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The influence of different hydroxides, applied to activate carbon black, on the electrochemical properties of activated carbon was investigated. The carbon material was prepared by hydrothermal treatment of sucrose and afterwards thermally activated using KOH, NaOH and LiOH. The electrochemical properties of the obtained samples were examined by cyclic voltammetry and electrochemical impedance spectroscopy and correlated to their physicochemical properties. All samples showed characteristic capacitor-like behaviour. The highest specific capacitance was obtained for the KOH-treated sample, while the increase in capacitance follows the sequence of the growth of ionic radius of a metal from an alkali which is used for activation. It was found that the dependence on the type of hydroxide is due to differences in the radii of a metal. The alkalies of larger radii of metal generated make pores wider and consequently the structure of a porous layer become more accessible to the charge transfer of capacitive response. Испитиван је утицај различитих активирајућих хидроксида на електрохемијска својства активираних угљеничних материјала. Угљенични материјал је добијен хидротермалним третманом сахарозе, а потом активиран помоћу KOH, NaOH и LiOH. Електрохемијска својства добијених узорака испитивана су цикличном волтаметријом и спектроскопијом електрохемијске импеданције. Синтетизовани материјали показују капацитивна својства. Највећа специфична капацитивност добијена је за узорак третиран помоћу KOH, док капацитивност прати величину пречника јона метала из алкалије којом је активиран угљенични материјал.

In the protein purification, drug delivery, food industry, and biotechnological applications involving protein−polyelectrolyte complexation, proper selection of co-solutes and solution conditions plays a crucial role. The onset of (bio)macromolecular complexation occurs even on the so-called “wrong side” of the protein isoionic point where both the protein and the polyelectrolyte are net like-charged. To gain mechanistic insights into the modulatory role of salts (NaCl, NaBr, and NaI) and sugars (sucrose and sucralose) in protein−polyelectrolyte complexation under such conditions, interaction between bovine serum albumin (BSA) and sodium polystyrene sulfonate (NaPSS) at pH = 8.0 was studied by a combination of isothermal titration calorimetry, fluorescence spectroscopy, circular dichroism, and thermodynamic modeling. The BSA−NaPSS complexation proceeds by two binding processes (first, formation of intrapolymer complexes and then formation of interpolymer complexes), both driven by favorable electrostatic interactions between the negatively charged sulfonic groups (−SO$_3^−$) of NaPSS and positively charged patches on the BSA surface. Two such positive patches were identified, each responsible for one of the two binding processes. The presence of salts screened both short-range attractive and long-range repulsive electrostatic interactions between both macromolecules, resulting in a nonmonotonic dependence of the binding affinity on the total ionic strength for both binding processes. In addition, distinct anion-specific effects were observed (NaCl < NaBr < NaI). The effect of sugars was less pronounced: sucrose had no effect on the complexation, but its chlorinated analogue, sucralose, promoted it slightly due to the screening of long-range repulsive electrostatic interactions between BSA and NaPSS. Although short-range non-electrostatic interactions are frequently mentioned in the literature in relation to BSA or NaPSS, we found that the main driving force of complexation on the “wrong side” are electrostatic interactions.

The action of three types of co-solutes: (i) salts (NaCl, NaBr, NaI), (ii) polymer (polyethylene glycol; PEG-400, PEG-3000, PEG-20000), and (iii) sugars (sucrose, sucralose) on the complexation between bovine serum albumin (BSA) and sodium polystyrene sulfonate (NaPSS) was studied. Three critical pH parameters were extracted from the pH dependence of the solution’s turbidity: pHc corresponding to the formation of the soluble complexes, pHΦ corresponding to the formation of the insoluble complexes, and pHopt corresponding to the charge neutralization of the complexes. In the presence of salts, the formation of soluble and insoluble complexes as well as the charge neutralization of complexes was hindered, which is a consequence of the electrostatic screening of attractive interactions between BSA and NaPSS. Distinct anion-specific trends were observed in which the stabilizing effect of the salt increased in the order: NaCl < NaBr < NaI. The presence of PEG, regardless of its molecular weight, showed no measurable effect on the formation of soluble complexes. PEG-400 and PEG-3000 showed no effect on the formation of insoluble complexes, but PEG-20000 in high concentrations promoted their formation due to the molecular crowding effect. The presence of sugar molecules had little effect on BSA-NaPSS complexation. Sucralose showed a minor stabilizing effect with respect to the onset of complex formation, which was due to its propensity to the protein surface. This was confirmed by the fluorescence quenching assay (Stern-Volmer relationship) and all-atom MD simulations. This study highlights that when evaluating the modulatory effect of co-solutes on protein-polyelectrolyte interactions, (co-solute)-protein interactions and their subsequent impact on protein aggregation must also be considered.

U proizvodnji ploča iverica kao glavna sirovina za ljepilo koriste se produkti petrokemijske industrije. Iako se takvim ljepilima postižu iznimna fizikalna i mehanička svojstva ploča iverica, u današnje vrijeme ta sirovina ne zadovoljava ekološke standarde, stoga se nastoje pronaći adekvatna zamjenska sirovina koja bi zadovoljila i ekološke standarde ali i mehaničke i fizikalne prohtjeve. Kao jedno od rješenja nameću se ploče iverice izrađene adhezivom na bazi limunske kiseline i saharoze. Budući da je ta sirovina još u fazi istraživanja i u literaturi postoji relativno mali broj podataka koji govore o mogućnosti uporabe te sirovine kao adekvatne zamjene klasičnim ljepilima, u sklopu ovog završnog rada izradile su se i ispitale (fizikalna i mehanička svojstva) eksperimentalne ploče iverice izrađene uporabom adheziva na bazi limunske kiseline i saharoze. Uzorci izrađenih ploča ispitivani su u skladu s odrednicama HRN EN normi. Rezultati istraživanja pokazali su da svojstva ploča uvelike ovise o dimenzijama osnovne sirovine (drvnog iverja), koja diktira i proizvedenu gustoću ploča a o čemu izravno ovise i mehanička svojstva ploča. Ipak, rezultati ispitivanja sugeriraju da je primjena ovakve vrste adheziva potencijalno jako dobro industrijsko rješenje za zamjenu smola na formaldehidnoj osnovi.

Zbog sve češćih pojava alergija na kravlje mlijeko i netolerancije na laktozu, te veće brige potrošača za zdravlje, okoliš i dobrobit životinja, suvremeni čovjek se okreće ka upotrebi biljnih napitaka i proizvoda na biljnoj bazi. U ovom radu je optimirana fermentacija kokosovog napitka uz dodatke s ciljem dobivanja fermentiranog kokosovog deserta. Praćen je tijek fermentacije i određivana su fizikalno – kemijska, senzorska i reološka svojstva dobivenih kokosovih deserata. Fermentiran je kokosov napitak (kontrola) te kokosov napitak uz dodatak brašna sjemenki rogača sa ili bez dodatka stevije ili saharoze. Vrijeme fermentacije kokosovog napitka iznosilo je 14 h. Fermentirani napitci promatrani su kroz period od 14 dana. Svim fermentiranim uzorcima pratio se udjel soli, mineralnih tvari i suhe tvari, te određivali kiselost, kapacitet odvajanje vode, sinereza, reološki parametri te mikrobiološka i senzorska analiza. Senzorski najbolje ocjenjen napitak je fermentirani kokosov napitak s dodatkom brašna sjemenki rogača s 3 % saharoze.

Namen diplomske naloge je bil s pomočjo diferenčne dinamične kalorimetrije poiskati razlike med termično obremenitvijo mešanic asparagin/glukoza, asparagin/fruktoza in asparagin/saharoza ter skupaj s pregledom literature ugotoviti in pojasniti povezavo med vrsto sladkorja in nastankom akrilamida med toplotno obdelavo živil. Omenjene mešanice in posamezne komponente smo z enakomerno hitrostjo segrevali do 130 °C. V drugem delu poskusa smo iskali razlike v toplotnem toku mešanic in posameznih komponent, ki smo jih na temperaturi 130 °C opazovali najmanj eno uro. Ugotovili smo, da se termogrami mešanic med seboj razlikujejo, saj se sladkorji med toplotno obdelavo obnašajo različno, kar vpliva na potek reakcij. Po končanem segrevanju je v vseh primerih prišlo do porjavenja, kar nakazuje na potek Maillardove reakcije. S pregledom literature smo povzeli, da obstaja povezava med vrsto sladkorja in nastankom akrilamida, ki je odvisna od reakcijskih pogojev. Potrdili smo, da je pri pogojih našega eksperimenta (zaprt sistem, suhi vzorci v trdi obliki, nizka vsebnost vode, povišan pritisk) glukoza v reakciji z asparaginom najbolj reaktivna, sledi ji fruktoza in nato saharoza. Ti rezultati še ne pomenijo, da je pri reakciji asparagina z glukozo nastalo več akrilamida kot pri reakciji asparagina s fruktozo oz. saharozo, saj bi za dokazovanje le tega morali analizirati nastale produkte. Saharoza ni reducirajoči sladkor, vendar je daljše segrevanje na 130 °C povzročilo reakcijo, za opredelitev katere bi bile potrebne nadaljnje raziskave. S pregledom študij smo povzeli, da so za hidrolizo saharoze potrebne višje temperature in med toplotno obdelavo živil njen vpliv na nastanek akrilamida ni bil zabeležen. Purpose of diploma thesis was to find differences between mixtures asparagine/glucose, asparagine/fructose and asparagine/sucrose when they were heated in differential scanning calorimetry system and together with an overview of literature find out and explain the connection between type of sugar and the formation of acrylamide during heat treatment of foodstuffs. We heated asparagine/sugar mixtures and individual components with constant speed of heating up to 130 °C. In separate experiment we followed changes in heat flow of mixtures and individual components while they were kept at 130 °C for at least one hour. We found out that thermograms of mixtures do differ, because sugars behave differently during heat treatment, thus influencing the reaction mechanism. After heating was completed, browning occurred in all samples, which suggests the occurrence of Maillard reaction. With literature data, we described the connection between type of sugar and formation of acrylamide, which depends on the reaction conditions. We confirmed that under conditions of our experiment (closed system, dry samples in solid form, low water content, high pressure) glucose is the most reactive sugar in the reaction with asparagine, followed by fructose and sucrose. These results do not necessarily mean that the reaction of asparagine with glucose produced more acrylamide than reaction of asparagine with fructose or sucrose, as we should analyze the products to prove that. Sucrose is not a reducing sugar, but prolonged heating at 130 °C caused some reactions that would require further research. By reviewing literature data, we concluded that higher temperatures are required for hydrolysis of sucrose and that its effect on acrylamide formation was not recorded during the heat treatment of foodstuffs.

