and microwaves on molecules of lignans and phenolic compounds.

Soja, latinskog naziva Glycine max (L.) Merrill, jedna je od vodećih svjetskih poljoprivrednih kultura, čije se sjeme koristi kao izvor jestivih ulja, proteina i fitokemikalija. Cilj ovog rada je bio utvrditi utjecaj kultivara soje dobivenih procesom oplemenjivanja na udjel i sastav tokoferola sirovog sojinog ulja. U radu su provedena ispitivanja na uzorcima sojinog sjemena i sirovog sojinog ulja dobivenog postupkom ekstrakcije po Soxhletu. Rezultati su pokazali da kultivar značajno utječe na osnovne parametre kvalitete sjemena soje, na udjel pojedinačnih i ukupnih tokoferola i na udjel linolne, oleinske, palmitinske, α-linolenske, stearinske, arahidonske, eikosenske i behenske masne kiseline. Najzastupljenija masna kiselina u svim uzorcima je bila esencijalna omega-6 linolna sa najvećom vrijednosti u uzorku S8. Među tokoferolima, γ–tokoferol je bio nazastupljeniji u svim uzorcima, gdje uzorak S10 sadrži najviše ukupnih tokoferola. Najveći udjel ulja je pronađen kod uzoraka S1 i S3, a uzorak S8 sadrži najveću količinu proteina. Najveću vrijednost esencijalne omega-3 masne kiseline ima uzorak S3. Soybean, Latin Glycine max (L.) Merrill, is one of the leading cultures which seed is used as a source of edible oil, protein and phytochemicals. The aim of this study was to determine the influence of new cultivars developed by breeding on the composition and content of tocopherols of crude soybean oil. Analysis were performed on soybean seed and crude soybean oil samples. Cultivar had a significant impact on the main parameters of seed quality, tocopherol content and composition of their isomers, fatty acids such as palmitic, stearic, oleic, linoleic, α-linolenic, arachidic, eicosenic and behenic. The dominant fatty acid in all samples was linoleic and sample S8 has the highest value. The dominant tocopherol of all analyzed oils was γ-tocopherol, where sample S10 contains the highest value of total tocopherols. The largest share of oil was found in samples S1 and S3. Sample S8 contains the highest amount of protein and sample S3 had the highest amount of esential omega-3 fatty acid.

Mak (Papaver somniferum L.) je kultivirana biljka koja se sadi radi proizvodnje opijuma, jestivog ulja i sjemena koje je bogato linolnom (ω-6) masnom kiselinom. Ovo istraživanje je nastavak rada iz 2014. godine, a imalo je za cilj odrediti udio vode, ulja i sastava masnih kiselina u dvanaest uzoraka sjemena maka uzgojenih 2015. godine na eksperimentalnom polju Agronomskog fakulteta u Zagrebu. Određeni su osnovni parametri kvalitete te sastav masnih kiselina putem plinske kromatografije. Udio vode (5,2 – 5,8%) i ulja (40,6 – 46,4%) je bio u skladu s podacima navedenim u literaturi. Dobiveni podaci o kvalitativnom sastavu masnih kiselina također su bili u skladu s literaturnim navodima, dominantna masna kiselina u svim ispitivanim uzorcima ulja bila je linolna (66,4 – 73,4%), zatim značajni udio čine oleinska (12,9 – 21,7%) i palmitinska (8,9 – 10,1%), dok stearinske (1,9 – 2,7%) i linolenske masne kiseline (0,7 – 1,1%) ima najmanje. Sorta koja se ističe s najvećim udjelom ulja je Gornji Bogičevci (46,4%). Poppy (Papaver Somniferum L.) is a cultivated plant grown for the production of opium, edible seeds and seed oil rich in linoleic (ω-6) fatty acid. This study is a continuation of the work from 2014 and it was aimed to determine the content of water, oils and fatty acid composition in twelve samples of poppy seedwhich were grown on experimental field of the Faculty of Agriculture in Zagreb. Basic quality parameters of poppy seed and fatty acid composition were determined via gas chromatography. Moisture (5.2 – 5.8%) and oil (40.6 – 46.4%) contents were in accordance to the data from the literature. The results of fatty acid composition were likewise in accordance with the data from the literature, the main fatty acid in all poppy seed oils was linoleic (66.4 – 73.4%), followed by oleic (12.9 – 21.7%) and palmitic acid (8.9 – 10.1%). The lowest values were with stearic (1.9 – 2.7 %) and linolenic acid (0.7 – 1.1%). The variety with the highest oil content was Gornji Bogičevci (46.4%).

Cilj ovog rada bio je odrediti udio i sastav sterola u sojinom ulju. Koristili smo 11 uzoraka sjemena različitih kultivara soje, uzgojenih 2015. godine na eksperimentalnom polju Agronomskog fakulteta u Zagrebu. Ulje je proizvedeno ekstrakcijom po Soxhletu uz heksan kao organsko otapalo. Udio i sastav sterola smo odredili metodom plinske kromatografije. Udio ukupnih sterola u uzorcima sojinog ulja je u rasponu od 3211 do 5162 mg/kg, dok je najzastupljeniji sterol u svim uzorcima β-sitosterol. U ulju su, također, detektirani kampesterol, kampestanol, stigmasterol, ∆5-avenasterol, ∆7-stigmasterol i ∆7-avenasterol. The aim of this study was to determine sterols content and composition in crude soybean oil. We used 11 seed samples of different soybean cultivars grown on the experimental fields of the Faculty of Agriculture in Zagreb in 2015. Oil was produced by the Soxhlet extraction, using hexane as an organic solvent. We determined sterols content and composition using the method of gas chromatography. Content of overall sterols in samples of soybean oil are within range between 3211 and 5162 mg kg-1, while the most common sterol in all samples is β-sitosterol. Other sterols detected in oil were campesterol, campestanol, stigmasterol, ∆5-avenasterol, ∆7-stigmasterol and ∆7-avenasterol.