<p>Zadatak ove doktorske disertacije bio je da se utvrdi tok i intenzitet lipolitičkih i oksidativnih promena u tradicionalnoj fermentisanoj kobasici (<em>Petrovačka kobasica</em>) tokom procesa razvoja tehnologije i standardizacije bezbednosti i kvaliteta ovog proizvoda, u cilju dobijanja bezbednog proizvoda, standardnog, vrhunskog kvaliteta, koji bi se kontinuirano mogao proizvoditi i plasirati, na na&scaron;e i trži&scaron;te Evropske Unije.<br />U cilju realizacije postavljenog zadatka tokom tri proizvodne sezone izrađeno je trinaest modela<em> Petrovačke kobasice</em> kako bi se ispitao uticaj vi&scaron;e varijabilnih faktora (proizvodna sezona, vreme otko&scaron;tavanja, način pripreme nadeva, vrsta omotača, su&scaron;enje i zrenje u tradicionalnim i kontrolisanim uslovima, dodatak starter kulture, način pakovanja i dužina skladi&scaron;tenja) na kvantitativne promene na lipidima, kao i na tok i intenzitet lipolitičkih i oksidativnih promena, te posledično i na profil mirisa i ukusa, kao važne karakteristike senzornog kvaliteta. Kvantitativne promene na lipidima tokom procesa proizvodnje <em>Petrovačke kobasice</em> utvrđene su određivanjem vi&scaron;e parametara, kao &scaron;to su sadržaj ukupnih lipida, masnokiselinski sastav i sadržaj ukupnog holesterola. Lipolitičke promene tokom procesa dimljenja, fermentacije, su&scaron;enja, zrenja i skladi&scaron;tenja praćene su određivanjem sadržaja slobodnih masnih kiselina, dok su oksidativne promene kvantifikovane preko sadržaja sekundarnih produkata<br />oksidacije lipida, malondialdehida i zasićenih alifatičnih aldehida. Na osnovu prikazanih rezultata može se zaključiti da u kobasicama izrađenim od ohlađenog mesa u uslovima su&scaron;enja i zrenja na nižim temperaturama (prosečna temperatura oko 10 ⁰C), koje<br />prati i sporiji pad vrednosti pH (60. dan pH&ge;5,3) dolazi do manjih lipolitičkih i oksidativnih promena na lipidima (kobasice B1 i B2 grupe). Ovaj model tradicionalne proizvodnje dovodi i do neznatnih oksidativnih promena i očuvanja poželjnih senzornih<br />svojstava mirisa i ukusa tokom dužeg vremena skladi&scaron;tenja (9 meseci od dana proizvodnje), te se može smatrati optimalnim modelom koji se mora preneti i u kontrolisane uslove proizvodnje. Takođe, zaključeno je da pakovanje u vakuumu i u modifikovanoj atmosferi, te upotreba komercijalne starter kulture, dovodi do smanjenja<br />intenziteta oksidativnih promena na lipidima, tokom skladi&scaron;tenja, odnosno celokupnog procesa proizvodnje<em> Petrovačke kobasice</em>. Dovodeći u vezu nastale produkte oksidacije<br />lipida sa senzornim profilom mirisa i ukusa može se zaključiti da vrednosti malondialdehida do 1,3 mg/kg ne utiču na značajnije naru&scaron;avanje senzornih svojstava<br />mirisa i ukusa <em>Petrovačke kobasice</em>.</p> / <p>The aim of this PhD thesis was to determine the course and intensity of the lipolytic and oxidative changes in traditional fermented sausage (Petrovac sausage) throughout the process of technology development, as well as the standardization of safety and quality of this product in order to obtain safe product of standard, superior quality, which could be continuously produced and placed on the market of our country as well as the market of European Union.</p><p>In order to realize the aim, during three seasons of production thirteen models of Petrovac sausage were produced with the aim to investigate multiple variable factors (season of production, time of deboning, filling preparation method, type of casings, drying and ripening in traditional and controled conditions, starter culture addition, packaging and storage period) on lipid quality changes, as well as on the course and intensity of lipolytic and oxidative changes and, consequently, the odor and flavor profile as important characteristics of sensory quality.</p><p>Quality changes on lipids during production of Petrovac sausage were determined using multiple parameters, such as the content of total lipids, fatty acids composition and content of total cholesterol. The lipolytic changes throughout the process of smoking, fermentation, drying, ripening and storage were monitored through the content of free fatty acids, while the oxidative changes were quantified based on the content of secondary products of lipid peroxidation, malondialdehyde and saturated aliphatic aldehydes. Based on the presented results it could be concluded that in the sausages made of cooled meat in the conditions of drying and ripening in lower temperatures (average temperature about 10 0C), which are followed by the slower drop of pH values (60. day pH &ge;5.3) comes to a lesser lipolytic and oxidative changes in lipids (sausages of B1 and B2 groups). This model of production results in<br />slight oxidative changes and the preservation of favourable sensory properties of odor and flavor during longer storage period (9 months since the date of production), so it could be considered as the optimal model, that should also be applied in the controled conditions of production.</p><p>It was also concluded that vacuum packaging and modified atmosphere packaging, as well as the usage of starter culture results in the decrease of intensity of oxidative changes on lipids throughout the entire production process of Petrovac sausage. Correlating the created products of lipid peroxidation with the sensory profile of odor and flavor, it could be concluded that the content of malondialdehyde up to 1.3<br />mg/kg has no significant effect on the deterioration of sensory properties of odor and flavor of Petrovac sausage.</p>

