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Function of the HACCP system in the production of traditional Slavonian kulen : bachelor thesis
No full text1.siječnja 2009. Godine na snagu je stupila Odredba Zakona o hrani (NN 46/07) prema kojoj su svi subjeki u poslovanju s hranom dužni uspostaviti sustav upravljanja sigurnošću hrane koji će se temeljiti na principima HACCP sustava. Sukladno s navedenim svi subjekti u poslovanju s hranom do tog datuma bili su dužni uspostaviti i implementirati HACCP sustav u svoje proizvodne pogone. Prilikom uspostave ove odredbe javljale su se mnoge poteškoće koje su rezultirale odugovlačenjem uspostave HACCP sustava, neprovođenjem propisanih mjera te neadekvatnim održavanje HACCP sustava. Sve ove poteškoće dovodile su do onemogućavanja svrsishodnog djelovanje što je moglo rezultirati narušavanjem kvalitete krajnjeg prehrambenog proizvoda te ugrožavanjem zdravlja potrošača. Primarni zadatak ovog rada bio je objasniti provođenje pojedinih koraka od kojih se HACCP sustav sastoji na primjeru proizvodnje tradicionalnog Slavonskog kulena.On 1 January 2009, the Provision of the Food Act (OG 46/07) entered into force, according to which all food business operators are obliged to establish a food safety management system based on the principles of the HACCP system. In accordance with the above, all entities in the food business by that date were required to establish and implement the HACCP system in their production facilities. During the establishment of this provision, many difficulties arose which resulted in delays in the establishment of the HACCP system, non-implementation of prescribed measures and inadequate maintenance of the HACCP system. All these difficulties led to the impossibility of purposeful action, which could have resulted in the deterioration of the quality of the final food product and endangering the health of consumers. The primary task of this paper was to explain the implementation of individual steps of which the HACCP system consists of the example of the production of traditional Slavonian kulen
Synthesis and analysis of organic compounds with sulfur and/or nitrogen: pyridopyridazines and glucosinolates : diploma thesis
No full textOrganske molekule s dušikom i/ili sumporom, zbog svoje vrlo široke primjene u medicini, sve su veći predmet istraživanja. Prvi dio diplomskog rada bavi se sintezom piridopiridazina, spojeva s dušikom, koji posjeduju široku biološku aktivnost (antibakterijsko, antihipertenzivno, antikonvulzantno djelovanje, itd.). Drugi dio diplomskog rada bavi se glukozinolatima (β-tioglukozidni-N-hidroksisulfati) spojevima sa sumporom i dušikom, koji su pronađeni u porodicama reda Capparales. Ovi spojevi karakteristični su za biljke u porodici Brassicaceae. Hidrolizom glukozinolata enzimom mirozinazom nastaje čitav niz različitih biološki aktivnih razgradnih produkata od kojih su najpoznatiji izotiocijanati, poznati po sovjim antikancerogenim i antimikrobnim svojstvima. U ovom radu uspješno su sintetizirana 4 piridopiridazina, jedan osnovni (5-metil-7-fenil-2,3- dihidropirido[3,4-d]piridazin-1,4-dion, uz iskorištenje od 50,4%) i 3 njegova derivata. Sintetizirani međuprodukti praćeni su tankoslojnom kromatografijom, a struktura konačnih produkata potvrđena je infracrvenom spektroskopijom i nuklearnom magnetskom rezonancijom. Također, istražen je kvalitativni sastav glukozinolata u dvije biljne vrste, širolistnoj grbici (Lepidium latifolium L.) i sivkastoj ljubičini (Matthiola incana (L.) R.Br.). Analziom sa HPLC-DAD- MS/MS tehnikom utvrđeno je da L. latifolium sadrži sinigrin kao glavni glukozinolat, dok je u M. incana pronađen glukorafenin. U okviru daljnjeg istraživanja ispitana je stabilnost glukozinolata pri gastrointestinalnim uvjetima, te pH (2,5 i 7,5). Glukozinolati su pokazali stabilnost u kiseloj i želučanoj fazi, a nestabilnost u lužnatoj i crijevnoj fazi, uz "poneka" odstupanja. Kvantitativni sastav glukozinolata određen je HPLC analizom desulfatiziranih glukozinolata.There is an increase interest in organic molecules containing nitrogen and/or sulfur in their structure, due to their very broad application in