<p>Cilj istraživanja u okviru ove teze je bio da se ispita mogućnost upotrebe pogače uljane tikve golice, nusproizvoda pri proizvodnji devičanskog ulja, za proizvodnju namaza sličnom kikiriki maslacu, kako po spolja&scaron;njem izgledu i teksturi, tako i po reolo&scaron;koj stabilnosti. Namazi su formulisani tako da imaju visok sadržaj omega-6 i omega-3 masnih kiselina, uz njihov izbalansirani odnos prema principima kvalitetne ishrane i preporukama nutricionista, prijatna senzorska svojstva i dobru oksidativnu stabilnost. Upotrebom dvo-faktorskog eksperimentalnog dizajna na pet nivoa i metode odzivnih povr&scaron;ina, kao i statističke analize podataka, izvr&scaron;ena je optimizacija tehnolo&scaron;kog procesa za proizvodnju namaza sa definisanim poželjnim funkcionalnim karakteristikama proizvoda sa nutricionističkog i teksturalnog aspekta. Rezultati su pokazali da je pogača (na 100 g proizvoda) veoma bogata mineralima, uz izuzetno visok sadržaj fosfora, gvožđa, magnezijuma i cinka koji prevazilazi 100% dnevnih potreba prema Pravilniku (2004), a takođe sadrži i velike količine mangana, kalijuma i bakra, te opravdava valorizaciju iste za proizvodnju nutritivno visokovrednog namaza. Devičansko tikvino ulje, poreklom iz pogače, je znatno doprinelo i nutritivnoj vrednosti namaza, budući da je isto bogato omega-6 masnim kiselinama (51.04%) i &gamma;-tokoferolima (704 mg/kg). Konopljino ulje je veoma uticalo na senzornu ocenu namaza, pre svega na ukus i teksturu, kao i na oksidativnu stabilnost. Ustanovljeno je da rok trajanja namaza zavisi od stepena oksidacije ulja u njegovom sastavu, pre svega od količine i kvaliteta konopljinog ulja, i može biti najduže do 6 meseci pri sobnoj temperaturi čuvanja. Utvrđeno je da izdvajanje ulja na povr&scaron;ini namaza zavisi od količine dodatog stabilizatora, a najbolji rezultati su postignuti dodatkom 1.6% stabilizatora. Optimalna vrednost za dobijanje namaza najprihvatljivijeg nutritivnog i senzornog kvaliteta, oksidativne stabilnosti i teksture, je sadržaj stabilizatora od 1.2-1.4% uz 40-60% dodatog konopljinog ulja u masnu fazu proizvoda. Svi proizvedeni namazi su sadržali esencijalnu omega-3 masnu kiselinu uz mogu&scaron;nost deklarisanja kao &bdquo;izvor omega-3 polinezasićenih masnih kiselina&ldquo;, od kojih su pojedini uzorci imali vrlo visok sadržaj (0.98 i 1.24 g) po konzumnoj jednici (15 g). Svi proizvedeni namazi su sadržali i omega-6 masne kiseline, od kojih su pojedini uzorci imali visok sadržaj po konzumnoj jedinici (2.5-3 g), uz mogućnost deklarisanja kao &bdquo;izvor omega-6 polinezasićenih masnih kiselina&ldquo;. Svi namazi (izuzev jednog) su imali odlično izbalansiran odnos između omega-6 i omega-3 masnih kiselina (2-3:1).</p> / <p> The goal of this research was to investigate the possible use of hull-less pumpkin seed oil press cake, a by-product of the pumpkin seed oil pressing process, for the manufacturing of a spread. The spread would be similar to a peanut butter, in appearance, texture and rheological stability. Spreads were formulated in such way that they would have pleasant sensory attributes, good oxidative stability with a high omega-6 and omega-3 fatty acids content, while providing their balanced ratio based on modern healthy food principles as recommended by nutritionists. Optimization of the spread manufacturing technology was conducted based on the results of the two factorial experimental design on five levels using response surface methodology and statistical analysis (ANOVA). Desirable functional characteristics of the spreads were defined based on nutritional and textural attributes. Results have shown that pumpkin seed oil press cake (per 100 g) is very rich in minerals, especially phosphorus iron, magnesium and zinc that exceeds recommended daily intake (Pravilnik, 2004) over 100%. In addition, it contains high amounts of manganese, potassium and copper, which justifies the use of the seed oil press cake for investigation of the possibility for its use in nutritious spread manufacturing. Cold pressed hull-less pumpkin oil significantly contributed to the nutritional value of the spreads, since it is rich in omega-6 fatty acids (51.04%) and &gamma;-tocopherols (704 mg/kg). Hemp oil had a significant