<p>Konditorska industrija Srbije za proizvodnju mazivog krem proizvoda isključivo koristi sojin lecitin. Veliki obim proizvodnje ulja iz semena suncokreta i uljane repice u Srbiji uticao je na proizvodnju suncokretovog i repičinog lecitina, kao nusproizvoda postupka degumiranja u fazi rafinacije ovih ulja.<br />Masna faza mazivog krem proizvoda sadrži biljne masti dobijene metodama hidrogenacije, koje kao nusprodukte imaju visok udeo nepoželjnih trans-masnih kiselina. U cilju pobolj&scaron;anja mazivosti ovog proizvoda dodaje se i rafinisano suncokretovo ulje, koje sadrži veliki udeo linolne esencijalne masne kiseline, kao i &alpha;-tokoferol (E vitamin), ima prosečan sadržaj sterola, nizak sadržaj skvalena i karotenoida, ali gotovo da ne sadrži esencijalnu &alpha;-linolensku masnu kiselinu i antioksidante &delta;- i &gamma;-tokoferol.<br />U prvoj fazi doktorske teze ispitana je mogudnost zamene sojinog lecitina u proizvodnji mazivog kakao-krem proizvoda sa suncokretovim i repičinim lecitinom u smislu optimizacije koncentracije dodatog lecitina i vremena mlevenja u laboratorijskom kugličnom mlinu. U drugoj fazi ispitana je mogudnost pobolj&scaron;anja nutritivne vrednosti mazivog kakao-krem proizvoda zamenom dela i celokupne količine suncokretovog ulja funkcionalnim uljima iz semena soje, uljane repice i susama.<br />Gasnom hromatografijom ispitan je sastav masnih kiselina u masti, biljnim uljima i lecitinima različitog porekla, gde je u lecitinima određen i sastav fosfolipida primenom kvantitativne fosforne nuklearno-magnetno-rezonantne tehnike. Kristalizacione osobine masne faze mazivog kakao-krem proizvoda ispitane su pulsnom nuklearno-magnetnom-rezonantnom spektroskopijom, dok je kinetika kristalizacije definisana primenom Gompertz-ovog matematičkog modela.<br />Reolo&scaron;ke karakteristike mazivog kakao-krem proizvoda ispitane su rotacionom viskozimetrijom, određene su teksturalne karakteristike proizvoda na teksturometru i toplotne osobine primenom diferencijalne skenirajude kalorimetrije. Boja proizvoda definisana je tristimulusnom kolorimetrijom, a senzorna analiza određena je metodom skale u vremenskom intervalu od &scaron;est meseci čuvanja uzorka na tamnom mestu i sobnoj temperaturi. Ispitivanje održivosti mazivog kakao-krem proizvoda obuhvatilo je određivanje nastalih aldehida, kao proizvoda oksidacije lipida, gasnom hromatografijom.</p> / <p>Soy lecithin is widely used emulsifier in confectionery industry of Serbia. On the other hand, there is a large production of sunflower and rapeseed oil, which contributed the production of sunflower and rapeseed lecithin as a by-product of degumming of crude oil during refining process. Another issue is a high level of undesirable trans-fatty acids in hydrogenated vegetable fats that are being used in the production of cream spread. Beside hidrogenated fats, cream product contains sunflower oil with essential fatty acids (oleic and linoleic) and &alpha;-tocopherol (E vitamin), has an average content of sterols, squalene and a low content of carotenoids, but almost does not contain the essential &alpha;-linolenic acid and antioxidants, &delta;-and &gamma;-tocopherol.<br />The first phase of this work investigates<br />the possibility of soy lecithin replacement in cocoa spread cream production with sunflower and rapeseed lecithin, in terms of optimizing the amount of lecithin and milling time in laboratory ball mill.<br />The second phase investigates nutrition value improvement of cocoa spread cream, with partly or completely replacing sunflower oil with functional soybean, rapeseed and sesame oil.<br />Gas chromatography was used in order to examine the fatty acid composition in edible non trans-fat and vegetable oils, as well as in lecithin from different sources. Phospholipid composition in soy, sunflower and rapeseed lecithin was determined using quantitative phosphorus nuclear magnetic resonance technique. Crystallization properties of fat phase of cocoa spread cream were examined by pulsed nuclear magnetic resonance spectroscopy, while crystallization kinetics was defined using the Gompertz&#39;s mathematical model.<br />Rheological properties of cocoa spread cream were analyzed by rotational viscosity, certain textural characteristics were determined using texture analyser and also thermal properties using differential scanning calorimetry. The color on the surface of cocoa spread cream was defined using tristimulus colorimetric method, and sensory analysis was determined by the scale over a period of six months of storage in the dark and room temperature. Shelf-life of cocoa spread cream was determined applying gas chromatographic analyses of the formed aldehydes as secondary products of lipid oxidation.</p>