medicine. The first part of the thesis deals with the synthesis of pyridopyridazines, nitrogen compounds, which possess a wide range of biological activities (antibacterial, antihypertensive, anticonvulsant, etc.). The second part of the thesis deals with glucosinols (β-thioglucoside-N-hydroxysulphates) with sulfur and nitrogen compounds found in Capparales family. These compounds are characteristic for plants in the family Brassicaceae. Glucosinolates hydrolyzed by the enzyme myrosinase produce a wide variety of biologically active degradation products, most notably isothiocyanate, known for their anticancerogenic and antimicrobial activity. In this paper four pyridopyridazines, one "basic" (5-methyl-7-phenyl-2,3-dihydropyrido [3,4-d] pyridazine-1,4-dione, with a yield of 50.4%) and 3 of its derivative were successfully synthetized. The synthesized intermediates were monitored by thin layer chromatography, and the final product structure was confirmed by IR and NMR. Also, the qualitative composition of glucosinolates was investigated in two plant species, Lepidium latifolium L. and Matthiola incana (L.) R.Br. By the HPLC-DAD-MS/MS technique, it was found that L. latifolium contains as the major glucosinolate sinigrin, while M. incana contains glucoraphenine. Within the scope of further research the stability of glucosinolates in gastrointestinal conditions and pH (2.5 and 7.5) was studied. Glucosinolates showed stability in the acid and gastric phase, and instability in the alkaline and intestinal phases, with some deviations. The quantitative composition of glucosinolates was determined by HPLC analysis of desulfated glucosinolates
Determination of heavy metals in garden candytuft and rocket seeds : diploma thesis
No full textU ovom diplomskom radu određene su koncentracije odabranih teških metala u sjemenkama štitaste ognjice (Iberis umbellata L.) i rukule (Eruca sativa Mill.). Koncentracije odabranih teških metala su određene diferencijalnom impulsnom anodnom "stripping" voltamterijom (DPASV). Uočava se kako su najniže koncentracije teških metala detektirane za kadmij te iznose 0,06 μg g-1 za štitastu ognjicu te 0,44 μg g-1 za rukolu. Detektirane su jako niske koncentracije olova u sjemenkama biljaka dok su se koncentracije cinka nalazile unutar odgovarajućih granica te u štitastoj ognjici iznosile 34,20 μg g-1, dok su u rukoli bile 39,80 μg g-1. Koncentracije bakra u sjemenkama obiju biljaka su bile ispod odgovarajućih vrijednosti koje su potrebne za rast i razvoj biljke.In this graduate thesis the concentrations of selected heavy metals were determined in the seeds of the garden candytuft (Iberis umbellata L.) and the rocket (Eruca sativa Mill.). The concentrations of selected heavy metals are determined by differential impulse anode "stripping" volatility (DPASV). It is noted that the lowest concentrations of heavy metals were detected for cadmium, 0.06 μg g-1 for garden candytuft and 0.44 μg g-1 for rocket. Very low concentrations of lead in plant seeds were detected, while the zinc concentrations are within the permissible limits, in the garden candytuft is 34.20 μg g-1 while in the rocket 39.80 μg g-1. The concentrations of copper in the seeds of both plants were below the compatible values required for the growth and development of the plant
ZnO nanostructured photocatalysts for water treatment applications : diploma thesis
No full textPoluvodički materijali metalnih oksida, dizajnirani za primjenu u fotokatalitičkim sustavima za pročišćavanje vode, moraju imati veliku specifičnu površinu jer se kemijske reakcije inducirane odgovarajućim zračenjem odvijaju na sučelju površine i tekućine. Cinkov oksid poznat je po mnoštvu morfologija na mikro- i nanoskali, koje lako mogu ispuniti ovaj zahtjev pod utjecajem ultraljubičastog zračenja. Neke morfologije na nanoskali čine cinkov oksid funkcionalnim fotokatalizatorom i na suncu. Fotokatalitička degradacija organske boje, kao modelnog onečišćivala, proučavana je u vodenim otopinama korištenjem struktura cinkovog oksida sintetiziranih u obliku prizmi, štapova i vlati (žica). Rasle su iz otopine, a njihova je cjelovita morfologija kontrolirana uvjetima