effect on the sensory evaluation of the spreads, primarily on the taste and texture, as well as the oxidative stability of the spreads. It was confirmed that the shelf life of the spreads depended on the oxidation of the oils present in the spread, and primarily depended on the hemp oil quantity and quality. All spreads had a shelf life of maximum 6 months at ambient temperature. It was also confirmed that oil separation on the spreads&rsquo; surface depended on the amount of added stabilizer, where the best results were achieved with the addition of 1.6% stabilizer. Considering nutritional value, sensory evaluation, oxidative stability and texture, the optimal spreads were made using the stabilizer at 1.2-1.4% and hemp oil at 40-60% added to the fatty phaze of the spread. All prepared spreads contained omega-3 essential fatty acid that could be declared as a &ldquo;source of omega-3 polyunsaturated fatty acids&ldquo;. Few samples had a very high content of omega-3 fatty acids (0.98 and 1.24 g) per serving size 15 g). In addition, all prepared spreads contained omega-6 fatty acids, where some samples had a high content of omega-6 fatty acids per serving size (2.5-3 g), and could be declared as a &ldquo;source of omega-6 polyunsaturated fatty acids&ldquo;. All prepared spreads (except one) had a well balanced ratio between omega-6 and omega-3 fatty acids (2-3:1).</p>

<p>Jedno od specijalnih jestivih ulja koje se proizvodi isključivo mehaničkim postupkom i koje se može uvrstiti u grupu funkcionalnih prehrambenih proizvoda je ulje semena tikve. Ovo ulje je veoma atraktivno za potro&scaron;ace, pre svega zbog svoje karakteristične arome, visoke nutritivne vrednosti i dokazanog blagotvornog delovanja na zdravlje. Cilj istraživanja u okviru ove teze je bio da se izvr&scaron;i karakterizacija senzorsko nutritivnog kvaliteta i oksidativne stabilnosti hladno presovanih i devičanskih ulja tikve sa trži&scaron;ta, ispita uticaj termičke obrade semena na kvalitet, nutritivnu vrednost i održivost devičanskog tikvinog ulja i da se defini&scaron;u senzorska svojstva i održivost hladno presovanog ulja semena tikve. U cilju karakterizacije ulja ispitivanja su sprovedena na većem broju uzoraka hladno presovanih i devičanskih ulja semena<br />tikve nabavljenih neposredno, slučajnim izborom sa domaćeg i inostranog trži&scaron;ta. Definisana su osnovna svojstva i najbitnije kvalitativne razlike između ove dve kategorije ulja proizvedenih različitom tehnologijom. Iako se proizvode iz iste sirovine tikvina ulja se međusobno bitno razlikuju po brojnim kvalitativnim, a naročito senzorskim svojstvima (ukus, miris, aroma i boja) &scaron;to može da stvori zabune kod<br />potro&scaron;aca. Ispitivanjima uticaja različite termičke obrade semena utvrđeno je da proces pečenja mlevenog materijala neposredno pre presovanja bitno utiče na kvalitativna svojstva i održivost devičanskog ulja. Termička obrada mlevenog semena pri temperaturi u interval od 90 do 130 ^oC i vremenu od 30 do 70 min pokazala je različit uticaj na senzorski kvalitet, sadržaj bioaktivnih komponenata i oksidativnu stabilnost ulja ispoljavajući kako negativan, tako i pozitivan efekat. U delu istraživanja vezanih za definisanje senzorskih svojstava i određivanje održivosti ulja izdvojenog postupkom hladnog presovanja osu&scaron;enog semena tikve na pužnoj presi, ustanovljeno je da se najkvalitetnije ulje dobije pri prvom presovanju, buduci da je aroma ulja najbolja, pri tom su kiselinski i peroksidni broj najmanji, a indukcioni period najduži. Ovo se potvrdilo, kako pri presovanju samo semena golice, tako i pri presovanju golice sa dodatkom semena sa ljuskom. Promene najbitnijih pokazatelja u cilju odredivanja održivosti ulja praćene su periodično u trajanju od 2 godine. U<br />tom periodu do&scaron;lo je do izvesnog pogor&scaron;anja senzorskog kvaliteta ulja, određenog porasta kiselinskog i peroksidnog broja, kao i do smanjenja indukcionog perioda. Medutim, bez obzira na intenzitet nastalih promena, ulja su odgovarala svim zakonskim normama kvaliteta i nakon dve godine čuvanja. Ipak, radi obezbeđenja vrhunskog kvaliteta za rok trajanja hladno presovanih ulja semena tikve golice može se preporuciti period najvi&scaron;e do godinu dana.