<p>Prema najnovijim istraživanjima modifikovanim skrobovima može se pripisati jo&scaron; jedna uloga &ndash; aditivi u pekarstvu, s obzirom da utiču na pobolj&scaron;anje kvaliteta hleba i<br />usporavaju proces starenja. Međutim, prema saznanjima autora ove disertacije, ne<br />postoje istraživanja na temu uticaja emulgujućih skrobova (skrob-natrijum<br />oktenilsukcinata, OSA skrobova) na kvalitet testa i hleba od p&scaron;eničnog bra&scaron;na.<br />Uzimajući u obzir činjenicu da druge vrste modifikovanih skrobova ispoljavaju dobre<br />osobine u smislu pobolj&scaron;anja kvaliteta hleba i da je OSA skrob nutritivno vredna<br />sirovina, s obzirom da se u organiznu pona&scaron;a kao prehrambeno vlakno, od velike je<br />važnosti ispitati ulogu OSA skroba kao aditiva u pekarstvu.<br />Međutim, usled kompleksne prirode testa kao sistema, bilo je te&scaron;ko odrediti relativni<br />uticaj pojedinačnih komponenti (proteina, p&scaron;eničnog skroba, OSA skroba) i njihovih<br />međusobnih interakcija na osobine testa. Stoga je, u cilju rasvetljavanja uticaja različitih OSA skrobova na viskoelastične osobine testa i retrogradaciju skrobne komponente (fenomen povezan sa starenjem hleba), p&scaron;enično bra&scaron;no frakcionisano na gluten i skrob, i vr&scaron;ena su ispitivanja strukturnih, reolo&scaron;kih i termičkih osobina hidratisanog glutena i skrobnih gelova sa dodatkom OSA skroba. Takođe su pripremani i model sistemi testa.<br />Ispitivanja na realnim sistemima (testo i hleb) izvođena su zamenom 2,5; 5 i 10%<br />p&scaron;eničnog bra&scaron;na, jednim od tri vrste OSA skroba: skrob-natrijum oktenilsukcinatom<br />(OSA-ST), preželatiniziranim skrob-natrijum oktenilsukcinatom (Pregel OSA-ST) i<br />hidrolizovanim su&scaron;enim u spreju skrob-natrijum oktenilsukcinatom (Hydrol OSA-ST).<br />Cilj je bio da se ispita uticaj dodatka OSA skrobova na strukturu testa (SEM), empirijske (miksolab, alveograf i reofermentometar) i fundamentalne (oscilatorna merenja i testovi puzanja i deformacije) reolo&scaron;ke osobine, kao i parametre kvaliteta hleba (specifična zapremina, boja kore i sredine hleba, vlaga sredine hleba, parametri raspodele veličine pora i tekstura sredine). Pored pomenutog, praćena je i promena kvaliteta hleba tokom skladi&scaron;tenja, kako bi se dobio uvid u kinetiku starenja hleba.<br />Rezultati dobijeni u ovoj disertaciji ukazali su da reolo&scaron;ko pona&scaron;anje testa sa dodatkom OSA skrobova zavisi od strukture skrobnih granula, tj. od stepena dezintegracije i depolimerizacije granule tokom procesa modifikacije. Stoga je dodatak OSA-ST doveo do ojačavanja glutenske mreže &scaron;to se odrazilo na porast modula elastičnosti i testa i glutena. Nasuprot tome, Pregel and Hydrol OSA-ST uticali su na kontinualnost glutenske mreže koja je u njihovom prisustvu bila poroznija, a time su i dobijena testa bila mek&scaron;a i rastegljivija. Istraživanja na realnim i model sistemima (p&scaron;enični skrob sa dodatkom OSA skroba) ukazala su da sva tri OSA skroba usporavaju retrogradaciju p&scaron;eničnog skroba. Takođe je dokazano da svi ispitivani emulgujući skrobovi povećavaju specifičnu zapreminu hleba u poređenju sa kontrolnim, pri čemu je Pregel OSA ispoljio najjači efekat. To se odrazilo i na strukturne osobine sredine hleba, a posledično i na mehaničke osobine sredine, čija promena je praćena u cilju određivanja kinetike starenja hleba. Prema dobijenim rezultatima, vrednosti čvrstoće sredine hleba koji je sadržao OSA-ST i Pregel OSA-ST su i nakon 24 h bile slične ili značajno niže od vrednosti čvrstoće kontrolnog uzorka određene 2 h nakon pečenja.</p> / <p>Recent studies have demonstrated that modified starches can be used as novel additives in breadmaking since they improve bread quality and retard stalling. However, up to the author&#39;s knowledge, there are no investigations concerning the influence of emulsifying starches (starch sodium octenyl succinates - OSA starches) on wheat flour dough and bread quality. Taking into account the fact that other modified starches have exhibited significant bread improving properties and that OSA starch has special nutritional value since it can act as functional fibre, it is of a great importance to investigate the feasibility of OSA starch as bread improver.<br />However, due to the complex nature of dough, it was difficult to determine the relative contributions of protein, native and modified starch components and their interactions on dough properties. Therefore, in order to resolve the influence of different OSA starches on dough viscoelastic properties and starch retrogradation (the phenomenon related to bread stalling), wheat flour was fractionated into gluten and starch; and the structural, rheological and thermal behaviour of the hydrated gluten samples and starch gels supplemented with emulsifying starches was also studied. Dough model systems were also prepared.<br />Experiments on real systems (dough and bread) were performed by incorporating<br />starch sodium octenyl succinate (OSA-ST), pregelatinized OSA starch (Pregel OSA-ST) and hydrolysed spray-dried OSA starch (Hydrol OSA-ST) at 2.5, 5 and 10 % into wheat flour. The aim was to investigate the effect of incorporating OSA starches on dough structural (SEM imaging), empirical (Mixolab, Alveograph, Rheofermentometre) and fundamental (oscillatory and creep measurements) rheological properties as well as bread quality parameters (specific loaf volume, crust and crumb colour, crumb moisture, crumb grain features, crumb texture). In addition, the bread quality attributes during storage were also monitored in order to get insight into bread stalling kinetics.