Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Effect of Edible Film and Allicin on Shelf Life of Chicken Meat(01. Izmir Institute of Technology, 2024) Cancı, Şeyda; Baysal, Ayşe HandanTavuk eti besleyici değeri sebebiyle sağlıklı beslenme için önemli bir gıdadır ve büyüme çağındaki çocuklar ve yaşlılar gibi toplumun çoğu popülasyonu tarafından tüketilen bir gıdadır. Ancak tavuk eti kolay bozulabilen bir gıdadır ve bunun önüne geçmek için yenilebilir kaplamalardan ve biyoaktif bileşenlerden yararlanılmaktadır. Bu çalışmada, kitosanın antibakteriyel, antimikrobiyal, biyouyumlu ve biyolojik olarak parçalanabilir özellikleri ve allisinin antimikrobiyal, antifungal ve antioksidan özellikleri kullanılarak tavuk bagetlerdeki raf ömrüne etkisi incelenmiştir. Tavuk bagetlerin, farklı konsantrasyonlarda hazırlanan kitosan ve allisin çözeltileriyle K1A1(1% Kitosan + 10% Allisin), K1A2 (1% Kitosan + 20% Allisin), K2A1(2% Kitosan + 10% Allisin), K2A2(2% Kitosan + 20% Allisin) ve sadece kitosanın farklı konsantrasyonlarını içeren çözeltileriyle (%1 Kitosan, %2 Kitosan) kaplanması, mikrobiyolojik özellikleri, duyusal özellikleri, kimyasal parametleri, oksidatif bozulma parametreleri belirlenen raf ömrü boyunca 4 ⸰C'de saklanarak değerlendirilmiştir. Kitosan ve allisin ile kaplanan numunelerde ve kitosan çözeltisiyle kaplanmış numunelerde kontrol grubuna kıyasla toplam canlı, Enterobacteriaceae, Pseudomonas bakteri sayımlarında, bakteri sayısı önemli ölçüde azalmıştır. Toplam canlı gelişimini engellemede en etkili sonuç, tavuk bagetlerin raf ömrünü uzatan K2A1 örnek grubuyla elde edildi. Depolamanın 10. günündeki TBA sonuçlarında, %1 kitosanla kaplanmış tavuk bagetlerin 0.33 mg MDA/kg değeriyle lipid oksidasyonunu engellemede en başarılı grup olduğu bulunmuştur. Bu sonuçtan sonra en başarılı sonuç 0.55 mg MDA/kg değeriyle K1A2 örneği olmuştur. Anahtar Kelimeler: Allisin, Antimikrobiyal,Antioksidan, Kitosan, TBA, Toplam canlıMaster Thesis Adsorbent Synthesis for the Recovery of Lithium Water Resources(01. Izmir Institute of Technology, 2022) Kahvecioğlu, Anıl; Yüksel Özşen, Aslı; Yüksel Özşen, AslıLithium is a crucial mineral for the 21st century due to its utilization in a wide range of industries. Lithium demand will increase because of car battery developments and the necessity for power storage. Investigating alternative strategies for resource recovery is the only way to fulfill this unexpected rise properly and sustainably in demand. Adsorption has been discovered to have some technological advantages over other methods. It is considerably less expensive, lacks the chemical resistance present in membranes, lacks the significant electrical demand of electrochemical approaches, as well as the restricted selectivity and challenges in integration into commercial processes. Lithium manganese oxides, also known as lithium ion-sieves, are adsorbents for lithium extraction that have remarkably high selectivity, high adsorption capacity, minimal toxicity, good chemical stability and cheap cost. They are one of the most promising inorganic adsorbents. This research emphasized on the recovery of lithium from water resources through the use of lithium manganese oxide, which were synthesized in laboratory. They were transformed into spherical beads by adding chitosan, followed by crosslinking these beads with epichlorohydrin to increase their adsorption yield, stability, and reusability. Characterization techniques such as SEM, XRD and BET were applied on the adsorbents. Results shows that the adsorbents distributed uniformly, the adsorbent powder was mesoporous, and from the adsorption studies it was found that the adsorbent worked much better in alkaline conditions such as pH 12, optimum adsorbent dosage estimated as 4 g/L and the equilibrium time measured as 10 hours. From the desorption study approximately 95% of Li desorbed for the first cycle, after the second cycle the adsorbent efficiency started to decrease.Master Thesis Surface Modification of Chitosan Films/Meshes for Biomaterial Applications(Izmir Institute of Technology, 2019) Işıklı, Berçin; Tıhmınlıoğlu, FundaModification of surface of biomaterials is a great interest for many years due to first contact of surface of materials with the biological fluids. This thesis aims to investigate surface