</p> / <p> Pumpkin seed oil is one of the specialty oils produced only by mechanical procedure and can be classified in the group of functional food products. This oil is very attractive (interesting) for the consumers first of all for its characteristic flavour, high nutritive value and proved beneficial effect on health. The aim of the investigations in the scope of this thesis was to characterize the sensoric-nutritive quality and oxidative<br /> stability of cold pressed and virgin pumpkin seed oils from the market, to investigate the effect (influence) of heat treatment of seed on quality, nutritive value and stability of virgin pumpkin seed oil and to define the sensory characteristics and stability of cold pressed pumpkin seed oil. Aiming to characterize the oil, a number of cold pressed and virgin pumpkin seed oil samples, randomly taken from the domestic and foreign market, were investigated (analyzed). The basic characteristics and most important qualitative differences between these two categories of oils produced applying different technologies were defined. Both types of pumpkin seed oils are produced from the same raw material, however, they differ significantly regarding a number of<br /> quality, and expecially sensory proterties (taste, odour, flavour and colour), so the consumers may become embarrassed. Investigating the influence of different heat treatment of seed, it was found that the roasting of ground material before the pressing affects significantly the quality characteristics and stability of virgin oil. The heat treatment of ground seed at temperatures 90 to 130 &deg;C, for 30 to 70 min, showed different influence on sensory quality, content of bioactive components and oxidative stability of oil, exhibiting both negative and positive effect. In the part dealing with the defining of sensory characteristics and stability determination of oil obtained by cold pressure of dried pumpkin seed on screw press, it was found that most quality oil was obtained by the first pressing process, the oil flavur is the best, with lowest acid and peroxide value, and the induction period is the longest. This was confirmed by pressing both hull-less pumpkin and hull-less with the addition<br /> of pumpkin seed with hull. The most important characteristics for oil stability were<br /> followed for two years. In this period a certain deterioration of sensory quality was found, the acid and peroxide value increased, and the induction period decreased. However, disregarding the intensity of changes, the oil samples are in accordance with all legal quality normatives even after two years from the production date. However, in order to maintain the high (first-class) quality of cold pressed oil of hull-less pumpkin seed, the recomended period for the shelf-life of oil is one year.</p>

<p>Osnovni cilj ovog istraživanja je utvrđivanje mogućnosti proizvodnje funkcionalnog niskoenergetskog prehrambenog namaza na bazi bra&scaron;na od semena tikve golice i hidrokoloida ugljenohidratnog porekla.<br />Utvrđivanju ove mogućnosti prethodilo je potpuno karakterisanje i definisanje sastavnih komponenti namaza. To su bra&scaron;no od semena tikve golice i prehrambeni hidrokoloidi na bazi vlakana. Bra&scaron;no od semena tikve golice analizirano je radi određivanja njegovih fizičko&ndash;hemijskih karakteristika, funkcionalnih svojstava, mikrobiolo&scaron;ke ispravnosti i mikrostrukturalne prirode. Analizama bra&scaron;na stečen je uvid u fizičke, nutritivne i mikrobiolo&scaron;ke karakteristike i u svojstva pona&scaron;anja, s ciljem utvrđivanja mogućnosti primene bra&scaron;na od semena tikve u daljem radu. Takođe, ispitane su dve vrste hidrokoloida ugljenohidratnog porekla metodom mikrostrukturalne analize, metodom određivanja raspodele veličina čestica, reolo&scaron;kim određivanjima i teksturalnim karakterisanjem sistema. Cilj ovog ispitivanja je definisanje vrste i koncentracije vlakana u gel strukturi hidrokoloida, koja ima sposobnost da ostvari ulogu nosača bra&scaron;na, odnosno kontinualne faze u namazu. Time je predviđeno i pona&scaron;anje ugljenohidratnih hidrokoloida u prehrambenom sistemu tipa namaza.