Veneering of particleboard with ABS foil and natural oak veneer was performed using polyglycerol- and sucrose-based polyurethane adhesives. Bonding strength between veneer and underlying board was determined according to EN 312 standard. Developed adhesive formulations exhibited bonding strengths between coating material and underlying board exceeding the surface soundness of particleboard (cohesive failure between 50 % and 100 %). Higher adhesion was found for natural oak veneers. Reactivity of the studied adhesives was comparable to those for commercial adhesives used in furniture industry. It has been demonstrated that biobased polyols can be considered environmentally benign and efficient components of polyurethane adhesives for furniture industry., Furniranje ploča od usitnjenog drva ABS folijama i hrastovim furnirom provedeno je uz primjenu poliuretanskih ljepila na bazi poliglicerola i saharoze. Čvrstoća lijepljenja furnira na ploču određena je prema normi EN 312. Razvijenim formulacijama ljepila postignute su veće čvrstoće lijepljenja između prevlake i ploče nego što je međuslojna čvrstoća ploče od usitnjenog drva (kohezijski lom između 50 i 100 %). Veća adhezija zabilježena je na hrastovim furnirima. Reaktivnost ispitivanih ljepila bila je usporediva s komercijalnim ljepilima koja se upotrebljavaju u industriji namještaja. Utvrđeno je da se polioli na prirodnoj bazi mogu smatrati ekološki prihvatljivim komponentama poliuretanskih ljepila za industriju namještaja.

Cilj ovog rada je bio pripremiti bioaktivne dodatke hrani na bazi proteina smeđe riže u kombinaciji s fenolima aronije (kompleks proteini/aronija). U tu svrhu se provelo kompleksiranje proteina smeđe riže i soka aronije te kompleksiranje proteina smeđe riže, disaharida (saharoze i trehaloze) i soka aronije. Disaharidi su korišteni s ciljem utvrđivanja da li njihova prisutnost poboljšava adsorpcija fenola na proteine. Pripremljenim kompleksima određen je udio adsorbiranih fenola, proantocijanidina i antocijana. Također je određena i antioksidacijska aktivnost pomoću DPPH, ABTS, FRAP i CUPRAC metode, te parametri boje dobivenih kompleksa. Najveća količinu fenola, proantocijanidina i antocijana određena je u enkapsuliranim uzorcima nastalim kompleksiranjem proteina riže i aronije te proteina riže/trehaloze i aronije. Najveću antioksidacijsku aktivnost pokazali su enkapsulirani uzorci nastali kompleksiranjem proteina riže/aronije i trehaloze. Najmanja ukupna promjena boje uočena je kod uzoraka nastalih kompleksiranjem aronije/saharoze i proteina riže. Strukturne promjene na dobivenim kompleksima u odnosu na čisti protein određene su snimanjem IR spektra. The aim of this study was to prepare bioactive food additives based on brown rice proteins in combination with chokeberry phenols (protein/chokeberry complex). For this purpose, complexation of brown rice proteins and chokeberry juice and complexation of brown rice proteins, disaccharides (sucrose and trehalose) and chokeberry juice was performed. Disaccharides were used to determine whether their presence enhances phenol adsorption on proteins. The content of adsorbed phenols, proanthocyanidins and anthocyanins was determined on the prepared complexes. Antioxidant activity was determined using DPPH, ABTS, FRAP and CUPRAC methods. Color parameters of the obtained complexes were determined as well. The highest amount of phenol, proanthocyanidins and anthocyanins was found on encapsulated samples formed by the complexation of proteins and chokeberry and proteins/trehalose and chokeberry. The highest antioxidant activity was evaluated for encapsulated samples formed by complexation of proteins/chokeberry and trehalose. The lowest total color change was observed in samples formed by complexation of chokeberry/sucrose and rice protein. Structural changes of complexes in comparison to proteins were determined by monitoring of IR spectra.

Tibicos ili zrnca „kefirnog napitka“ sastoje se od združene kulture bakterija i kvasca te polisaharida koje proizvode navedeni mikroorganizmi. Simbiotski odnos mikroorganizama omogućava zajedničku fermentaciju i dobivanje konačnog proizvoda – „kefirnog napitka“. Zrnca korištena za uzgoj su nabavljena iz privatnog kućnog uzgoja te je njihov točan mikrobiološki sastav nepoznat. U ovom radu provedeno je optimiranje uvjeta uzgoja kefirnog napitka (temperatura, različita koncentracija saharoze). Uzgoj je proveden u prethodno steriliziranim vodenim otopinama saharoze različitih koncentracije (20 -100 g Lˉ¹) i pri različitim temperaturama uzgoja (20-40 °C). Naknadno je određen utjecaj alternativnih supstrata šećernih alkohola (eritrola i ksilitola) te stevije na metaboličku aktivnost zrna kefirnog napitka. Alternativni supstrati nisu metabolizirani što ih čini upotrebljivima kao dodana sladila u konačnoj formulaciji proizvoda. Između testiranih vrijednosti za temperaturu fermentacije i različitih koncentracija saharoze kao optimalni uvjeti određene su temperatura od 30 °C i koncentracija saharoze od 40 g Lˉ¹. Dinamika rasta zrnaca „kefirnog napitka“ i proizvodnje produkata u optimalnim uvjetima okarakterizirana je nekim osnovnim biokinetičkim parametrima (YEtOH/S = 0,012 g gˉ¹, PrEtOH = 0,016 g Lˉ¹ danˉ¹; YOctena kis./S = 0,013 g gˉ¹, PrOctena kis. = 0,018 g Lˉ¹ danˉ¹; YMliječna kis./S = 0,028 g gˉ¹, PrMliječna kis. = 0,038 g Lˉ¹ danˉ¹). Tibicos or „water kefir“ grains consist of a mixed culture of bacteria and yeast and polysaccharides produced by these microorganisms. The symbiotic relationship of microorganisms enables balanced fermentation and obtaining the final product – „water kefir“. The grains used for cultivation was obtained from private home cultivation and their exact microbiological composition is unknown. In this paper, the optimization of cultivation conditions (temperature, different sucrose concentration) was performed. The cultivation was carried out in previously sterilized aqueous solutions of sucrose of different concentrations (20 - 100 g Lˉ¹) and at different growing temperatures (20 - 40°C). The influence of alternative substrates of sugar alcohols (erythritol and xylitol) and stevia on the metabolic activity of water kefir grains was also determined. Alternative substrates are not metabolized which makes them useful as added sweeteners in the final product formulation. Between the tested values for the fermentation temperature and different sucrose concentrations, a temperature of 30°C and a sucrose concentration of 40 g Lˉ¹ was determined as optimal conditions. The dynamics of „water kefir grain“ growth and product production under optimal conditions was characterized by some basic biokinetic parameters (YEtOH/S = 0.012 g gˉ¹, PrEtOH = 0.016 g Lˉ¹ dayˉ¹; YAceti acid./S = 0.013 g gˉ¹, PrAcetic acid. = 0.018 g Lˉ¹ dayˉ¹; YLactic acid./S = 0.028 g gˉ¹, PrLactic acid. = 0.038 g Lˉ¹ dayˉ¹).