rasta. Njihova morfologija na mikro- i nanoskalidetaljno je karakterizirana pomoću skenirajuće elektronske mikroskopije te difrakcijei raspršenja X-zraka. Sve strukture pokazale su značajnu fotokatalitičku aktivnost. Međutim, izuzetni rezultati postignuti su s nanostrukturama u obliku vlati, koje su pokazale pojačanu fotokatalitičku aktivnost na sunčevom svjetlu. To je pripisano njihovoj specifičnoj morfologiji s defektima i visokim stupnjem mezoporoznosti.Metal oxide semiconductor materials, designed to be applied in photocatalytic systems for water purification, are required to have large specific surface areas, because chemical reactions induced by suitable irradiation take place by contact between their surface and fluid. Zinc oxide is well known as a material that forms various morphologies at the micro- and nanoscale, which can easily fulfill this requirement in the case of ultraviolet irradiation. However, some nanoscaled morphologies can also provide zinc oxide catalysts that are functional in the sunlight. Photocatalytic degradation of an organic dye, as a model pollutant, was studied in aqueous solutions using structures of zinc oxide synthesized in the form of prism, spiky stick and grass blade. They were grown from a solution and their entire morphology was simply controlled by varying the growth conditions. Detailed characterization of their morphology on the micro- and nanoscale was performed by scanning electron microscopy and X-ray diffraction and scattering measurements. All structures exhibited notable photocatalytic activity. However, remarkable results were achieved with nanostructures in the form of grass blade, which exhibited enhanced photocatalytic activity in sunlike light. This was ascribed to their specific morphology characterized with defects and a high degree of mesoporosity
The influence of waste concrete addition on specific electrical conductivity of cement paste : bachelor thesis
No full textU ovom radu provedeno je određivanje specifične električne provodnosti cementnih pasti, bez dodatka i uz dodatak 5-30 mas. % otpadnog betona. Mjerenja su provedena u termostatu pri temperaturi od 20 ℃ i pri vodocementnom, V/C = 0,5 i voda/kruto omjeru V/K = 0,5. Sve dobivene krivulje ovisnosti specifične električne provodnosti o vremenu hidratacije cementnih pasti imaju sličan grafički oblik s naglašenim vrhom maksimalne provodnosti. Vrijeme početka vezivanja za pojedini tip cementa odgovara vremenu pojave maksimalne specifične provodnosti. Iz rezultata se može zaključiti da dodatak otpadnog betona uzrokuje pad vrijednosti specifične električne provodnosti te su maksimumi pomaknuti prema kasnijim vremenima hidratacije. Također je uočena velika razlika u rezultatima specifične električne provodnosti između uzoraka portland cementa CEM I 42,5 R ULTIMO i TECNOCEM-a.In this paper, the determination of the specific electrical conductivity of the cement pastes was carried out without the addition and with addition 5-30 wt.% of waste concrete. The measurements were carried out in a thermostat at 20 °C and at the water/cement ratio, W/C=0,5 and water/solid ratio, W/S=0.5. All obtained curves of specific electrical conductivity dependence on the hydration time of the cement paste have a similar graphical shape with a pronounced peak of maximum conductivity. The start of binding time for a particular type of cement corresponds to the time of occurrence of maximum specific conductivity. From the results it can be concluded that the addition of waste concrete decreases specific electrical conductivity values. Also, a large difference in specific electrical conductivity results was observed between the Portland cement samples CEM I 42,5 R ULTIMO and TECNOCEM
Influence of drying temperature on preparation of poly(ethylene oxide) films : bachelor thesis