<br />Nakon definisanja sastavnih komponenti, radi utvrđivanja optimalnih svojstava namaza, analizirani su namazi sa različitom vrstom i koncentacijom vlakana u gel sistemu i različitim udelom primenjenog hidrokoloida u sastavu namaza. Pri ispitivanju značajnosti uticaja promenljivih faktora na svojstva dobijenih namaza kori&scaron;ćena je metoda planiranja eksperimenta (DOE&ndash;design of experiment) u okviru koje je primenjen potpuni faktorijalni dizajn. Takođe, međusobna linearna zavisnost<br />između pojedinih promenljivih određena je metodom korelacije sa ciljem utvrđivanja povezanosti parametara senzorske analize sa instrumentalno određenim karakteristikama.<br />Cilj objedinjenja svih analiza je definisanje sastava namaza optimalnih svojstava i formulacija niskoenergetskog prehrambenog namaza na bazi bra&scaron;na od semena tikve.<br />Na osnovu prikazanih rezultata istraživanja u okviru ove doktorske disertacije izvedeni su zaključci da je bra&scaron;no od semena tikve golice nutritivno i biolo&scaron;ki vrlo vredna sirovina dobre održivost, bez patogenih mikroorganizama i da predstavlja pogodnu sirovinu za proizvodnju namaza. Takođe, hidrokoloid Vivapur MCG 611F se odlikuje<br />povoljnijim reolo&scaron;kim i teksturalnim svojstvima od hidrokoloida Vitacel WFG HS73, jer tiksotropno protiče, ima veći stepen uređenosti i povezanosti strukture sa izraženom elastičnom prirodom koja mu omogućava manju podložnost deformacijama i čini ga pogodnim za proizvodnju namaza.<br />Na osnovu analize uticaja promenljivih faktora, koji se odnose na sastav namaza, zaključeno je da posmatrani namazi predstavljaju realne reolo&scaron;ke sisteme i da sastav namaza izraženo utiče na njihove reolo&scaron;ke, teksturalne i senzorske osobine.<br />Na osnovu sprovedenih istraživanja zaključuje se da je moguća proizvodnja niskoenergetskog namaza na bazi bra&scaron;na od semena tikve golice. Pri tome namaz treba da sadrži 80% MCG zamenjivača masti (na masu namaza) koncentracije hidrokoloidnog gela 7% i 20% bra&scaron;na od semena tikve golice (na masu namaza). Namaz optimalnih svojstava je polidisperzan sistem sa uređenom strukturom u<br />kojoj su čestice primenjene količine bra&scaron;na uklopljene u kontinuiranu mrežu hidratisanih MCG vlakana i potpuno obložene dostupnom količinom zamenjivača masti. Zahvaljujući takvoj organizaciji i strukturi sistema optimalni namaz ispoljava dobre reolo&scaron;ke karakteristike, optimalnu mazivost, dobro prijanjanje na povr&scaron;inu i laku manipulaciju namazom tokom proizvodnje i tokom primene. Dobijeni namaz predstavlja nutritivno vredan proizvod koji se na osnovu sastava i zdravstvenog uticaja komponenti može svrstati u funkcionalne prehrambene proizvode.</p> / <p>The main objective of this study was to determine the possibility of production the low-fat functional food spreads based on flour of pumpkin seed and carbohydrate<br />hydrocolloids.<br />That included complete characterization of components of the spreads, the flour of hull&ndash;less pumpkin seed and fiber based food hydrocolloids. Flour of pumpkin seed was analyzed in order to determine its physico&ndash;chemical characteristics, functional characteristics, microbiological safety and microstructural nature. These analyses of flour defined the physical, nutritional and microbiological characteristics and behavior of flour, with the aim of determine the possibilities of its application in further work.<br />Also, two types of carbohydrate based hydrocolloids were examined by microstructural aspect, by particle size distribution, rheological determinations and textural characterization. The aim of these analysis was to define the type and concentration of fibers in the gel structure of hydrocolloids, which has the ability of to flour carrier and the role of continuous phase in the spread. This predicted<br />the behavior of carbohydrate based hydrocolloids in the food system such as spreads.<br />The determination of main components of the spreads was followed by determination of optimal properties of the spreads, which included analysis of spreads with different type and concentrations of fibers in the gel system and the<br />different amount of the applied hydrocolloid. To determine the significance of the influence of variable factors on the properties of the obtained spreads, the method of design of experiment (DOE) was used, with applied full factorial design. Also, correlation between certain sensory and instrumentally determined parameters was defined.