Promjene prehrambenih navika potrošača rezultirale su potrebom razvoja konditorskih proizvoda, uključujući čokoladu, u čijem sastavu je saharoza zamijenjena drugim prirodnim sladilima. Cilj ovoga rada bio je proizvesti čokolade s četiri prirodna zamjenska sladila te ispitati utjecaj njihovog dodatka na fizikalno-kemijska, bioaktivna i senzorska svojstva čokolada s 49,69% i 59,69% kakaovih dijelova. U tu svrhu u recepturama čokolada saharoza je zamijenjena agavinim i kokosovim šećerom te rižinim i ječmenim sladom. U karakterizaciji parametara čokolade primijenjene su standardne analitičke (udio vode, proteina, masti), spektrofotometrijske (udio bezmasne suhe tvari, neflavonoida, flavanoida, flavan-3-ola, proantocijanidina, antioksidacijski kapacitet), kromatografske (udio šećera, teobromina, kafeina, epikatehina) i senzorske metode. Čokolade s 59,69% kakaovih dijelova imale su bogatiji bioaktivni profil te veći udio masti, proteina, bezmasne suhe tvari kakaovih dijelova i manji udio šećera u odnosu na čokolade s 49,69% kakaovih dijelova. Primjena zamjenskih sladila povećala je bioaktivna svojstva čokolada u odnosu na čokoladu sa saharozom, što je posebno izraženo kod čokolada s 59,69% kakaovih dijelova uz dodatak rižinog slada i kokosovog šećera. Uz čokoladu s 59,69% kakaovih dijelova sa saharozom, senzorski je najbolje ocijenjena čokolada s 49,69% kakaovih dijelova s kokosovim šećerom, a najlošije čokolada s 59,69% kakaovih dijelova uz dodatak agavinog šećera. Changes in consumer eating habits have resulted in the need to develop confectionery products, including chocolate, in which sucrose has been replaced by other natural sweeteners. The aim of this study was to produce chocolates with four natural sweeteners as sucrose alternatives and to examine the effect of their addition on the physicochemical, bioactive and sensory properties of chocolates with 49,69% and 59,69% cocoa parts. To this end, sucrose chocolate in the formulations was replaced by agave sugar, coconut sugar, rice and barley malt. In the characterization of chocolate parameters, standard analytical (content of water, protein and fat), spectrophotometric (content of nonfat cocoa solids, neflavonoids, flavanoids, flavan-3-ol, proanthocyanidin, antioxidant capacity), chromatographic (content of theobromyin, caffeine and epicatehin) and sensory methods were used. Chocolates with 59,69% cocoa parts had a greater bioactive profile and a higher content of fats, proteins, nonfat cocoa solids and lower sugar content than chocolates with 49,69% cocoa parts. The use of natural sweeteners as sucrose alternatives in chocolate has increased the bioactive properties in comparison to chocolate with sucrose, which is especially pronounced in chocolates with 59,69% cocoa parts with the addition of rice malt and coconut sugar. The highest rated chocolate in sensory testing is chocolate with 59,69% cocoa parts with sucrose and chocolate with 49,69% cocoa parts with coconut sugar and the lowest rated chocolate is with 59,69% cocoa parts with agave sugar.

Cilj rada bio je utvrditi utjecaj tipa šećera (saharoze i trehaloze) i količine šećera (5 %, 10 % i 15 %) na antioksidacijsku aktivnost modelnih otopina eugenola nakon pripreme i tijekom skladištenja. Antioksidacijska aktivnost pripremljenih sustava određena je primjenom DPPH, ABTS i CUPRAC metoda. Primjenom CUPRAC i DPPH metode u modelnim otopinama eugenola s dodatkom trehaloze utvrđeno je linearno smanjenje antioksidacijske aktivnosti, a u otopinama s dodatkom saharoze linearno povećanje s povećanjem udjela dodanog šećera. Primjenom ABTS metode u oba slučaja je utvrđeno da je s povećanjem dodanog šećera došlo do povećanja antioksidacijske aktivnosti. The aim of the study was to determine the effect of the sugar type (sucrose and trehalose) and the amount of sugar (5%, 10% and 15%) on the antioxidant activity of eugenol model solutions after preparation and during storage. The antioxidant activity of the prepared systems was determined using DPPH, ABTS and CUPRAC methods. Using CUPRAC and DPPH method in eugenol model solutions with the addition of trehalose linear decrease of the antioxidant activity occurred while in solutions with addition of sucrose linear increase of antioxidant activity was observed under the same conditions. With application of ABTS method with increase of sugar amount linear increase of antioxidant activity occurred.

Prehrambeni proizvodi mogu se okarakterizirati specifičnom bojom, aromom i teksturom, a u ovom radu ispitivana je tekstura modelnih sustava guar/šećeri. U ovom radu ispitivan je utjecaj vrste šećera (saharoze i trehaloze) i količine dodanog šećera (30, 40 i 50 %) na parametre teksture modelnih sustava guar/šećeri. Ispitivani parametri teksture su bili: čvrstoća, konzistencija, kohezija i indeks viskoznosti. Rezultati istraživanja su pokazali da je povećanjem dodane količine šećera (40 % i 50 %) došlo do povećanja svih parametra teksture (čvrstoća, konzistencija, kohezija i indeks viskoznosti). Utvrđeno je da je čvrstoća veća u modelnim sustavima s dodatkom trehaloze u usporedbi s modelnim sustavima s dodatkom saharoze. Rezultati istraživanja pokazali su važanost odabira komponenata, u ovom slučaju šećera, prilikom proizvodnje ili formuliranja nekog prehrambenog proizvoda. Food products can be characterized by its specific colour, flavour and texture, and in this study texture of model systems guar/sugars was evaluated. The aim of this work was to examine the influence of sugars (sucrose and trehalose) and the amount of added sugars (30, 40 and 50%) on the textural parameters of guar gum/sugars model systems. Evaluated textural parameters were firmness, consistency, cohesiveness and index of viscosity. By increasing the added amount of sugar (40% and 50%) all textural parameters increased (firmness, consistency, cohesiveness and viscosity index). Comparison of sugar types, firmness of model systems with addition of trehalose were higher than firmness of model systems with the addition of sucrose. Results of this study showed importance of ingredients choice, in this case sugar, for preparation or formulation of food products.

Uz aromu i boju, tekstura je jedno od senzorskih karakteristika proizvoda. U ovom radu ispitivan je utjecaj vrste šećera (saharoze i trehaloze) i količine dodanog šećera (30 %, 40 % i 50 %) na promjenu parametara teksture ksantan modelnih sustava. Ispitivani parametri teksture bili su čvrstoća, konzistencija, kohezija i indeks viskoznosti. Povećanjem dodane količine šećera došlo je do povećanja svih parametara teksture. Usporedbom utjecaja tipa šećera, utvrđeno je da je čvrstoća i konzistencija veća u modelnim sustavima s dodatkom saharoze u odnosu na modelne sustave s dodatkom trehaloze. Što se tiče koheziji i indeksa viskoznosti nije utvrđena razlika ovisno o tipu šećera pri istoj dodanoj količini šećera. Rezultati istraživanja pokazali su da je povećanjem dodane količine šećera prilikom pripreme modelnih sustava došlo do linearnog povećanja parametara teksture. Next to flavour and colour, texture is one of sensory characteristics of food products. The aim of this work was to examine the influence of sugars (sucrose and trehalose) and the amount of added sugars (30%, 40% and 50%) on the textural parameters xanthan model systems. Investigated parameters were firmness, consistency, cohesiveness and index of viscosity. With increase of sugars amount addition, increase of textural parameters occurred. Comparison of type of sugar revelled that firmness and consistency of model systems with sucrose addition where higher than firmness and consistency of model systems with trehalose addition. There was no difference in the cohesiveness and viscosity index depending on the type of sugar at the same amount of sugar. The results of the study showed that with the increase of the amount of added sugar, during the preparation of the model systems, linear increase of the textural parameters occurred.

U ovom radu ispitivan je utjecaj dodatka različitih količina (5, 10 ili 20 %) disaharida (saharoze i trehaloze) na antioksidacijsku aktivnost vanilina tijekom skladištenja od 12 mjeseci pri sobnoj temperaturi. Rezultati su uspoređivani s rezultatima za kontrolni uzorak odnosno s otopinom vanilina bez dodatka šećera. Antioksidacijska aktivnost je određena primjenom ABTS, DPPH i CUPRAC metoda. Vrijednosti dobivene CUPRAC metodom su niže od vrijednosti dobivenih DPPH i ABTS metodama. Antioksidacijska aktivnost uzoraka tijekom skladištenja povećala se u odnosu na početne uzorke. Modelne otopine s dodatkom šećera imale su manju antioksidacijsku aktivnost od otopine vanilina. Povećanjem udjela dodanog šećera, bez obzira na tip šećera, antioksidacijska aktivnost se linearno povećala primjenom DPPH metode. Primjenom CUPRAC i ABTS metode u otopinama trehaloze utvrđeno je linearno smanjenje antioksidacijske aktivnosti, a u otopinama s dodatkom saharoze linearno povećanje s povećanjem udjela dodanog šećera. Rezultati ovog istraživanja pokazuju važnost odabira sastojaka prilikom formuliranja prehrambenih proizvoda obzirom da njihove interakcije mogu utjecati na antioksidacijsku aktivnost proizvoda. The aim of this research was investigation of the influence of different amounts (5, 10 or 20%) of disaccharides (saccharose and trehalose) on antioxidant activity of vanillin during storage for 12 months at room temperature. The results were compared with the results for the control sample, vanillin solution without the addition of sugar. The antioxidant activity was determined by ABTS, DPPH and CUPRAC methods. Values obtained from CUPRAC were lower than values obtained by DPPH and ABTS methods. Antioxidant activity of the samples increased during storage in regards to the initial sample. The sugar-containing solutions had lower antioxidant activity than the vanillin solution. By increasing amount of added sugar, despite of the type of sugar, antioxidant activity increased when the DPPH method was used. Using the CUPRAC and ABTS method in trehalose solutions, linear decrease of antioxidant activity was determined, while in solutions with saccharose addition linear increase occurred with increase of added sugar. Results of this research indicated importance of formulation of food products, since selected ingredients through interactions could affect antioxidant activity of the product.