No full textPriprava poli(etilen-oksid) (PEO) filmova različitih molekulnih masa provedena je izlijevanjem filmova iz vodenih otopina različitih koncentracija, pri čemu su istraživani optimalni uvjeti otapanja polimera u vodi. Uspješno pripravljene otopine podvrgnute su sušenju pri čemu je cilj bio pronaći i optimalne uvjete sušenja, tj. postupak priprave kvalitetnih suhih filmova. Diferencijalna pretražna kalorimetrija (DSC) je primijenjena u istraživanju utjecaja različitih molekulnih masa, debljina filmova i temperatura sušenja u vakuum sušioniku na toplinska svojstva i kristalnost PEO-a. Uočilo se nastajanje različitih kristala PEO-a u istraživanim filmovima, te se može reći da se određene toplinske značajke filmova značajno ne razlikuju. Toplinska postojanost filmova istraživana je primjenom neizotermne termogravimetrije (TG). Filmovi PEO-a razgrađuju se u jednom stupnju razgradnje i nema razlike u toplinskoj postojanosti filmova obzirom na utjecaja različite temperature sušenja u vakuum sušioniku, različitih molekulnih masa i koncentracija polimernih otopina. Ostvaren je glavni cilj istraživanja koji se odnosi na uspješno uklanjanje otapala iz filmovaThe preparation of poly(ethylene oxide) (PEO) films of different molecular weights was carried out by casting the films from aqueous solutions of different concentrations, where the optimal conditions for dissolving the polymer in water were investigated. Successfully prepared solutions were subjected to drying, with the aim of finding optimal drying conditions, i.e. the process of preparing quality dry films. Differential scanning calorimetry (DSC) was applied to investigate the influence of different molecular weights, film thicknesses and drying temperatures in a vacuum dryer on the thermal properties and crystallinity of PEO. The formation of different PEO crystals was observed in the investigated films, and it can be said that certain thermal characteristics of the films doesn’t differ significantly. The thermal stability of the films was investigated using non-isothermal thermogravimetry (TG). PEO films are digested in one stage of decomposition and there is no difference in the superior film stability due to the influence of different drying temperatures in vacuum drying, different molecular weights and concentrations of polymer solutions. The main goal of the research related to the successful removal of solvents from films has been achieved
Chemical analysis of drinking water : bachelor thesis
No full textVoda je jedinstveni kemijski spoj te zauzima najveći dio planete Zemlje. Iako se Zemlja naziva „Plavi planet“ dostupnost i zalihe pitke vode su ograničene. Kakvoća vode za piće prati se veličinom pojedinih pokazatelja (kemijskih, fizikalnih i bioloških) koji govore o sastavu, koncentraciji i svojstvima pojedinih tvari prisutnih u vodi, a koji su propisani pravilnicima, uredbama i zakonima. Voda koja se upotrebljava za piće mora biti bez štetnih tvari i zdravstveno ispravna. Značajne karakteristike Cetine, kao što su mali sadržaj otopljenog ugljikovog dioksida, dobro zasićenje kisikom te umjerena tvrdoća čine ovu vodu pogodnom za vodoopskrbu stanovništva na području srednjodalmatinskih otoka, Omiša i primorja Makarske. Voda izvora Jadra je kalcijsko-bikarbonatnog tipa, sadrži malo otopljenog ugljikovog dioksida i male je mineralizacije. Najveći potrošač vode s izvora Jadra je grad Split.Water is a unique chemical compound and occupies most of the planet Earth. Although the Earth is called the „Blue Planet“, the availability and supply of drinking water is limited. The quality of drinking water is monitored by the size of individual indicators (chemical, physical and biological) which speak about the composition, concentration and properties of certain substances present in the water, which are prescribed by regulations, ordinances and laws. The water used for drinking must be free of harmful substances and healthy. Significant characteristics of the Cetina, such as low content of dissolved carbon dioxide, good oxygen saturation and moderate hardness make this water suitable for water supply to the population in the area of the central Dalmatian islands, Omiš and the coast of Makarska. The water from the Jadra spring is of the calcium-bicarbonate type, contains little dissolved carbon dioxide and has low mineralization. The biggest water consumer of the source Jadra is city Split
Multi-stage leachate treatment from municipal waste landfill Bikarac using lime, aeration and Fenton process : diploma thesis