<br />The results obtained in this thesis revealed that the rheological behaviour of OSA starch supplemented dough depended on the OSA starch granule rigidity, i.e. extent of OSA starch granule disintegration and polysaccharide degradation during modification. OSA-ST starch caused a reinforcement of the gluten network, as shown by the increase in storage modulus of doughs and gluten. On contrary, Pregel and Hydrol OSA-ST affected the continuity of gluten network which became porous and thus produced softer and stickier doughs in comparison to control. Investigations on real dough and model systems containing wheat and OSA starches revealed that all three types of OSA starches reduced starch retrogradation.<br />In general, all the examined emulsifying starches increased bread loaf volume in comparison to control bread with no added polymers, while Pregel OSA starch has expressed the greatest impact. It also reflected on bread crumb structural features and consequently on the crumb mechanical properties which were used for bread stalling monitoring. Firmness values of OSA-ST and Pregel OSA-ST starch supplemented bread crumbs, after 24 h of storage, were similar to or significantly lower than those of control determined 2 h after baking.</p>

<p>У овој докторској дисертацији, комбуха је<br />култивисана на екстрактима ртањског чаја,<br />нане, коприве и мајчине душице заслађеним<br />са 7% сахарозе. Напици од комбухе добијени<br />на наведеним екстрактима су даље<br />коришћени као инокулуми за ферментацију<br />млека са 0,8; 1,6 и 2,8% млечне масти, на<br />температурама од 37, 40 и 43&deg;С.<br />Истраживање је обухватило праћење<br />антиоксидативне активности различитих<br />ферментисаних млечних производа<br />добијених помоћу комбухе, и то<br />утврђивањем способности везивања<br />слободних радикала, како веома реактивних<br />хидрокси-радикала, тако и мање реактивних,<br />стабилних 1,1-дифенил-2-пикрилхидразил<br />(DPPH) радикала. Урађена је<br />карактеризација млека, инокулума и<br />добијених производа утврђивањем физичко-<br />хемијских карактеристика, а у случају<br />производа и сензорном оценом. За млеко и<br />производе је измерен и садржај масних<br />киселина. Осим тога, одређени су и неки од<br />састојака производа за које се зна да имају<br />антиоксидативно деловање, при чему је<br />акценат стављен на витамин Це, као и<br />полинезасићене масне киселине.<br />Оптимизацијом температуре ферментације,<br />садржаја млечне масти полазног млека,<br />врсте инокулума комбухе, као и релевантних<br />састојака производа, утврђени су оптимални<br />услови за добијање најквалитетнијег<br />ферментисаног млечног производа од<br />комбухе са аспекта антиоксидативне<br />активности.</p> / <p>U ovoj doktorskoj disertaciji, kombuha je<br />kultivisana na ekstraktima rtanjskog čaja,<br />nane, koprive i majčine dušice zaslađenim<br />sa 7% saharoze. Napici od kombuhe dobijeni<br />na navedenim ekstraktima su dalje<br />korišćeni kao inokulumi za fermentaciju<br />mleka sa 0,8; 1,6 i 2,8% mlečne masti, na<br />temperaturama od 37, 40 i 43&deg;S.<br />Istraživanje je obuhvatilo praćenje<br />antioksidativne aktivnosti različitih<br />fermentisanih mlečnih proizvoda<br />dobijenih pomoću kombuhe, i to<br />utvrđivanjem sposobnosti vezivanja<br />slobodnih radikala, kako veoma reaktivnih<br />hidroksi-radikala, tako i manje reaktivnih,<br />stabilnih 1,1-difenil-2-pikrilhidrazil<br />(DPPH) radikala. Urađena je<br />karakterizacija mleka, inokuluma i<br />dobijenih proizvoda utvrđivanjem fizičko-<br />hemijskih karakteristika, a u slučaju<br />proizvoda i senzornom ocenom. Za mleko i<br />proizvode je izmeren i sadržaj masnih<br />kiselina. Osim toga, određeni su i neki od<br />sastojaka proizvoda za koje se zna da imaju<br />antioksidativno delovanje, pri čemu je<br />akcenat stavljen na vitamin Ce, kao i<br />polinezasićene masne kiseline.<br />Optimizacijom temperature fermentacije,<br />sadržaja mlečne masti polaznog mleka,<br />vrste inokuluma kombuhe, kao i relevantnih<br />sastojaka proizvoda, utvrđeni su optimalni<br />uslovi za dobijanje najkvalitetnijeg<br />fermentisanog mlečnog proizvoda od<br />kombuhe sa aspekta antioksidativne<br />aktivnosti.</p> / <p>In this PhD thesis, kombucha was cultivated on winter savory, peppermint, stinging nettle and wild thyme tea extracts, sweetened with 7% of sucrose. The kombucha beverages obtained on these extracts were used as inoculums for the fermentation of milk with 0.8; 1.6 and 2.8% milk fat, at temepratures of 37, 40 and 43&deg;С.<br />The investigation determined the antioxidant activity of different fermented milk products obtained by kombucha. The ability of free radicals (DPPH and hydroxyl) scavenging was established. The physicochemical characteristics of milk, inoculums and the obtained products were measured. The sensory analysis of the products was also performed. The content of fatty acids in milk and products was determined. The content of some of the product components with the antioxidant characteristics<br />(vitamin C and polyunsaturated fatty acids) was measured. Optimization of process temperature, milk fat content, type of kombucha inoculum, and relevant product components enabled the determination of optimum conditions for the obtaining of kombucha fermented milk products with the best quality, when the antioxidant activity is considered.</p>