modification effect on the chemical, surface wettability, protein adsorption as well biodegradability properties of dense chitosan (Ch) and asymmetric chitosan films (ACh). The surfaces of chitosan dense and asymmetric films were modified by ion implantation technique using carbon and carbon-nitrogen hybrid ions at a fluence of 1x1015 ions/cm2 and ion energy of 20kV. Chemical compositions of the film surfaces were analyzed by Fourier transform infrared spectroscopy (FTIR-ATR). Surface hydrophobicity measurements were conducted by static contact angle measurements. Protein adsorption on unmodified and modified surfaces on films was investigated as a function of time at various pH conditions. After ion implantation on chitosan films, both C and C-Nitrogen ion implantation, the surfaces become rougher and hydrophobic having moderate wettability (����� values in the range of 72-85°) and in good agreement with FTIR-ATR data findings. It was found pH dependence of the amount of protein adsorbed on the dense chitosan films as a function of time for both un-implanted and implanted films. BSA and fibrinogen were more adsorbed on the chitosan films at pH 5. The amount of BSA and fibrinogen protein adsorption was 0.97 and 1.33 gprotein/gfilm, respectively for 60 min incubation period. Protein adsorption enhanced for C and C+N2 ion implanted samples for BSA and fibrinogen, respectively due to the hydrophobic protein surface interaction effect. In vitro degradation results showed that ACh films degrade much faster (mass loss 57 %) than Ch films (40 %) due to the porous structure at the end of 3 weeks. However, the ion implanted Ch samples degraded much slower having mass loss of 30% and 17.7% for C+N2 and C implanted samples, respectively at the end of 3 weeks compared to un-implanted Ch films as 40 %. The results are in good agreement with water sorption and surface hydrophobicity of the implanted films. This study demonstrated that surface modification, as well as structure, changes the protein sorption, wettability and biodegradation properties of the chitosan films.Master Thesis Preparation and Characterization of Polymer Based Composite Nanospheres for Bone Infection Prevention(Izmir Institute of Technology, 2018) Kımna, Ceren; Tıhmınlıoğlu, FundaCurrently, bone tissue engineering applications comprise the development of smart materials that can induce tissue regeneration meanwhile supporting the defect site of the body. Despite of the advancements, inflammation is still a serious problem that threatens human health at the post-implantation period. To overcome potential inflammations, antibiotic therapy is commonly employed in clinical trials. However, antibiotic therapy causes some side effects such as ototoxicity and nephrotoxicity, especially when applied in high doses. Therefore, local drug delivery systems play a vital role in bone disorders due to the elimination of disadvantages introduced by conventional methods. In the presented study, it was aimed to develop chitosan-based composite nanospheres as a controlled drug delivery system against bone infections. Accordingly, chitosan and montmorillonite nanoclay was homogenized with microfluidizer and electrosprayed to obtain spherical nanoparticles. The optimum electrospraying conditions were investigated using response surface methodology. Vancomycin and Gentamicin antibiotics were incorporated in the polymeric matrix to provide controlled release at the defect region to overcome inflammations after implantation. The prepared nanospheres were characterized in terms of morphology, hydrodynamic size distribution, surface charge, drug encapsulation efficiency and release profiles. The dominant drug release mechanism was determined by empirical mathematic models. Drug loaded nanospheres have been successfully produced with a size range of 180-350 nm. High encapsulation efficiency was achieved (80-95%) with a controlled drug release up to 30 days. Fickian diffusion was found as the main mechanism in drug delivery from spherical CS/MMT nanocomposites. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to 3T3 and SaOS-2 cell lines. These results demonstrated that the prepared nanospheres can be a promising option for bone infection prevention.Master Thesis Design of Micelle Embedded Chitosan Nanocomposites for Targeted Delivery of Hydrophobic Drugs(Izmir Institute of Technology, 2016) Cihan, Esra; Polat, HürriyetWhen successed to synthesize in a nanoparticulate form, chitosan has found to be a very effective biomaterial for drug delivery purposes owing to its extremely attractive characteristics such as its positive charge and pH sensitivity in aqueous medium. However, its structure as it is, is not suitable for oil soluble drugs. Even a close control on the size and shape of chitosan particles alone becomes a state of art and the production of chitosan nanoparticles is very difficult. Therefore, in this study, several methods were designed and used for synthesis of chitosan nanoparticles (<100 nm) with a hydrophobic core that are suitable for oil soluble drugs. Characterization of these nanoparticles were done by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Scanning Transmission Microscope (STEM), Transmission Electron Microscope (TEM), surface tension and zeta potential measurements. It was concluded that the best method was the coupling of drug loading with simple ionic gelation method among all the others. Hydrophobic drug loaded micelle embedded chitosan nano particles were able to manufactured successfully. The sizes of chitosan particles that embed Pluronic-123 micelles were larger (<100 nm) than the sizes of Pluronic-123 micelles (20 nm) alone. It was also possible to obtain smaller chitosan nanoparticles (<50 nm) that embed drug loaded Pluronic-123 micelles when their structure is modified by Sodiumdodecylsulfate.Master Thesis Chitosan-Plasmid Dna Nanoparticles: Cytotoxic and Cytostatic Effects on Human Cell Lines(Izmir Institute of Technology, 2015) Bor, Gizem; Şanlı Mohamed, Gülşah; Demir, Mustafa MuammerAlthough chitosan nanoparticles (CNs) became a promising tool for several biological and medical applications owing to their inherent biocompatibility and biodegrability, studies regarding their effects on cytotoxicity and cytostatic properties still remain insufficient. Therefore, in the present study, we decided to perform comprehensive analysis of the interactions between CNs – pKindling-Red-Mito (pDNA) and different cell line models derived from blood system and human solid tissues cancers. The resulting CNs-pDNA was investigated with regard to their physical-chemical properties, cellular uptake and transfection efficiency, cytotoxic and cytostatic properties. The nanoparticles showed high encapsulation efficiency and physical stability even after 2 days for various formulations. Moreover, high gene expression levels were observed already 96 h after transfection. CNs-pDNA treatment, despite the absence of oxidative stress induction, caused cell cycle arrest in G0/G1 phase and as consequence led to premature senescence, which turned out to be both, p21-dependent and p21-independent. Also, observed DNMT2 upregulation may suggest the activation of different pathways protecting from the resulting CNs-mediated stress. In conclusion, treatment of different cell lines with CNs-pDNA showed that their biocompatibility was limited and effects were cell type-dependent.Master Thesis Development of a Hybrid Sorbent Composed of Natural Materials for the Removal of Arsenic From Waters(Izmir Institute of Technology, 2014) Yılmaz, Dilek; Sofuoğlu, Sait CemilA novel sorbent has been developed by immobilizing chitosan onto pumice for As(V) sorption from waters. In order to ensure its functionality, sorption performance was determined by measuring As concentrations in water using hydride generation atomic absorption spectrometry. The success of the immobilization was checked with characterization techniques as scanning electron microscopy, thermal gravimetric analysis, and elemental analysis. Points of zero charges were determined with potentiometric mass titration. Batch type equilibration studies showed that the sorbent can be employed at a wide pH range resulting in quantitative sorption (>90%) at pH 3.0-7.0, and greater than 70% sorption at pH>8.0. These results demonstrate the advantage of immobilizing chitosan onto pumice, because, under the same conditions, pumice displays <20% sorption towards As(V) whereas chitosan gives approximately 90% sorption but only at pH 3.0. The validity of the method was verified through the analysis