U ovom završnom radu su određivane koncentracije teških metala, olova i kadmija, u realnim uzorcima meda i šećera. Na elektrodi od staklastog ugljika (GC) kronamperometrijski je formiran film hidroksiapatita (HAp) te su pomoću voltametrijskih metoda (ciklička voltametrija, pravokutnovaln a voltametrija) ispitane njegove osobine te primjena za određivanje koncentracije teških metala (olova i kadmija). Prilikom mjerenja korištene su tri elektrode: radna elektroda (GC elektroda), referentna elektroda (Ag/AgCl) i prouelektroda (platinska žica). Hidroksiapatit posjeduje veliku poroznost te sposobnost prihvaćanja drugih iona kao supstituenata. Nanošenjem ovog filma, elektrodi je povećavana osjetljivost te granica detekcije do jako niskih koncentracija teških metala. Izmjerena i određena koncentracija u šećeru za Pb iznosila je 823,7 μg/kg, dok je koncentracija izmjerena za Cd iznosila 860,0 μg/kg. Izmjerena i određena koncentracija u medu za Pb iznosila je 4410,0 μg/kg, dok je koncentracija izmjerena za Cd iznosila 387,4 μg/kg. Određene koncentracije za olovo i kadmij u oba realna uzorka premašuju vrijednosti koje su propisane Pravilnikom kao dozvoljene koncentracije tih teških metala u medu i šećeru. In this bachelor thesis, concentrations of heavy metals (Pb and Cd) are determined in real samples of sugar and honey. Hydroxyapatite (HAp) film was chronoamprometrically formed on the glassy carbon (GC) electrode and voltammetric methods (cyclic voltammetry, square wave voltammetry) were used for testing its properties and for determination of the concentrations of heavy metals (Pb and Cd). Three electrodes were used during the measurement: working electrode (GC electrode), reference electrode (Ag/AgCl) and counterelectrode (platinum wire). Hydroxyapatite has great porosity and ability to accept other ions as substituens. The presence of HAp increased the sensitivity and capacit y of GC electrode for the determination of heavy metals accurately at very low level. The concetration that we determined in sugar for the Pb is 823,7 μg/kg, while the concentration that we determined in sugar for the Cd is 860,0 μg/kg. The concentration that we determined in honey for the Pb is 4410,0 μg/kg, while the concentration that we determined in honey for the Cd is 387,4 μg/kg. The resulting concentrations of lead and cadmium in both real samples exceed the values prescribed by the Ordinance as permissible concentrations of these heavy metals in honey and sugar.

U radu su ispitivani modelni sustavi ksantan/saharoza i ksantan/trehaloza s dodatkom eugenola. Cilj rada bio je odrediti antioksidacijsku aktivnost modelnih sustava i utvrditi utjecaj tipa šećera na antioksidacijsku aktivnost eugenola u modelnim sustavima te odrediti parametre teksture. Osim toga, ispitivan je i utjecaj skladištenja na antioksidacijsku aktivnost eugenola u modelnim sustavima. Antioksidacijska aktivnost određena je DPPH, ABTS i CUPRAC metodom. Najveće vrijednosti antioksidacijske aktivnosti otopine eugenola dobivene su ABTS metodom, a najmanje CUPRAC metodom. Tip šećera, ali i metoda utjecali su na dobivene vrijednosti antioksidacijske aktivnosti. Od parametara teksture određeni su čvrstoća, elastičnost i adhezija. Vrsta šećera imala je utjecaj na parametre teksture. This paper examined the model systems of xanthan/sucrose and xanthan/trehalose with the addition of eugenol. The aim of the work was to determine the antioxidant activity of the model systems and influence of sugars on the eugenol antioxidant activity in the model systems. Also, textural parameters were determined. Antioxidant activity was determined using DPPH, ABTS and CUPRAC method. The highest values of eugenol antioxidant activity were obtained by ABTS method and the lowest by CUPRAC method. Sugar type as well as method for evaluation of antioxidant activity affected results. Hardness, elasticity and adhesion were determined as textural parameters. Textural parameters were dependent on the type of sugar.

Do pojave teških metala u medu najčešće dolazi u rudarskim i industrijskim središtima i u blizini frekventnih prometnica, gdje se teški metali apsorbiraju u tlo, atmosferu i vodu te posljedično u biljke. Također, nedostatak pojedinog elementa u tlu, stijenama ili vodi imat će utjecaj na mineralni sastav biljke. Stoga, med može služiti kao izvrstan bioindikator onečišćenja okoliša teškim metalima te obzirom na sadržaj drugih elemenata biti pokazatelj zemljopisnog podrijetla meda. U ovom završnom radu određivane su koncentracije teških metala (Cu, Pb) u zaslađivačima (medu i šećeru) pomoću metode standardnog dodatka voltametrijskih mjerenja. U tu svrhu ispitivana je uporaba hidroksiapatita (HAp) kao modifikatora na elektrodi od staklastog ugljika (GC). Uz radnu HAp/GC elektrodu, korištene su referentna (Ag/AgCl) i protuelektroda (platinska pločica). Pomoću mjernih tehnika, cikličke i pravokutnovalne voltametrije, dobiveni su potrebni podaci koji su nam poslužili za određivanje metala. Metodom standardnog dodatka te primjenom pravokutnovalne voltametrije uz optimirane parametre mjerenja određivane su koncentracije bakra i olova u medu i šećeru. Dobivena koncentracija Pb u šećeru iznosila je 823,7 μg kg -1 , dok koncentracija dobivena za Cu također u šećeru je iznosila 693,7 μg kg -1 . Dobivena koncentracija za Pb u medu iznosila je 587,5 μg kg -1 , dok koncentracija dobivena za Cu iznosila je 2775 μg kg -1 . The most common occurrence of heavy metals in honey comes in mining and industrial centers and near frequent roads where heavy metals are absorbed into the soil, atmosphere and water and consequently into the plants. Also, the lack of an element in soil, rocks or water will have an impact on the mineral composition of the plant. Therefore, honey can serve as an excellent bioindicator of heavy metals contamination of the environment and considering the content of other elements to be an indication of the geographical origin of honey. In this final work, concentrations of heavy metals (Cu, Pb) in sweeteners (honey and sugar) were determined using the standard addition method and voltammetric measurements. For this purpose, the use of hydroxyapatite (HAp) as a modifier on glassy carbon electrodes (GC) was investigated. Along with the working Hap / GC electrode, we used reference (Ag / AgCl) and (platinum plate) counter electrodes. By using measurement techniques, cyclic and square wave voltammetry, we have come up with the necessary information that serves us to determine the metal. Also, by using standard addition method, and using square wave voltammetry with optimized measurement parameters, copper and lead were determined in honey and sugar. The obtained Pb concentration in sugar was 823.7 μg kg -1 , while the concentration obtained for Cu also in sugar was 693.7 μg kg -1 . The obtained concentration for Pb in honey was 587.5 μg kg -1 , while the concentration obtained for Cu was 2775 μg kg -1 .honey, sugar

U radu su ispitivani modelni sustavi ksantan/saharoza i ksantan/trehaloza s dodatkom vanilina. Ispitivana je antioksidacijska aktivnost modelnih sustava te utjecaj tipa šećera na antioksidativnu aktivnost vanilina u modelnim sustavima te parametri teksture. Osim toga, ispitivan je i utjecaj skladištenja na antioksidativnu aktivnost vanilina u modelnim sustavima. Antioksidativna aktivnost određena je DPPH, ABTS i CUPRAC metodom. Utvrđeno je da modelni sustav ksantan/trehaloza ima veću antioksidativnu aktivnost. DPPH metodom utvrđena je najveća antioksidacijska aktivnost, a CUPRAC metodom najmanja. Tijekom skladištenja antioksidativna aktivnost sustava se je smanjila. Od parametara teksture određeni su čvrstoća, elastičnost i adhezija. Modelni sustav ksantan/saharoza imao je veće vrijednosti ispitivanih parametara u odnosu na sustav ksantan/trehaloza. Tijekom skladištenja od 12 mjeseci utvrđeno je smanjenje parametara u oba sustava. The model system xanthan/saccharose and xanthan/trehalose with the addition of vanillin were investigated in this work. The antioxidant activity of model system has been tested alongside with testing the influence of various types of sugar on the antioxidant activity of vanillin in model systems. Furthermore, texture parameters and the influence of the system's storage have also been evaluated. Antioxidant activity was evaluated by DPPH, ABTS and CUPRAC method. It has been noted that the model system xanthan/trehalose had higher antioxidant activity. The highest antioxidant activity has been found using the DPPH method and the lowest has been found using the CUPRAC method. During the storage, antioxidant activity decreased. Hardness, elasticity and adhesion were evaluated among textural parameters. Model system xanthan/saccharose had higher values of all parameters in comparison to xanthan/trehalose system. During 12 months storage all parameters decreased in both model systems.