No full textU ovom radu je provedena fizikalno-kemijska karakterizacija procjedne vode s odlagališta otpada Bikarac te njena obrada primjenom vapna, aeracije i Fenton procesa. Rezultati su pokazali da nakon obrade vapnom i aeracije vrijednosti pokazatelja pH i KPK su iznad MDK vrijednosti propisanih Pravilnikom te se obrađena procjedna voda ne može ispustiti u sustav javne odvodnje. Ispitan je utjecaj pH, koncentracije Fe 2+ iona i H 2 O 2 , molarnog koncentracijskog omjera Fe 2+ :H 2 O 2 te vremena kontakta na smanjenje KPK vrijednosti primjenom Fenton procesa. Najučinkovitije smanjenje KPK primjenom Fenton procesa u iznosu od 40% postignuto je pri optimalnim uvjetima procesa: pH = 3 i molarnom koncentracijskom omjeru Fe 2+ :H 2 O 2 =1:20 te koncentracije Fe 2+ od 9 mg/L. Kinetički rezultati su ukazali da je kinetika razgradnje organskih tvari iz procjedne vode iznimno složena. Primjenom Fenton procesa postigli su se uvjeti za ispust obrađene procjedne vode u površinske vode.In this paper, the physico-chemical characterization of leachate from the Bikarac landfill and its treatment using lime, aeration and Fenton process was performed. The results showed that by applying lime and aeration the values of pH and COD are above the permissible limits prescribed by the Croatian legislative and treated leachate cannot be discharged into the public system. The influence of pH, concentration of Fe 2+ ions and H 2 O 2 , molar concentration ratio of Fe 2+ :H 2 O 2 and contact time on the decreasing of COD values using the Fenton process was also investigated. The most effective decreasing of COD using Fenton-like process in the amount of 40% was achieved under optimal process conditions: pH=3 and molar concentration ratio Fe 2+ :H 2 O 2 =1:20 and concentration of Fe 2+ was 9 mg/L. The kinetic results indicated that the kinetics of decomposition of organic matter from leachate is extremely complex. By applying the Fenton process, the conditions for the discharge of treated leachate into surface waters were achieved
Synthesis and characterization colloid silver obtained the electrochemical method of low voltage direct current : diploma thesis
No full textU ovom radu proučavano je dobivanje koloidnog srebra elektrokemijskom metodom niskog istosmjernog napona. Primijenjene su dvije srebrene elektrode čistoće 99,99 %, promjera 3,0 mm, staklena čaša s 200 cm 3 destilirane vode i spojni vodovi od izvora istosmjerne struje do elektroda. Kao izvor istosmjerne struje korišten je laboratorijski ispravljač te generator koloidnog srebra. Kao prirodni stabilizator korištena je karuba guma sintetizirana iz sjemenki rogača. Provjera pojave koloidnog srebra i procjena koncentracije srebra u otopini određena je propuštanjem laserske zrake kroz otopinu. Karakterizacija koloidnog srebra (nanočestica srebra) provedena je UV-Vis spekroskopijom te primjenom transmisijskog elektronskog mikroskopa. Primjenom elektrokemijske metode, uz ispravljač i generator kao izvor istosmjerne struje, može se proizvesti koloidno srebro zadovoljavajuće kvalitete. UV-Vis analiza potvrdila je površinsku plazmonsku rezonanciju nanočestica srebra. Primjenom PWHM metode procijenjena je veličina nanočestica srebra i kreće se u rasponu od 30-50 nm. TEM analizom uočeno je da su nanočestice srebra sferičnog oblika, osim u uzorku E1 gdje su čestice u obliku štapića i mikrometarskih dimenzija. Veličina čestica u ostala tri uzorka se kretala u rasponu od 23-52 nm. TEM analiza potvrdila je procijenjenu veličinu nanočestica srebra dobivenu PWHM metodom. Dodatak karuba gume kao prirodnog stabilizatora nema utjecaj na veličinu nanočestica srebra.In this paper, the production of colloidal silver by the electrochemical method of low voltage direct current was studied. Two silver electrodes of 99.99% purity, 3.0 mm diameter, a glass beaker with 200 cm 3 of distilled water and connecting wires from a direct current source to the electrodes were used. A laboratory rectifier and a colloidol silver generator were used as a source of direct current. As a natural stabilizer, carob gum synthesized from carob seeds was used. Checking the occurrence