<br />The aim of all analysis was to define the composition of the spread with optimal properties and to formulate the low&ndash;fat food spread based on flour of pumpkin seed<br />Based on the results obtained within this doctoral thesis, it was concluded that the flour of pumpkin seed cake is nutritionally and biologically very valuable raw material<br />with good sustainability, without pathogenic microorganisms, thus it is a suitable raw material for the production of spread. Also, Vivapur MCG 611F was characterized as hydrocolloid with better rheological and textural properties than the hydrocolloid Vitacel WFG HS73, because of its thixotropic flow properties, higher degree of<br />networking and pronounced elastic nature of structure that provides lower susceptibility to deformation and makes it suitable for the production of spread.<br />Based on the influence of variable factors, related to the composition of spreads, it was concluded that the observed spreads were real rheological systems and that the<br />composition of spreads signifficantly influenced on their rheological, textural and sensory characteristics. Obtained resultes of this research suggested that the production of low&ndash;fat food spread based on flour of pumpkin seed is possible. This spread contains 80% of MCG 611F fiber based hydrocolloid ( on the mass of the spread) with gel concentration of 7% and 20% of flour of pumpkin seed cake ( on the mass of the spread). The spread with optimal properties is poydisperse system with compact structure in which the flour particles are incorporated into continious network of hydrated MCG fibers and completly coated with avaliable amount of fat relacer. Due to this organization and structure of the system, optimal spread exhibits good properties for manipulation during production and application, such as good rheological characteristics, optimal spreadability and good adhesion to the surface. Obtained spread is nutritionaly valuable food product which can be classified into functional food product based on the composition and health inffluance.</p>

<p style="text-align: justify; ">Hladno presovano ulje semena uljane tikve je&nbsp;proizvod specifičan za Srbiju, za razliku od zemalja u regionu koje imaju dugu tradiciju proizvodnje&nbsp;devičanskog tikvinog ulja.&nbsp;Tokom postupka hladnog presovanja sirovogosu&scaron;enog&nbsp;semena uljane tikve na pužnoj presi&nbsp;temperatura izdvojenog ulja ne prelazi 50 ^oC, &scaron;to se&nbsp;odražava na fizičko-hemijske, nutritivne i senzorne&nbsp;karakteristike kao i na oksidativnu stabilnost i&nbsp;antioksidativni potencijal ovog ulja.&nbsp;U cilju &scaron;to bolje karakterizacije ovog proizvoda na&nbsp;na&scaron;em trži&scaron;tu, ispitan je kvalitet hladno presovanog&nbsp;tikvinog ulja poreklom iz semena vi&scaron;e različitih&nbsp;slobodnooplodnih sorti i F1 hibrida, golosemenih i&nbsp;uljanih tikvi sa ljuskom, koje uspevaju u na&scaron;oj&nbsp;zemlji.&nbsp;Hladno presovano ulje semena tikve odlikuju&nbsp;specifične senzorne karakteristike: pored izuzetno&nbsp;blage arome, mirisa na sirovo seme tikve i ukusa&nbsp;koji podseća na meso tikve, ovo ulje se posebno&nbsp;izdvaja po boji koja je kod ispitivanog ulja bila&nbsp;svetlo-smedja do crvenkasta. Prema senzornim&nbsp;karakteristikama (naročito boji) izdvojili su se uzorci ulja poreklom iz semena austrijskih hibrida. Na&nbsp;osnovu sastava masnih kiselina ovo ulje pripada olinsko-linolnom tipu, &scaron;to ga svrstava u nutritivno&nbsp;veoma vredna biljna ulja, čemu doprinosi i visok&nbsp;sadržaj gama-tokoferola, koji je dominantan u&nbsp;tikvinom ulju. Određivanje sastava i sadržaja sterola je posebno bilo značajno kada je u pitanju hladno&nbsp;presovano tikvino ulje s obzirom da nema&nbsp;literaturnih podataka na tu temu. U ispitivanim&nbsp;uzorcima su bili dominantni delta-7 steroli, a određen je i izuzetno visok sadržaj skvalena, koji&nbsp;ima veoma važnu biolo&scaron;ku funkciju. Ispitivano ulje je posedovalo dobar antiradikalski potencijal, koji je&nbsp;bio u snažnoj linearnoj zavisnosti sa sadržajem fenolnih materija. Ulje dobijeno ekstrakcijom iz&nbsp;pogače, koja je zaostala nakon hladnog presovanja&nbsp;semena, posedovalo je veći antiradikalski potencijal&nbsp;u odnosu na hladno presovano &scaron;to je rezultat&nbsp;sadržaja fenolnih materija u većem procentu i ne&scaron;to&nbsp;nižeg sadržaja tokoferola u odnosu na hladno<br />presovano ulje.