Temperatura skladiščenja krompirja je ključna za ohranjanje kakovosti z vidika vsebnosti škroba in prisotnosti enostavnih sladkorjev. V diplomskem delu smo obravnavali vpliv dveh temperaturnih režimov (4 °C, 8 °C) skozi obdobje 41 dni pri štirih različnih sortah ('Désirée', 'Pšata', 'KIS Sora', 'KIS Krka'). Pri 4 °C smo opazili sortno občutljivost. Ena najbolj občutljivih sort je bila 'KIS Krka' z vidika ohranjanja vsebnosti škroba. Pri tej sorti se je razgradilo največ škroba v saharozo, glukozo in fruktozo. Najmanj občutljiva sorta je bila 'Désirée'. Vsebnost škroba pri 'KIS Krki' se je skozi obdobje skladiščenja pri 4 °C znižala za 13 %, enostavni sladkorji so narasli, in sicer saharoza za kar 200-krat, glukoza in fruktoza za 14-krat. Pri sorti 'Désirée' se je vsebnost škroba pri skladiščni temperaturi 4 °C skozi obdobje znižala za 21 %, saharoza je narasla za 14-krat, glukoza za 2.2-krat in fruktoza za 2.4-krat. Na podlagi rezultatov diplomskega dela smo ugotovili, da je najprimernejša temperatura skladiščenja 8 °C, kot bolj tolerantna slovenska sorta z vidika slajenja se je izkazala sorta Sora. The storage temperature of the potato is of key importance for maintaining quality in terms of the starch content and the presence of simple sugars. In the presented diploma thesis, we analysed the influence of two temperature regimes (4 C, 8 C) over a period of 41 days in four different potato varieties ('Désirée', 'Pšata', 'KIS Sora', 'KIS Krka'). By analysing the conversion of starch to single sugars, a significant difference in sensitivity to low temperatures was observed among the varieties at 4°C. One of the most sensitive varieties was 'KIS Krka' from the point of view of maintaining the content of starch over the period of sampling. In this variety, most starch is degraded into sucrose, glucose, and fructose at 4°C. The starch content decreased by 13% over the storage period at 4°C simple sugars increased by 200-fold, glucose and fructose by 14-fold. The least sensitive variety was 'Désirée'. For the 'Désirée' variety, the starch content decreased by 20.6% over the storage period at a storage temperature of 4°C, sucrose increased by 14-fold, glucose by 2.2-fold, and fructose by 2.4-fold. Based on the presented results, we found that the most suitable storage temperature for potatoes is 8°C. The most tolerant Slovenian varieties from the viewpoint of sweetening was 'Sora'.

Trehalose is an important disaccharide which takes a major role of a stress protector in many organisms, including green algae and lower plants. It has long been thought that trehalose functions in higher plants are marginal and that they have been overtaken by sucrose. In the last years it has been discovered that trehalose takes on a lot of important physiological roles in vascular plants metabolism. It is an important signal metabolite of sucrose availability and maintains sucrose concentrations within an appropriate range. It also contributes to starch synthesis and degradation and to synthesis of organic acids. Trehalose-sucrose nexus was found to be very important in plant interactions with pathogenic organisms and herbivorous insects. Furthermore, trehalose is involved in response of plant to abiotic stressors such as drought, cold, salinity and hypoxia. It contributes in regulation of stomatal conductivity where it interacts with abscisic acid. All this makes trehalose an important primary metabolite which significantly influences plant growth and development such as induction of flowering and stimulation of photosynthesis.

Cilj rada bio je ispitati termofizička svojstva modelnih sustava hidrokoloida (guara, ksantana) i šećera (saharoze, trehaloze) u temperaturnom području od -60 °C do 140 °C. Termička analiza uzoraka provedena je pomoću diferencijalnog motridbenog kalorimetra, a praćeni su parametri staklastog prijelaza, kristalizacije i taljenja. Iz rezultata se može zaključiti da su temperature faznih prijelaza kod istovrsnih sustava bile niže, što je viši udio suhe tvari. U modelnim sustavima ksantan-trehaloza razlika u srednjoj (midpoint) temperaturi staklastog prijelaza između sustava (0,6 % ksantana + 30 % trehaloze) i (0,6 % ksantana + 50 % trehaloze) iznosila je 2 °C, a u sustavima guar-trehaloza pri istim koncentracijama i manja (1,3 °C). U modelnim sustavima ksantan-saharoza pad srednje temperature staklastog prijelaza kod spomenutih koncentracija bio je 6,2 °C, odnosno 6,7 °C u sustavu guar-saharoza. Povećanjem udjela suhe tvari (dodavanjem šećera) došlo je do sniženja vrijednosti entalpija faznih prijelaza u svim uzorcima, a vrijednosti su niže u sustavima sa saharozom. U ispitivanim modelnim sustavima nije bilo značajne razlike u DSC parametrima između hidrokoloida. The aim of this study was to investigate the thermophysical properties of model systems of hydrocolloids (guar, xanthan) and sugars (sucrose, trehalose) in a temperature range from -60 °C to 140 °C. Thermal analysis of samples was performed using a differential scanning calorimeter, and the parameters of the glass transition, crystallization and melting were studied. The findings of this study indicate that the temperatures of phase transitions at the same systems were lower, with the higher the proportion of dry matter. In model systems of xanthan and trehalose difference in the midpoint glass transition temperature between the system (0.6% of xanthan + 30% trehalose) and (0.6% of xanthan + 50% trehalose) was 2 °C, and in the systems guar- trehalose at the same concentrations and lower (1.3 °C). In model systems of xanthan-sucrose drop of midpoint glass transition temperature in the mentioned concentration was 6.2 °C, and 6.7 °C in the system guar-sucrose. By increasing the content of dry substance (addition of sugars) values of the enthalpy of phase transitions in all samples were decreased. The values are lower in the system with sucrose. In the tested model systems there were no significant differences in the DSC parameters between hydrocolloids.

Šećer je neizostavan sastojak hrane, međutim pretjerana konzumacija istoga uzrokuje brojne štetne učinke za organizam, kao što su debljanje, pojavu karijesa, dijabetesa itd. Saharoza je od davnina poznata kao najviše upotrebljavani šećer u kućanstvu i u industriji. Međutim, u današnje vrijeme ljudi i industrija posežu za alternativnim prirodnim i umjetnim šećerima, kako zbog boljih tehnoloških svojstava, tako i zbog manje nutritivne i kalorijske vrijednosti. Jedni od nutritivnih sladila su i polioli, koji imaju 50 % manju energetsku vrijednost od saharoze te se zbog toga mogu kombinirati s drugim niskokaloričnim sladilima što rezultira ukusnim manje kaloričnim proizvodima. Zbog niza dobrih karakteristika kao što su stabilnost pri visokim temperaturama, ugodan i neutralan okus, otpornost na djelovanje bakterija, polioli se, osim kao sladila, upotrebljavaju kao emulgatori, krioprotektori, sredstva za stabiliziranje i vezanje vlage. Najčešće upotrebljavani su isomalt, laktitiol, maltitiol, manitol, sorbitol, ksilitol i eritrol, koji su opisani u ovome radu. Sugar is an infallible food ingredient, however the exaggerated usage of latter causes numerous harmful effects for the organism, such as obesity, caries appearance, diabetes etc. Sucrose has been always known as the most used sugar in domestic and industry activities. However, nowadays people and industry take alternative species of natural and artificial sugars because of better technologic properties and less nutritious and calorie value. One of the nutritious sweeteners is polyol which has 50% less energy value than sucrose, thus they can be combined with other low-calorie sweeteners which results low-calorie, but tasty products. Because of series of good characteristics such as stability at high temperatures, pleasant and neutral taste, resistance against bacterial activities, polyols are used, besides as sweeteners, as emulgents, cryoprotectans and as a medium for stabilization and connection of humidity. The most used are isomalt, lactitiol, maltitiol, mannitol, sorbitol, xylitol and erytrol, which are elaborated in this research.

Determination of sugars, especially in fruit juices, is very significant bearing in mind their nutritive importance and the increased demands in food control, especially for fractions of carbohydrates in fresh products. Home-made juices as 'functional food' are in the focus of scientific attention because of the expansion of industrial manufacturing of fruit juices and importance of monoand disaccharides stability for the products quality. In this work determination of content of basic sugars in fruit juices, by applying a high performance liquid chromatography (HPLC), was performed. Content of glucose, fructose and saccharose was analysed in currant, cherry, peach, apricot and strawberry juices as well as in home-made cherry and apricot syrups. Quantification was based on comparison of chromatograms of standard solutions of saccharose, glucose and fructose with our samples. With isocratic elution applied temperature was 90˚C, water as a mobile phase and column Nucleogel Sugar Ca, refractometric detection was applied. The obtained results showed that concentrations of gucose, fructose and saccharose vary in the range 3,149-38,405 g/100 mL, 1,931-30,851 g/100 mL and 0,670-6,072 g/100 mL, respectively. Concerntrations of glucose and fructose do not exhibit significant variations in juices however, they are ten times higher in syrups. In all samples, juices and syrups, concentrations of saccharose do not differ significantly, except for one syrup sample where much lower content could be explained with possible enzymatic decomposition. Određivanje šećera u voćnim sokovima je veoma važno, imajući u vidu njihov nutritivni značaj, ali i povećane zahteve u kontroli hrane kada su u pitanju pojedine frakcije ugljenih hidrata u sveže pripremljenim proizvodima. S obzirom na to da postoji porast industrijske proizvodnje voćnih sokova i značaj stabilnosti monoi disaharida za kvalitet proizvoda, domaći sokovi, kao funkcionalna hrana, postaju sve značajniji. U ovom radu je analiziran sadržaj osnovnih šećera u voćnim sokovima i sirupima kućne izrade primenom visokoefikasne tečne hromatografije (HPLC). Analiziran je sadržaj glukoze, fruktoze i saharoze u sokovima od ribizle, višnje, breskve, kajsije i jagode, kao i u sirupima od višnje i kajsije. Određivanje se zasnivalo na poređenju hromatograma rastvora standarda šećera i naših uzoraka. Uz izokratsko eluiranje analiza je izvođena pri temperaturi od 90 ˚C. Sa vodom kao mobilnom fazom i kolonom Nucleogel Sugar Ca, primenjena je refraktometrijska detekcija. Analizom je pokazano da sadržaj glukoze, fruktoze i saharoze varira u rasponu 3,149-38,405 g/100 ml, 1,931-30,851 g/100 ml i 0,670-6,072 g/100 ml, respektivno. Sadržaj glukoze i fruktoze se ne razlikuje značajno između sokova, a u sirupima je za deset puta veći. Sadržaj saharoze takođe se ne razlikuje značajno među ispitivanim uzorcima, osim u jednom sirupu zbog najverovatnije enzimske razgradnje ovog šećera.