<p>U ovom radu pripremljeni su različiti polimerni i keramički nanostrukturni materijali, u cilju ispitivanja uticaja vrste i udela nanopunila (čađ, fuleren, silicijum(IV)oksid, aluminijum(III)oksid i titanijum(IV)oksid) na strukturu, reolo&scaron;ko i toplotno pona&scaron;anje kompozita, dobijenih na osnovu stirena, metilmetakrilata i akrilamida, primenom različitih metoda sinteze. Ispitivan je uticaj prisustva različitog udela nanočestica (1, 3 i 5 %<em> m/m</em>) na kinetiku polimerizacije stirena, i na oblast prelaska u staklasto stanje polistirenskih hibridnih materijala. Sintetisana je i serija nanokompozita polimerizacijom metilmetakrilata u prisustvu čestica (silicijum(IV)oksid, aluminijum (III)oksid i titanijum(IV)oksid) različitih dimenzija i hidrofilnosti, ali istog zapreminskog udela (1 %<em> v/v</em>). Na osnovu primene izotermne diferencijalno skanirajude metode (DSC), razvijen je kinetički model za opisivanje dve razičite reakcije tokom polimerizacije vinilnih monomera (reakciju prvog reda i samoubrzanje), i izračunata je debljina međufaznog sloja polimera na čestici u cilju određivanja njegovog uticaja na temperaturu prelaska u staklasto stanje hibridnih materijala. Za ispitivanje strukture i morfologije polistiren/silicijum(IV)oksid nanokompozita dobijenih metodom isparavanja rastvarača, kori&scaron;dene su infracrvena spektroskopija sa Furijeovom transformacijom (FT-IR) i skanirajuda elektronska mikroskopija (SEM). Radi utvrđivanja uticaja udela hidrofobnog silicijum(IV)oksida (2, 5, 10, 15 i 30 %<em> m/m</em>) na toplotnu postojanost polistirenskih materijala, primenjene su istovremena termogravimetrijska i diferencijalno skanirajuda analiza (TG-DSC). Takođe, određen je uticaj veličine čestice fulerena C60 i submikronske čestice čađi na reolo&scaron;ka svojstva polistirenskih kompozita sintetisanih taloženjem polimera iz rastvora. Ispitivanjem reolo&scaron;kog pona&scaron;anja hibridnih materijala, proučavan je uticaj veličine čestica, molekulske mase polimera i indeksa polidisperznosti na viskoznost polistirenskih kompozita. Na osnovu<em> in-situ</em> reolo&scaron;kih analiza polimerizacije u toku želiranja suspenzije nanočestica aluminijum(III)oksida u vodenom rastvoru monomera metakrilamida i N,N&rsquo;-metilenbisakrilamida, utvrđena je jaka katalitička aktivnost povr&scaron;ine aluminijum(III)oksida na nastajanje slobodnih radikala. Radi nalaženja veze između željenih svojstava keramičkih proizvoda i načina njihovog dobijanja, proučavan je uticaj uslova vođenja polimerizacije na slaganje čestica u dobijenom odlivku i na gustinu krajnjeg sinterovanog proizvoda.</p> / <p>In this work, polymeric and ceramic nanostructured materials were prepared using different methods, in order to investigate the influence of nanofiller content and its type (carbon black, fullerene, silica, alumina and titania) on the structure, rheological and thermal behavior of composites, based on styrene, methylmethacrylate and acrylamide. The effect of particles content (1, 3 and 5 wt. %) on the kinetics of styrene radical polymerization and on the glass transition temperature of polystyrene/silica composites was investigated. A series of polymethylmethacrylate nanocomposites containing 1 vol. % of silica, alumina or titania particles (differing in dimensions and surface properties) was obtained. On the basis of isothermal differential scanning calorimetry (DSC), the kinetic model for describing two reactions during vinyl monomer polymerization (first order and autoacceleration) was developed, and the thickness of interfacial layer formed on nanoparticle surface was determined, in order to investigate its influence on the glass transition temperature of polymethylmethacrylate hybrid materials. The structure and the morphology of polystyrene/silica nanocomposites prepared by solvent evaporation were investigated using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The influence of&nbsp; hydrophobic silica content (2, 5, 10, 15 and 30 wt. %) on polystyrene thermal stability was studied by simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC). The effect of fullerene C60 and submicron carbon black particle size on rheological properties of polystyrene composites prepared by the rapid coprecipitation was determined. Following the rheology of hybrid melts, the influence of filler size, molecular weight and polydispersity of polymer matrix on the viscosity of polystyrene composites was studied. On the basis of in-situ rheology analysis of polymerization process during the gelation of alumina nanoparticles suspension in aqueous solution of methacrylamide and N,N&rsquo;- methylene bisacrylamide monomers, the strong catalytic activity of alumina surface on the free radicals formation was determined. In order to find the correlation between desired properties of ceramic products and their preparation procedure route, the influence of polymerization conditions on the green body structure and sintered body density was studied in details.