</p> / <p> Cold-pressed pumpkin oil is a product specific<br /> to Serbia, given that other countries in the<br /> region traditionally produce virgin pumpkin oil.<br /> In the process of cold pressing raw-dried<br /> pumpkin seeds by screw press, the<br /> temperature of extracted oil does not exceed<br /> 50oC, which affects physical, chemical,<br /> nutritional and sensory characteristics of this<br /> oil, as well as its oxidative stability and<br /> antiradical capacity.<br /> For the purpose of more precise<br /> characterization of this product in the domestic<br /> market, the quality of cold pressed oil from<br /> seeds of many free breeding varieties and F1<br /> hybrids &ndash; of both naked and husk seed<br /> pumpkins being grown in our country &ndash; was<br /> examined.<br /> Specific sensorial properties: light brown to<br /> reddish color, mild aroma, a smell similar to<br /> that of raw pumpkin seeds and a taste<br /> resembling that of pumpkin pulp are<br /> characteristic for this oil. As for sensory<br /> characteristics, the samples of oil from<br /> Austrian hybrid seeds, stood out. On the basis<br /> of fatty acid content, this oil belongs to the<br /> oleic-linoleic type, meaning it is a highly<br /> nutritional vegetable oil, which is also due to<br /> high levels of dominant gamma-tocopherol. Determination of the types and content of</p> <p> sterols was particularly important, given that<br /> there are no data specific to cold-pressed<br /> pumpkin oil in the literature. Delta-7 sterols are<br /> the most dominant sterols in examined oil<br /> samples and also very high content of<br /> squalene was found, which a compound with<br /> an important biological function is. The oil has<br /> an excellent antiradical capacity, showing a<br /> strong linear correlation with the amounts of<br /> phenolic compounds. Oil extracted from the<br /> cake, left over after the cold pressing of<br /> pumpkin seeds, had greater antiradical<br /> capacity than the samples of cold pressed oil,<br /> due to higher percentage of phenolic<br /> compounds and a slightly lower content of<br /> tocopherols compared to cold pressed oil.</p>

<p>U radu su prikazani eksperimentalni rezultati natkritične ekstrakcije etarskog ulja bobica<br />kleke (<em>Juniperus communis</em> L.) i ulja iz semena uljane tikve golice (<em>Cucurbita pepo</em> L.). Ispitan je uticaj pritiska, temperature, stepena usitnjenosti čestica i protoka natkritičnog<br />ugljendioksida na promenu prinosa ulja sa vremenom. U cilju poređenja, usitnjeno seme uljane tikve ekstrahovano je i u ekstraktoru većih dimenzija, NOVA-SWISS, High<br />pressure extraction plant, kao i heksanom i petroletrom u ekstraktoru tipa Sokslet.<br />Praćena je i promena kvaliteta ekstrakata sa vremenom: u etarskom ulju kleke, GC-FID i GC-MS metodama, određen je relativni sadržaj 50 terpenskih jedinjenja i sve komponente ulja su svrstane u 5 osnovnih grupa (monoterpene, seskviterpene, oksidovane monoterpene, oksidovane seskviterpene i ostale komponente). U tikvinom ulju ekstrahovanom natkritičnim ugljendioksidom određen je masnokiselinski sastav GC-MS analizom, sadržaj tokoferola HPLC analizom, sterola i skvalena GC-MS metodom. Određeni su uslovi koji favorizuju ekstrakciju ispitanih jedinjenja za obe sirovine. Dat je dateljan prikaz matematičkih modela koji se koriste za opisivanje natkritične ekstrakcije etarskih ulja i masnih ulja, počev&scaron;i od najop&scaron;tijeg modela koji uključuje diferencijalne bilanse mase za rastvorak u masi natkritičnog fluida, u fluidu unutar pora čestica usitnjenog matrijala i u čvrstoj fazi, koji se uvođenjem određenih pretpostavki pojednostavljuje i svodi na modele koji su izabrani da budu ispitani u okviru ovoga rada. Ispitani su modeli kreireni po analogiji sa hlađenjem vrele kugle u masi fluida, tj. modeli tipa jedne