Namen diplomskega dela je bilo proučiti reakcijske poti razgradnje različnih sladkorjev v subkritični vodi pri danem času, temperaturi in tlaku. Pri tem smo uporabili sedem različnih sladkorjev (celobioza, fruktoza, galaktoza, glukoza, ksiloza, laktoza, saharoza). Vse reakcije smo izvajali v visokotlačnem visokotemperaturnem avtoklavu pri temperaturi 250 ˚C. Reakcije v avtoklavu za posamezni sladkor smo izvajali pri treh različnih časih, 1min, 5min in 15 min. Rezultati pridobljeni s pomočjo eksperimentalnega dela so služili pri proučevanju na katere komponente se uporabljeni sladkorji pri določeni temperaturi, času in tlaku razgradijo, kakšen je posamezen delež sladkorja in ostalih spojin dobljenih pri razgradnji. Reakcijsko zmes, t.j. vodno raztopino sladkorja smo pripravili s pomočjo destilirane vode. Določili smo deleže razgradnih produktov in sicer delež v vodi topnih produktov, delež v acetonu topnih produktov, trdni preostanek ter pline in izgube. Pri eksperimentalnem delu dobljeno vodno in acetonsko fazo smo uporabili za nadaljnje analize, kot sta HPLC analiza in UV-VIS spektrofotoskopija. S pomočjo HPLC smo določili razgradne produkte posameznega sladkorja in njihove deleže glede na celotno maso vzorca. Iz dobljenih rezultatov je razvidno, da sta ena izmed glavnih produktov razgradnje sladkorjev 5-hidroksi metil furfural in furfural. Iz rezultatov je tudi razvidno, da masni delež vodne faze v odvisnosti od časa pada, medtem ko masni delež acetonske faze s časom narašča. S časom se povečuje masa trdnega ostanka in delež nastalih plinov. Delež samega sladkorja v reakciji s časom pada, kar pomeni da se sladkor razgrajuje. The prupose of diploma thesis was to study the degradation of different sugars in subcritical water at given temperature and pressure. Seven different sugars (cellobiose, fructose, galactose, glucose, xylose, lactose, sucrose) were studied. All reactions were carried out in laboratory high-pressure high-temperature autocalve. Reactions were carried out at 250 ˚C and at three different times, 1min, 5min, 15min. The results obtained were used to study the degradation products of different sugars at a certain temperature, time and pressure, the amount of sugar and other compounds derived from degradation. Reaction mixture, i.e. aqueous sugar solution was prepared by using destilled water. Mass fraction of degradation products, i.e. fraction of water soluble products, fraction of aceton soluble products, solid residue and gasses were determinated. Composition of water phase and aceton phase were analysed, with HPLC and UV-Vis spectroskopy. With HPLC analysis, decomposition products of the individual sugars and their fractions were determined. From the results it is evident that two of the main decomposition products of sugars are 5-hydroxy methyl furfural and furfural. The results also show that the percentage of the aqueous phase decreases with time, while the percentage of the acetone phase increases with time.With increasing the time of reaction mass of the solid residue and the fraction of the resulting gases increase. The fraction of sugars decreases with increasing reaction time, which means that the sugar is decomposed.

The membrane bioreactor (MBR) system was investigated regarding its nitrate removal capacity from drinking water. The performance of a pilot-scale MBR was tested, depending on the operational parameters, using sucrose as a carbon source. Drinking water from the source was introduced into the reactor in order to study the influence of flow-rate on the nitrate removal and denitrification efficiency of drinking water. The content of the nitrate was around 70 mg/L and the C/N ratio was 3:1. Nitrate removal efficiencies above 90% were obtained by flow-rates lower than 4.8 L/h. The specific denitrification rates varied between 0.02 and 0.16 g/L NO3/ (g/L MLSS.d). The efficiencies and nitrate removal were noticeably affected by the flow-rate and hydraulic retention times. At the maximum flow-rate of 10.2 L/h still 68% of the nitrate had been removed, whilst the highest specific denitrification rate was achieved at 0.2738 g/L NO3/ (g/L) MLSS.d). The maximum reactor removal capacity was calculated at 8.75 g NO3/m3.h. U radu je ispitan kapacitet membranskog bioreactora (MBR) za uklanjanje nitrata iz pijaće vode. Testirane su mogućnosti poluindustrijskog postrojenja MBR u zavisnosti od ope- rativnih parametara koristeći saharozu kao izvor ugljenika. Pijaća voda iz izvora je dove- dena u reaktor da bi se analizirao uticaj protoka na efikasnost denitrifikacije i uklanjanja nitrata iz pijaće vode. Sadržaj nitrata je bio oko70 mg/l, a odnos C/N je bio 3:1. Efikasnost uklanjanja nitrata je oko 90% pri protoku manjem od 4,8 l/h. Specifična brzina denitrifikacije je bila u opsegu od 0,02 do 0,16 g/l NO3/(g/L MLSS d). Efikasnost uklanjanja nitrata je značajno zavisila od protoka i hidrauličkog vremena zadržavanja. Pri maksimalnom protoku od 10,2 L/h moguće je uklanjanje do 68% nitrata, dok je ostvarena najveća specifična brzina denitrifikacije od 0,2738 g/L NO3/(g/L) MLSS d). Izračunato je da je maksimalni kapacitet uklanjanja nitrata 8,75g NO3/m3 h.

U sklopu ovog istraživanja provedeno je okrupnjavanje praškaste mješavine saharoze (pomoćna tvar) i azitromicin dihidrata (djelatna tvar), primjenom tehnologije granuliranja u fluidiziranom sloju taljenjem. Eksperimenti granuliranja provedeni su primjenom dviju metoda doziranja veziva: metodom raspršivanja (engl. spray-on method) s gornjeg i donjeg položaja te in-situ metodom. Vezivna tvar korištena u okviru ovog istraživanja je gliceril monostearat (GMS). Studij fenomena okrupnjavanja u laboratorijskom mjerilu usmjeren je k pronalaženju optimalnih uvjeta provedbe procesa, načina doziranja veziva i svojstava ulaznih struja materijala koji će sinergističkim djelovanjem upravljati mikro- i mezorazinskim događajima na povoljan i željeni način te time rezultirati kolektivom postojanih okrupnjenih jedinki, granula saharoze u čiju je matricu ugrađena djelatna tvar, azitromicin dihidrat. Određene raspodjele veličina čestica ispitivanih granulata ukazuju na uspješnu fizičku pretvorbu tvari (okrupnjavanje) saharoze i djelatne tvari, azitromicin dihidrata, tijekom procesa granuliranja. Važno traženo svojstvo pripremljene mješavine za tabletiranje je ujednačenost ciljanog sadržaja djelatne tvari u matrici granula neovisno o njihovoj veličini. UV/VIS spektrofotometrijska analiza korištena je pri određivanju sadržaja djelatne tvari u ispitivanim granulatima. Određeni sadržaj djelatne tvari je zadovoljavajući u svim ispitivanim veličinskim razredima. Within this study, enlargement of powdered saccharose (excipient) and azythromycin dihydrate (active pharmaceutical ingredient) mixture using fluidized bed melt granulation has been conducted. Granulation experiments have been carried out using two binder dosing methods: spray-on method (top-spray and bottom-spray positions) and in-situ method. Binder used within this research was glyceril monostearate (GMS). Study of the enlargement phenomenon in a lab-scale is focused towards detection of process conditions, binder dosing method and formulation properties that will synergically drive micro- and meso-scale events in a favourable and desired way and therewith result in a collective of stable enlarged entities, saccharose granule in which the active substance, azithromycin dihydrate, is incorporated into the matrix. Detected particle size distributions of all tested granulates indicate a successful physical conversion (enlargement) of sucrose and active substance, azithromycin dihydrate, during granulation process. An important tabletting mixture property is uniformity of the desired active substance content, azithromycin dihydrate, in the granule matrix. UV/VIS spectrophotometric analysis has been used to determine the active substance content in all observed granulates. Determined active substance content in all size fractions proved to be satisfactory.