</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>Suncokretova sačma ima manju zastupljenost u peletiranim sme&scaron;ama za<br />ishranu životinja od sojine sačme zbog većeg udela sirovih vlakana. Sirova<br />vlakna depresivno deluju na svarljivost obroka i proizvodne rezultate, a mogu<br />da imaju negativan uticaj na fizički kvalitet peleta. Pri peletiranju sme&scaron;a za<br />ishranu životinja u poslednje vreme značajna pažnja se posvećuje<br />funkcionalnim promenama makronutrijenata, jer se smatra da ove promene<br />pozitivno utiču na fizički kvalitet peleta. Razvojem modernih analitičkih tehnika,<br />posebno termalne analize, moguće je opisati promene na skrobu u procesu<br />peletiranja, nastale usled uticaja toplote i vlage. Sa druge strane, promene na<br />proteinskoj komponenti u procesu peletiranja nisu dovoljno obja&scaron;njene.<br />Najče&scaron;će se tumačenja svode na pretpostavke, bez obja&scaron;njenja o promenama<br />u veličini molekula proteina, kao i njihovoj koncentraciji. Inovativan pristup ove<br />doktorske disertacije je usmeren na opisivanje uticaja dodatka sojine i<br />suncokretovih sačmi različitog sadržaja proteina u sme&scaron;e na bazi kukuruza na<br />tehnolo&scaron;ke parametre procesa peletiranja, funkcionalne promene<br />makronutrijenata (želatinizaciju skroba i denaturaciju i degradaciju proteina) i<br />fizički kvalitet peleta. U okviru svake sme&scaron;e takođe je ispitivan uticaj procesnih<br />parametara, prečnika otvora sita mlina čekićara (2, 3 i 4 mm), vremena<br />produženog kondicioniranja parom (bez produženog kondicioniranja, 5 i 10<br />minuta) na fizički kvalitet peleta. Istraživanja su pokazala da temperatura<br />peletiranja, specifična potro&scaron;nja električne energije i udeo pra&scaron;ine u peletama<br />zavise od sirovinskog sastava sme&scaron;a, prečnika otvora sita mlina čekićara i<br />vremena zadržavanja u kondicioneru, pri čemu temperatura peletiranja i<br />specifična potro&scaron;nja električne energije rastu, a udeo pra&scaron;ine u peletama<br />opada sa porastom koncentracije proteina u sme&scaron;ama. Dokazano je i da<br />proces peletiranja utiče na funkcionalne promene makronutrijenata,<br />želatinizaciju skroba i strukturne promene na proteinima. Takođe je dokazano i<br />da za optimalno vreme zadržavanja materijala u kondicioneru, smanjenje<br />prečnika otvora sita mlina čekićara i povećanje sadržaja proteina u sme&scaron;ama<br />utiču na pobolj&scaron;anje fizičkog kvaliteta peleta, tj. tvrdoće peleta i stepena<br />otiranja peleta. Optimalni uslovi procesa peletiranja određeni su metodom<br />željene funkcije. Dat je predlog opsega procesnih parametara za dobijanje<br />peleta minimalnog stepena otiranja uz optimalnu specifičnu potro&scaron;nju<br />električne energije.<br />Istraživanja u ovoj doktorskoj disartaciji dala su doprinos novim saznanjima o<br />uticaju dodatka sačme različitog sadržaja proteina (37,3, 40,3 i 42,6 %) na<br />fizički kvalitet peleta. Kvalitet peleta sa dodatkom suncokretove sačme je<br />poređen sa kvalitetom peleta sa dodatom sojinom sačmom, kao i kvalitetom<br />peleta od čistog kukuruza, u cilju obja&scaron;njenja uticaja izvora i koncentracije<br />proteina. Ispitivanja su vr&scaron;ena ne samo za standardno vreme kondicioniranja,<br />nego uz primenu najsavremenijih postupaka termičke obrade hrane za<br />životinje, tj. uz upotrebu produženog kondicioniranja od 5 i 10 minuta.<br />Doprinos nauci je dat i time &scaron;to je pokazano da proces peletiranja utiče ne<br />samo na denaturaciju i degradaciju proteina, nego i na njihovo povezivanje.</p> / <p>Sunflower meal has a lesser presence in pelleted compound feed than<br />soybean meal due to a higher proportion of raw fiber. Raw fiber has<br />depressing effect on the digestibility and production results, and can have a<br />negative impact on the physical quality of the pellets. Lately, considerable<br />attention is paid to the functional changes of macronutrients in pelleting of<br />animal feed. It is believed that these changes have a positive impact on the<br />physical quality of the pellets. With the development of modern analytical<br />techniques, especially the thermal analysis, it is possible to describe the<br />changes of starch in pelleting process, caused by the impact of heat and<br />moisture. On the other hand, changes of the protein components in the<br />pelleting process are not sufficiently explained. The most common<br />interpretation is reduced to the presumption, with no explanation of changes in<br />the size of protein molecules, as well as in their concentration. The innovative<br />approach of this dissertation is focused on describing the effect of the addition<br />of soybean meal and sunflower meals, with different protein content, in<br />mixtures based on corn, on the technological parameters of the pelleting<br />process, functional changes of macronutrients (starch gelatinization, and<br />protein denaturation and degradation), and physical quality of the pellets.<br />Within each of the mixtures, the influence of process parameters, the diameter<br />of the hammer mill sieve openings (2, 3 and 4 mm), duration of long term<br />steam conditioning (without extended conditioning, 5 and 10 minutes) on the<br />physical quality of the pellets was also investigated. Studies have shown that<br />pelleting temperatures, the specific power consumption and the proportion of<br />dust in pellets were dependent of composition of the mixtures, the diameter of<br />the hammer mill sieve openings, and residence time in the conditioner.