of colloidal silver and estimating the concentration of silver in the solution was determined by passing a laser beam through the solution. Characterization of colloidal silver (silver nanoparticles) was performed by UV-Vis spectroscopy and using a transmission electron microscope. By applying the electrochemical method, with a rectifier and a generator as a source of direct current, colloidal silver of satisfactory quality can be produced. UV-Vis analysis confirmed the surface plasmon resonance of silver nanoparticles. Using the PWHM method, the size of silver nanoparticles was estimated and ranged from 30-50 nm. TEM analysis showed that the silver nanoparticles are spherical in shape, except in sample E1 where the particles are rod-shaped and micrometer-sized. The particle size in the other three samples ranged from 23-52 nm. TEM analysis confirmed the estimated size of silver nanoparticles obtained by the PWHM method. The addition of carob gum as a natural stabilizer has no effect on the size of silver nanoparticles
Classic and microwave-assisted synthesis of 4-nitrophenyl-isothiocyanate : diploma thesis
No full textIzotiocijanati (ITC) se klasificiraju kao posebna skupina hlapljivih sumporovih spojeva koji prirodno nastaju enzimskom hidrolizom glukozinolata djelovanjem enzima mirozinaze pri neutralnoj pH vrijednosti kada dolazi do Lossenove pregradnje nestabilnog meĊuprodukta. Istraživanja su pokazala da ova grupa spojeva posjeduje izražena antikancerogena, antibakterijska i antimikrobna svojstva. Zbog svoje biološke aktivnosti, izotiocijanati su postali interes velikog broja znanstvenika te su razvijene brojne metode njihove sinteze. Cilj ovog rada bila je sinteza p-nitrofenil-izotiocijanata reakcijom odgovarajućeg aminskog supstrata s ugljikovim disulfidom uz prisustvo baze. Sinteza u prvom koraku daje ditiokarbaminsku sol koja podliježe eliminaciji djelovanjem desulfurizacijskog reagensa (cijanurinska kiselina) pri ĉemu dolazi do formiranja odgovarajućeg produkta. Na ovakav se naĉin može pripraviti širok spektar alkilnih i arilnih izotiocijanata. Osim klasiĉne organske sinteze p- nitrofenil-izotiocijanata i 1,4-diizotiocijanatobenzena provedena je i mikrovalovima potpomognuta sinteza pri razliĉitim snagama zraĉenja. Metode su usporeĊene s obzirom na njihovo trajanje i primijenjene reakcijske uvjete (temperatura, snaga mikrovalnog zraĉenja, korištene kemikalije, itd). Sintetizirani spojevi su potom identificirani uz pomoć kromatografskih i spektroskopskih tehnika. Dobiveni su odgovarajući podaci koji potvrĊuju strukture sintetiziranih produkata.Isothiocyanates (ITCs) are classified as a separate group of volatile sulfur compounds naturally occurring by enzymatic hydrolysis of glucosinolates in the presence of the myrosinase enzyme. Myrosinase causes cleavage of the thio-glucose bond to give rise to unstable aglycone. This aglycone spontaneously rearranges to several products. Most frequently, it undergoes a Lossen rearrangement to produce an isothiocyanates, at a neutral pH. Isothiocyanates have been reported as having important biological effects, particularly protection against chemical carcinogens and acting as major inhibitors of microbial and bacterial activity. Isothiocyanates have become interesting to many scientists in the past decade, and numerous methods of their synthesis have been developed. The aim of this study was preparation of p-nitrophenyl ITC with two different methods. The synthetic process involves an in situ generation of a dithiocarbamate salt from the amine substrate by reacting with CS 2 followed by elimination to form the isothiocyanate product with cyanuric acid as the desulfurylation reagent. This general and facile protocol is significant for the preparation of a broad range of alkyl and aryl isothiocyanates. In addition to the classic synthesis of p-nitrophenyl ITC and 1,4-diisothiocyanatobenzene, a microwave assisted synthesis was also performed at various radiation intensities. The methods were compared in terms of their duration and the reaction conditions. The synthesized compounds were identified with chromatographic and spectroscopic techniques. Analysi