U ovome je radu sagledano mokro granuliranje prevrtanjem kao moguća procesna tehnologija za pripravu pogodne formulacije farmaceutske tvari saharoze u svrhu dobivanja tableta dobrih primjenskih svojstava pri procesnoj tehnologiji tabletiranja. Testovi šaržnog granuliranja provedeni su prevrtanjem praškaste tvari u procesnoj geometriji kosog diska u laboratorijskom mjerilu. U fizičkoj pretvorbi tvari dodatno je korišten zrak i vezivo, vodena otopina polivinilpirolidona čiji je kolektiv kapljica dodavan raspršivanjem. Studij fenomena granuliranja u laboratorijskom mjerilu usmjeren je k pronalaženju procesnih uvjeta i sastava veziva koji će sinergističkim djelovanjem upravljati mikro- i mezorazinskim događajima na povoljan i ciljani način te time rezultirati kolektivom postojanih okrupnjenih jedinki, granula saharoze. Detektirane promjene svojstva kolektiva jedinki, raspodjele veličina čestica, s vremenom granuliranja ukazuju na doseg fizičke pretvorbe farmaceutske tvari u procesu granuliranja. Proces sadržane pretvorbe tvari modeliran je mehanističkim pristupom, primjenom populacijske bilance. Pristup modeliranja populacijskom bilancom u ovom radu podrazumijeva ispitivanje mogućnosti primjene 1-D populacijske bilance u diskretiziranom obliku te Size-Independent Kernel (SIK) modela koalescencije u simuliranju stvarne promjene raspodjele veličina čestica saharoze s vremenom. Primijenjeni pristup ukazuje na zastupljenost sadržanih mehanizama u procesu granuliranja. Metodom optimizacije, očitovanom u minimiziranju ukupne sume kvadrata odstupanja, procijenjen je karakterističan procesni parametar, konstanta brzine koalescencije. Time, kvantificirana je kinetika fizičke pretvorbe saharoze u stohastičkom okruženju kosog diska. In this thesis, wet tumble granulation is scrutinized as a potential process technology for formulation of pharmaceutical substance, saccharose in order to produce tablets with good end-use properties in a tabletting process technology. Batch granulation tests were performed by tumbling of powder substance in process geometry of inclined disc in a lab-scale. Air and binder, water solution of polyvinylpyrrolidone whose droplet population is added by spraying, are additionally used in physical conversion of a substance. Study of the granulation phenomenon in a lab-scale is focused towards detection of process conditions and binder composition that will synergically drive micro- and meso-scale events in a favourable and aimed way and therewith result in a collective of stable enlarged entities, saccharose granules. Detected changes of the property of a group of entities, particle size distribution (PSD) with respect to granulation time point to the extent of physical conversion of pharmaceutical substance within granulation process. Process of underlying conversion of a substance is modelled with mechanistic approach using population balance. Such modelling approach in this thesis implies testing the applicability of a 1-D discretized population balance with Size-Independent Kernel (SIK) coalescence model for simulation of real temporal changes of saccharose PSD. Used approach indicates the contributions of underlying mechanisms in the granulation process. Optimization method that connotes minimizing the overall sum of squared errors is used for estimation of characteristic process parameter, coalescence rate constant. Thus, kinetic of physical conversion of saccharose in a stochastic environment of an inclined disc is quantified.

U ovom radu ispitivan je utjecaj temperature (40 °C, 60 °C, 80 °C i 100 °C) na antioksidativnu aktivnost modelnih otopina fenola i šećera. Za određivanje antioksidativne aktivnosti upotrebljene su DPPH, ABTS i FRAP metode. Ispitivane su fenolne tvari katehin i kvercetin, te šećeri saharoza i trehaloza. Ispitivane su također i njihove kombinacije. U radu je izračunat i sinergistički, odnosno antagonistički učinak. Zagrijavanjem na 40 °C, u sustavima sa dodatkom šećera utvrđen je sinergistički učinak, a u sustavu bez dodatka šećera antagonistički učinak. Zagrijavanjem sustava sa katehinom na 60 °C došlo je do povećanja antioksidativne aktivnosti, dok je dodatkom šećera došlo do smanjenja. Zagrijavanjem na 80 °C, u svim sustavima je utvrđen sinergistički učinak, kao i zagrijavanjem na 100 °C. Rezultati istraživanja pokazuju važnost kemijskog sastava sustava ali i utjecaj temperature na međusobne interakcije između sastojaka sustava te utjecaj na antioksidativnu aktivnost.

U ovom radu je ispitivan utjecaj dodatka šećera saharoze, trehaloze i maltoze na sadržaj antocijana, fenola, antioksidativnu aktivnost i boju soka od šipka tijekom skladištenja pri 20 °C i 4 °C. Dodatkom šećera saharoze i trehaloze udio fenola u soku od šipka se povećao dok je najmanji udio fenola određen u uzorku sa dodatkom maltoze (827, 674 mg/L). Nakon pripreme uzoraka, najveći sadržaj antocijana imao je sok sa dodatkom maltoze (173, 460 mg/L), s tim da su i uzorci s dodatkom saharoze i trehaloze (162, 772 mg/L i 161, 854 mg/L) imali veći udio antocijana od kontrolnog uzorka (155, 500 mg/L). Pri određivanju udjela fenola i antocijana tijekom skladištenja, u svim uzorcima određen je pad ispitivane vrijednosti. Za određivanje antioksidativne aktivnosti korištene su DPPH, ABTS i FRAP metode. Kod određivanja antioksidativne aktivnosti DPPH metodom određen je pad pri skladištenju na obje temperature. Antioksidativna aktivnost određena ABTS metodom se tijekom skladištenja smanjila. Za razliku od prethodne dvije metode koje smo koristili za određivanje antioksidativne aktivnosti, kod FRAP metode na 4 °C uočeno je povećanje antioksidativne aktivnosti u svim uzorcima. Na 20 °C uočavamo pad antioksidativne aktivnosti, kao i kod prethodne dvije metode.

U ovom radu ispitivan je utjecaj dodatka različitih količina (5, 10 ili 20%) disaharida (saharoza, maltoza ili trehaloza) na udio fenola, antocijana i antioksidativnu aktivnost liofiliziranih kaša od višanja. Rezultati su uspoređivani s rezultatima za kontrolni uzorak odnosno s liofiliziranom kašom od višanja bez dodatka šećera. Najveći udio antocijana imao je kontrolni uzorak. S povećanjem udjela šećera došlo je do smanjenja udjela antocijana, osim u uzorku s dodatkom 20% maltoze koji je imao najveći udio antocijana od svih uzoraka s dodanim šećerom. Udio fenola je također bio najveći u kontrolnom uzorku a najmanji u uzorku s dodatkom 20% trehaloze. Antioksidativna aktivnost je određena primjenom ABTS, DPPH i FRAP metode. Vrijednosti dobivene primjenom ABTS metode su niže od vrijednosti dobivenih DPPH i FRAP metodama. Najveću antioksidativnu aktivnost primjenom navedenih metoda imao je uzorak s dodatkom 20% maltoze. Rezultati ovog istraživanja pokazuju da interakcije unutar kompleksnog matriksa proizvoda utječu na udio fenolnih tvari i antioksidativnu aktivnost proizvoda. The aim of this research was investigation of the influence of different amounts (5, 10 or 20%) of dissacharides (sucrose, maltose or trehalose) on phenolics, anthocyanins and antioxidant activity of freeze-dried sour cherry puree. Results were compared with control sample, freeze-dried sour cherry puree without addition of sugars. The highest anthocyanin content had control sample. With increase of sugar addition, increase of anthocyanin content was observed except in the case of addition of 20% of maltose. That sample had the highest anthocyanin content among samples with sugar addition. The highest phenol content was also determined in control sample, while the sample with 20% of trehalose addition had the lowest content. Antioxidant activity was determined by ABTS, DPPH I FRAP methods. Values of antioxidant activity determined by ABTS were lower in comparison to values obtained by FRAP and DPPH method. The highest antioxidant activity (determined with all methods) had sample with addition of 20% of maltose. Results of this research showed that interactions among food component play important part on phenolics and antioxidant activity.