<br />Pelleting temperature and specific power consumption increased, and the<br />extent of fines in pellets decreased with increasing of concentration of protein<br />in the diets. Additionally, it is proved that pelleting process affects functional<br />changes of macronutrients, starch gelatinization and structural changes in<br />proteins. It is also proved that for the optimal retention time of material in<br />conditioner, decrease of diameter of the hammer mill sieve openings and<br />increase of protein content in the diets had positive effect on the physical<br />quality of pellets, i.e. pellet hardness and degree of abrasion of pellets. The<br />optimum process conditions in pelleting process were determined by the<br />method of desired function. A proposal has been made for setting the range of<br />process parameters for obtaining the minimum degree of abrasion of pellets,<br />with optimal specific energy consumption.<br />The research within this Ph.D. thesis contributed to the knowledge about the<br />effects of addition of sunflower meal with different protein content (37.3, 40.3<br />and 42.6 %) on the physical quality of the pellets. Quality of pelleted mixtures<br />with sunflower meal added were compared with the quality of pelleted mixtures<br />with soybean meal added and quality of pelleted corn, in order to explain the<br />effects of starch concentration, protein concentration and protein source.<br />Studies were performed not only for the standard time of conditioning, but with<br />the use of modern techniques for heat treatment of animal feed, i.e. with the<br />use of long term conditioning process for a 5 or 10 minutes. Additional<br />contribution to science has been given with showing that the pelleting process<br />causing not only the denaturation and degradation of proteins, but also<br />synthesis of proteins.</p>

<p>Upotrebom 50% etanola i superkritičnog ugljendioksida kao ekstragensa izvr&scaron;ena je ekstrakcija različitih vrsta pečuraka. Nakon određivanja prinosa suvih ekstrakata, u njima su određeni: sadržaj ukupnih fenola i ukupnih flavonoida, sadržaj makro- i mikro-elemenata, sadržaj adenozina, kao i sadržaj karakterističnih komponenata pistilarina i variegetične kiseline. Najveći sadržaj ukupnih fenolnih jedinjenja određen je u suvom ekstraktu pečurke <em>C. pistillaris</em>, najveći sadržaj ukupnih flavonoida u ekstraktu <em>D. confragosa</em>, a najvi&scaron;e esencijalnog cinka i selena sadrži suvi ekstrakt pečurke <em>B. edulis</em>. U odnosu na ostale suve ekstrakte ekstrakt pečurke <em>L. saccatum</em> sadrži nekoliko puta veću količinu adenozina. Antioksidativno delovanje suvih ekstrakata analizirano je primenom spektrofotometrijskih i EPR metode. Ekstrakti <em>C. pistillaris, B. edulis </em>i <em>A. mellea</em> pokazali su se kao najefikasniji skevindžeri najopasnije slobodnoradikalske vrste hidroksil radikala, dok se efikasnim u prevenciji lipidne peroksidacije mogu smatrati ekstrakti <em>B. edulis, A. mellea </em>i<em> L. saccatum</em>. Nakon određivanja prinosa supekritičnih ekstrakata ispitivanih pečuraka, u njima je analiziran sastav masnih kiselina i detektovana jedinjenja sterolnog tipa. U ispitivanim ekstraktima dominantna je nezasićena linoleinska kiselina, a značajan je udeo i oleinske nezasićene masne kiseline. Dominantno jedinjenje sterolne strukture u gotovo svim ekstraktima je ergosterol. Ispitan je uticaj superkritičnih ekstrakata pečuraka na fluidnost membrane eritrocita i na osnovu dobijenih rezultata zaključeno da bi značajnu ulogu u antihipertenzivnoj ishrani mogle imati pečurke <em>A. mellea </em>i<em> M. procera</em>.</p> / <p>Using 50% ethanol and supercritical carbon dioxide different mushroom extracts were prepared. After analysis of extraction yield, content of total phenols and total flavonoids, content of macro-elements and micro-elements, as well as content of adenosine and characteristic compounds (pistilarin and variegatic acid) were determined. Highest content od total phenols was determined in <em>C. pistillaris</em> extract, highest content of total flavonoids in<em> D. confragosa</em> and highest content of essential zinc and selenium in B. edulis dry extract. In comparsion to other extracts <em>L. saccatum</em> posses few time higher content of adenosine. Antioxidat activity was analysed by spectrophotometric and EPR methods. Extracts of <em>C. pistillaris</em>,<em> B. edulis</em> and <em>A. mellea</em> have been showed as a most efficient in scavenging of dangerous OH˙ radical. In lipid peroxidation prevention significant were mushrooms extracts of<em> B. edulis</em>, <em>A. mellea</em> and<em> L. saccatum</em>.<br />After determination of mushrooms supercritical extraction yield, fatty acid composition and sterol components were analysed. Dominant unsaturated fatty acid in investigated mushroom extracts was linoleic acid. Content of oleic fatty acid was also significant. Dominant compound of sterol structure, in almost all supercritical extracts, was ergosterole. Influence of supercritical mushroom extracts on eritrocite membrane fluidity was investigated. Acording to obtained results, mushrooms <em>A. mellea</em> and <em>M. procera</em> could have significant role in antihypertensive diet.</p>

No description available.