sfere i to: Model jedne sfere-1 (MJS-1), koji pored uticaja koeficijenta efektivne difuzije ulja u materijalu na brzinu prenosa mase uzima u obzir uticaj koeficijenta prenosa mase kroz film natkritičnog fluida oko čestice, pri čemu je njegova vrednost procenjena preko postojećih korelacija; MJS-1 (2 par), u kome je spolja&scaron;nji koeficijent prenosa mase uzet kao drugi prilagodljiv parametar modela; MJS-2, gde je koeficijent efektivne difuzije jedini prilagođeni parametar, Model karakterističnog vremena i pro&scaron;ireni model klipnog toka koji je predložila Sovov&aacute;. Za modelovanje natkritične ekstrakcije ulja semena tikve kori&scaron;ćen je i kombinovani model Honga i sar. Softverskim paketima Mathcad 2001 Professional i Solver dodatka unutar Microsoft Excel 2003, određeni su parametri ispitanih modela u cilju najboljeg slaganja modela sa ekperimentalnim podacima. Za obe ispitane sirovine, među ispitanim modelima, izabrani su modeli koji najbolje opisuju njihovu ekstrakciju natkritičnim ugljendioksidom. Pro&scaron;ireni model klipnog toka koji je predložila Sovov&aacute; pokazao se podjednako dobrim za modelovanje natkritične ekstrakcije obe sirovine i ne&scaron;to bolji od ostalih primenjenih modela.</p> / <p>This study provides results of supercritical carbon dioxide (SCCO₂) extraction of juniper berries (<em>Juniperus communis</em> L.) and pumpkin seeds (<em>Cucurbita pepo</em> L. convar.&nbsp;<em>citrullina</em>) in a laboratorysupercritical fluid extraction apparatus. The influence<br />of pressure, temperature, particle size and carbon dioxide flow on the extraction kinetics of pumpkin seed oil and juniper berry essential oil was studied. Ground pumpkin seeds were also extracted with supercritical carbon dioxide in NOVA-SWISS, High Pressure Extraction Plant, and with hexane and petroleum ether in a laboratory Soxhlet extractor. This work was also aimed to investigate the evolution of the composition of juniper fruit supercritical CO₂ extracts with time, at different extraction pressures and to emphasize the most favorable condition for the extraction of different terpene hydrocarbon groups, reporting the qualitative differences among extracts collected during successive extraction time periods. Juniper berry extracts were analyzed by capillary gas chromatography, using flame ionization (GC-FID) and mass spectrometric detection (GC-MS). More than 200 constituents were detected in the extracts and the contents of 50 compounds were reported in the work. Dependence of the percentage yields of monoterpene, sesquiterpene, oxygenated monoterpene and oxygenated sesquiterpene hydrocarbon groups on extraction time was investigated and conditions that favored the yielding of each terpene groups were emphasized. GC-MS analysis of FAME, prepared by transesterification of pumpkin seed oil with KOH in methanol, was performed. Fatty acid compositions of supercritical CO₂ pumpkin seed extract fractions collected in successive time intervals over the course of the extraction were determined. The same fractions were analyzed by high pressure liquid chromatography (HPLC), using diode-array detector (DAD) in order to determine a- and g-tocopherol contents. Sterol and squalene contents were determined by GC-MS analysis, as well. Conditions that favored the yielding of tocopherols, squalene and sterols were emphasized. A general mass transfer model and its simlifications were analysed. Extraction curves were evaluated by &ldquo;hot sphere&rdquo; mathematical models SSM-1 (Single Sphere Model 1 &ndash; in which the external mass transfer coefficient also influences the extraction profile and film mass transfer coefficients were estimated by the correlations), SSM-1 (2 par) (film mass transfer coefficient is used as the second adjustable parameter), SSM-2 (only effective diffusivity influence is considered), Characteristic time model and by the extended Lack&rsquo;s plug-flow model given by Sovov&aacute;. A combined model of Hong et al. was also fitted to the experimental data for pumpkin seed oil SCCO_2&nbsp;extractions. Relative merits of the models are demonstrated. Good agreement between the extended Lack&rsquo;s plug-flow model and the experimental measurements was obtained.</p>