Svojstva koja čine tablete jednim od najboljih oblika gotovih lijekova su jednostavan način primjene i mogućnost preciznog doziranja djelatne tvari u tabletu prilikom proizvodnje kao i u liječenju. Kvalitetnim izborom pomoćnih tvari i primjenom tehnoloških postupaka moguće je oblikovati različite vrste farmaceutskih oblika te utjecati na svojstva gotovih tableta. Cilj ovog rada bio je ispitivanje utjecaja sastava mješavina za tabletiranje na svojstva gotovih tableta i ujednačenost sadržaja djelatne tvari, omeprazola. U eksperimentu je korišteno sedam komponenata iz kojih je pripremljeno pet različitih mješavina za tabletiranje. Kao osnovna komponenta u svim mješavinama korištena je granulirana saharoza dobivena granuliranjem usitnjene saharoze p.a. uz dodatak veziva polivinilpirolidona (PVP). Mikrokristalinična celuloza (MCC), manitol, laktoza te PanExcea MC200G izvorna i granulirana, korištene su kao sredstva za dopunjavanje u mješavinama. U svaku mješavinu kao sredstvo za klizenje dodano je 3 % magnezijevog stearata. Pojedinačnim komponentama i mješavinama određena je raspodjela veličina čestica, kut mirovanja, nasipna gustoća i gustoća nakon sabijanja te su izračunati indeksi kompresibilnosti i Hausnerov omjer. Postupak tabletiranja proveden je na ekscentričnoj tabletirki s jednim parom klipova te je na dobivenim tabletama ispitana raspadljivost, tvrdoća, dimenzije i rastrošljivost. Odabirom najpogodnije mješavine i tablete najboljih karakteristika dobivena je osnova za dodatak djelatne tvari, omeprazola. Omeprazol je dodan na dva načina, u procesu miješanja i u procesu granuliranja u fluidiziranom sloju. Osim provedenih standardnih testova karakterizacije, na dobivenima tabletama omeprazola provedeno je ispitivanje sadržaja djelatne tvari u 10 nasumično odabranih tableta. Rezultati su pokazali značajan utjecaj raspodjele veličina čestica na svojstva mješavina, a time i na karakteristike tableta. Granuliranje se pokazalo kao ključan korak u procesu izrade tableta jer je postignuta pogodna raspodjela veličina čestica, bolja tecivost mješavina, veća tvrdoća tablete te ujednačeniji sastav omeprazola u tabletama čime se osigurava točnost doziranja djelatne tvari. Tablets are the most suitable dosage forms due to the simplicity of use and the possibility of precise dosage of the active ingredient in the tablet during production as well as in treatment. Good selection of excipients and process technologies formulate different types of pharmaceutical dosage forms and affects the properties of the tablet. The aim of this study was to investigate the influence of the mixture composition on tablet properties and to ensure that each tablet contains the correct amount of active ingredient, omeprazole. Five different mixtures were prepared for tableting from seven components. All mixtures contained sucrose that was granulated in fluid-bed with a binder polyvinylpyrrolidone (PVP). Microcrystalline cellulose (MCC), mannitol, lactose and PanExcea MC200G, original and granulated, were used as fillers in prepared mixtures. Magnesium stearate (3 %) was added in each mixture as a glidant. The individual components and mixtures were characterized by the particle size distribution, angle of repose, bulk density and tapped density as well as calculated compressibility index and Hausner ratio. The tableting process was carried out in an eccentric tableting machine with a pair of pistons. Obtained tablets were tested on dissolution, hardness, dimensions and friability. The most appropriate mixture and the tablets of best quality were chosen as the basis for the addition of active substance, omeprazole. Omeprazole was added to the mixture in the process of simple powder blending and granulation process in a fluid-bed. Tablets were subjected to standard characterization tests, and additionally, omeprazole content was determined in 10 randomly selected tablets. The results revealed a significant effect of particle size distribution on the properties of a mixture, and thus the characteristics of tablets. It was shown that the granulation is a crucial step in the tableting process. Granulated materials achieved suitable particle size distribution, better flowability, greater hardness of tablets and more uniform composition of omeprazole in tablets thus ensuring the accuracy of dosage of the active ingredient.

Ogrodne tablete so peroralna farmacevtska oblika, s pomočjo katere doseţemo podaljšano sproščanje, najpogosteje z nabrekanjem hidrofilnega polimera v stiku s črevesnimi sokovi. Ob prehodu skozi gastrointestinalni trakt je taka tableta podvrţena različnim pogojem (pH, peristaltika), na sproščanje pa lahko vplivata tudi zauţita hrana in pijača. Namen te naloge je bil opredeliti vpliv kombinacije različnih koncentracij saharoze in pektina v mediju, na sproščanje iz ogrodnih tablet s hidroksipropilmetil celulozo (HPMC). Poskuse smo izvedli na dveh različnih vrstah tablet, ki smo jih izdelali sami. Tablete so vsebovale paracetamol (modelna učinkovina), mikrokristalno celulozo, magnezijev stearat ter HPMC. Polovica tablet je vsebovala HPMC vrste Metolose® 65SH-4000, druga polovica pa Metolose® 90SH-100 000 SR. Poskuse smo izvajali na pretočnem sistemu s kroglicami. Vodni mediji so vsebovali 0,002M HCl ter saharozo ali pektin v različnih koncentracijah ter kombinacijah. Mediji s saharozo so vsebovali saharozo v koncentracijah 150, 200, 250 ali 300 g/L, medij s pektinom je vseboval koncentracijo pektina 5 g/L, kombinirani mediji pa so vsebovali navedene koncentracije saharoze in koncentracije pektina 1, 2 ali 5 g/L. Ugotovili smo, da uporabljeni vrsti HPMC različno reagirata na povišanje koncentracije saharoze. HPMC Metolose® 65SH-4000 je na višanje koncentracije saharoze bolj občutljiva, do hitrega sproščanja iz tablet s to vrsto HPMC je prišlo ţe pri koncentraciji saharoze 200 g/L, medtem ko so tablete s HPMC (Metolose® 90SH-100 000 SR) izkazovale hitro sproščanje šele v mediju s koncentracijo saharoze 300 g/L. Koncentracija pektina 5 g/L v mediju na sproščanje iz tablet s HPMC Metolose® 65SH-4000 ni vplivala, pri tabletah s HPMC Metolose® 90SH-100 000 SR pa se je hitrost sproščanja nekoliko povečala. Sproščanje paracetamola v kombiniranih medijih, je bilo glede na profil sproščanja v mediju s saharozo spremenjeno pri obeh vrstah tablet enako. S povečevanjem koncentracije pektina do 2 g/L se je hitrost sproščanja paracetamola zmanjševala. Pri koncentraciji pektina 5 g/L pa se je sproščanje ţe občutneje upočasnilo. Matrix tablet is an oral dosage form, which ensures prolonged release, most frequently by swelling of hydrophilic polymer when it comes in contact with gastric juice. While the tablet passes the gastrointestinal tract it is exposed to different conditions that could affect drug release. The release is also influenced by food and drinks one consumes. The main goal of this thesis was to define effects of different concentrations of sucrose and pectin in media on drug release from matrix tablets with hydroxypropylmethyl cellulose (HPMC). The experiments were performed on two different types of tablets, which we made ourselves. Tablets contained paracetamol as a model substance, microcrystalline cellulose, magnesium stearate and HPMC. One type of the tablets contained HPMC Metolose® 65SH-4000, and the other type contained HPMC Metolose® 90SH-100 000 SR. The experiments were performed on a flow-through system with glass beads. Aqueous medium contained 0,002 M HCl and sucrose and pectin in different concentrations and combinations. Media with sucrose contained sucrose in concentrations 150, 200, 250 or 300 g/L, the medium with pectin contained a concentration of pectin 5 g/L, and the combined media contained above cited concentrations of sucrose and pectin in concentrations 1, 2 or 5 g/L. We concluded that both types of HPMC react differently when the concentration of sucrose increases. HPMC Metolose® 65SH-4000 is more susceptible to increasing the concentration of sucrose drug release from tablets was fast, starting at concentration of sucrose 200 g/L. HPMC Metolose® 90SH-100 000 SR tablets started to release faster at the concentration 300 g/L of sucrose in the medium. On one hand, adding only pectin to the medium at concentration 5 g/L did not affect the release from tablets with HPMC Metolose® 65SH-4000. On the other, this concentration of pectin slightly increased the release rate from tablets with HPMC Metolose® 90SH-100 000. The release of paracetamol in sucrose media was changed (for both types of tablets) when we added pectin. With increasing the concentration of pectin up to 2 g/L in sucrose media, the release rate of paracetamol decreased. Concentration 5 g/L of added pectin significantly slowed down the release.

U radu je ispitivana antioksidativna aktivnost modelnih otopina fenolnih tvari s dodatkom saharoze te međusobni utjecaj fenolnih tvari na antioksidativnu aktivnost odnosno sinergijski učinak. Fenolne tvari koje su ispitivane su katehin, kvercetin i galna kiselina te njihove kombinacije. Za određivanje antioksidativne aktivnosti primijenjene su ABTS, DPPH i FRAP metode. Navedenim metodama utvrđeno je da otopina katehina, kvercetina i galne kiseline s dodatkom saharoze ima najveću antioksidativnu aktivnost. Najmanju antioksidativnu aktivnost imaju uzorci pojedinačnih fenolnih tvari. ABTS i DPPH metodom najmanju antioksidativnu aktivnost ima otopina katehin. Najmanju antioksidativnu aktivnost FRAP metodom ima otopina galne kiseline. Sinergijski učinci kod ABTS, DPPH i FRAP metode različiti su za različite uzorke. The subject of this work was evaluation of antioxidant activity of model solutions of phenolic compounds with addition of sucrose and mutual influence of phenolic substances on an antioxidant activity i.e. synergistic effect. Phenolic compounds which have been tested were catechin, quercetin, gallic acid and their combinations. ABTS, DPPH and FRAP methods have been applied to determine antioxidant activity. Using ABTS, DPPH and FRAP methods it has been found that solution of catechin, quercetin and gallic acid with addition of sucrose had the highest antioxidant activity. Samples of single phenolic substances have the lowest antioxidant activity. According to the results obtained via the ABTS and DPPH methods, the solution of catechin has the lowest antioxidant activity. According the results obtained via the FRAP method, the solution of gallic acid has the lowest antioxidant activity. Synergistic effects of ABTS, DPPH and FRAP methods have been different for different samples.