<p>U ovom radu su ispitani hemijski sastav, antioksidativna, antihiperglikemijska, antiproliferativna i antimikrobna aktivnost liofiliziranih metanolnih ekstrakata tropa<br />maline (Rubusidaeus L) sorti Meeker (ETMM) i Willamette (ETMW), kupine (RubusfruticosusL) sorti Čačanska bestrna (ETKČ) i Thornfree (ETKT) i divlje borovnice<br />(Vacciniummyrtillus L) (ETB). Sadržaj ukupnih polifenola (TPh), flavonoida (TF) i antocijana (TAc) u ekstraktima tropova određeni su spektrofotometrijskim metodama.<br />Identifikacija i kvantifikacija fenolnih jedinjenja (fenolnihkiselina, flavonola i cijanidina) i vitamina C u ekstraktima tropova izvedena je HPLC analizom. Spektrofotometrijskim<br />testovima određena je antioksidativna aktivnostna DPPH i ABTS+ radikale i redukciona sposobnost ekstrakata. ESR spektroskopijom utvrđen je uticaj ekstrakata na reaktivne hidroksil i superoksid anjon radikale. Antihiperglikemijska aktivnost ekstrakata određena<br />je testom inhibicije &alpha;-glukozidaze. Antiproliferativna aktivnost ekstrakata tropova ispitana je in vitro, njihovim delovanjem na rast četiri histolo&scaron;ki različite humane ćelije:<br />HeLa (epitelni karcinom cerviksa), MCF7 (adenokarcinom dojke), HT-29 (adenokarcinom debelog creva) i MRC-5 (humani fetalni fibroblasti pluća). Antimikrobna aktivnost ekstrakata tropova bobičastog voća ispitana je na odabrane sojeve Gram-pozitivnih i Gram-negativnih bakterija, kvasaca i plesni disk difuzionom metodom i metodom &bdquo;bunarčića&rdquo;. Ispitana je i mogućnost primene liofiliziranih ekstrakata tropova bobičastog voća kao funkcionalnog dodatka sokovima od voća. Laboratorijski proizvedenim obogaćenim sokovima je određen sadržaj TPh, TF i TAc i utvrđena antioksidativna aktivnost testom redukcione sposobnosti i DPPH testom. Rezultati ispitivanja hemijskog sastava, antioksidativne, antihiperglikemijske, antiproliferativne i antimikrobne aktivnosti ETMM, ETMW, ETKČ, ETKT i ETB ukazuju da su svi ispitivani ekstrakti tropova potencijalni izvor prirodnih<br />bioaktivnih jedinjenja, a antioksidativna aktivnost obogaćenih sokova ukazuje na mogućnost kori&scaron;ćenja ovih ekstrakata, kao funkcionalnih aditiva u proizvodnji različitih<br />visoko vrednih prehrambenih proizvoda.</p> / <p>This work examined the chemical composition, the antioxidant,<br />antihyperglycaemic, antiproliferative and antimicrobial<br />activity of the freeze-dried raspberry (Rubus idaeus L.)<br />varieties Meeker (ETMM) and Willamette (ETMW), blackberry<br />(Rubus fruticosus L.) varieties (ETKČ) and Thornfree<br />(ETKT), and wild blueberry (Vaccinium myrtillus L.) (ETB)<br />pomaces methanol extracts. The content of total polyphenols<br />(TPh), total flavonoids (TF) and total anthocyanins (TAc) in<br />the pomace extracts were determined spectrophotometrically.<br />Identification and quantification of the phenolic compounds<br />(phenol acids, flavonols and cyanidins) and ascorbic acid in<br />the pomace extracts was performed by HPLC analysis. The<br />antioxidant activities of the extracts was determined spectrophotometrically<br />using DPPH and ABTS+ free radicals and<br />reducing ability assay. ESR spectroscopy is used for determination<br />of pomace extracts&rsquo; influence on reactive hydroxyl<br />and superoxide anion radicals. Antihyperglycaemic activity of<br />the pomace extracts was determined using &alpha;-glucosidase inhibition<br />assay. The antiproliferative activity of the pomace extracts<br />was tested in vitro, testing their influence on the growth<br />of four histologically different human tumor cells: HeLa<br />(cervix epithelioid carcinoma), MCF7 (breast adenocarcinoma),<br />HT-29 (colon adenocarcinoma) and MRC-5(human fetal<br />lung fibroblasts). Antimicrobial activity of berry pomace extracts was tested on selected strains of Gram-positive and<br />Gram-negative bacteria, yeasts and molds with the disc diffusion<br />method and the method of &ldquo;wells&rdquo;. The possibility of<br />freeze dried berry pomace extracts application as a fruit functional<br />additive was investigated as well. Laboratory produced<br />enriched juice was tested in terms of TPH, TF and TAc content,<br />reducing ability and DPPH scavenging ability as well.<br />The results of testing the chemical composition, the antioxidative,<br />antihyperglycaemic, antiproliferative and antimicrobial<br />activities of ETMM, ETMW, ETKČ, ETKT and ETB, indicate<br />that all investigated pomace extracts are a potential source of<br />natural bioactive compounds, and that the antioxidant activity<br />enriched juice indicates the possibility of using these extracts,<br />as a functional additive in the production of various high-value<br />food products.</p>