of ultra-pure, bottled drinking, and tap water samples spiked with arsenate; the respective sorption percentages of 93.2 (±0.7), 89.0 (±1.0), and 80.9 (±1.3) were obtained by batch type equilibration. The sorbent was applied in a column for the spiked samples of ultra-pure and tap water. Similar sorption percentages (60% at the 18th fraction) were obtained for ultra-pure water whereas the methodology gave more efficient results for tap water (90% at the 20th fraction) demonstrating the potential of the sorbent for an efficient water treatment system. Arsenic sorption was also examined in the presence of common interfering ions resulting in competing effects of PO43- and NO3- on As(V) adsorption.Master Thesis Development of Whey Protein Isolate Based Nanocomposite Food Packaging Film Incorporated With Chitosan and Zein Nanoparticles(Izmir Institute of Technology, 2014) Oymacı, Pelin; Alsoy Altınkaya, Sacide; Demir, Mustafa MuammerThe purpose of this study was to investigate the effect of chitosan and zein nanoparticles addition on the barrier and mechanical properties of whey protein isolate (WPI) films as an alternative to conventional synthetic packaging materials. Chitosan nanoparticles (CSNP) were produced via ionic gelation method using sodium tripolyphosphate (TPP) and deacetylated chitosan. Zein nanoparticles (ZNP) were synthesized based on antisolvent procedure in the presence of sodium caseinate (SC) to enable dispersion in water. Both plain and nanoparticle added WPI films were prepared by solution casting method. Water vapor barrier and mechanical properties of films were measured and the improvements in these properties with nanoparticle addition was further investigated through surface wetting, morphological, viscoelastic and thermal properties of the films. Both nanoparticles significantly decreased the water vapor permeability (WVP) and improved the mechanical properties of the WPI film. The highest enhancement in barrier and mechanical properties of the WPI films were recorded with 20% (w/w of WPI) CSNP and 120% (w/w of WPI) ZNP addition which corresponded to the maximum nanoparticle loading levels. At these loadings, the average WVP of pure WPI films loaded with ZNP and CSNP decreased by 84% and 57%, and the average tensile strength increased by 304% and 161%, respectively. On the other hand, the nanoparticles did not change the elongation at break significantly. ZNP was found more effective than CSNP in improving barrier and mechanical properties of the WPI films due to its hydrophobic nature and better dispersion in the protein matrix which allowed much higher loadings compared with the maximum loading levels achieved with CSNP. CSNP addition imparted antibacterial activity to the WPI films.Master Thesis The Effect of Surface Modification of Biomaterials on the Cellular Interactions(Izmir Institute of Technology, 2008) Özgür, Melek; Çiftçioğlu, MuhsinThe preparation and characterization of chitosan-hydroxyapatite composite scaffolds and protein adsorption chracteristics of these scaffolds have been investigated in this study. The effects of different chitosan/hydroxyapatite contents of the low density composites on the protein adsorption behaviour were experimentally examined.Bradford method at 595 nm and 280 nm UV protein absorption methods were used for the determination of adsorbed amount of bovine serum albumin (BSA) and human serum protein (HSP). In this study low molecular weight chitosan and hydroxyapatite have been used for the preparation of the scaffold composites by freeze drying and SEM was used for microstructural analysis. The thermal behaviour of the composites was investigated by DSC and TGA. Composite scaffolds were prepared by using different amounts of chitosan and hydroxyapatite (HA) and six different scaffolds were prepared and coded as C100H0, C80H20, C70H30, C50H50, C30H70, and C20H80. The porous low density scaffolds had 93.5-96.3% porosity with a slight increase in density with increasing HA content. The interconnected pore network was formed from 50-250 .m relatively uniform size pores with thin pore walls. The HA particles were fully embedded in the polymer matrix in the pore walls. The TGA curves have shown that the freeze dried phase seperation induced biopolymer sturucture degrates at lower temperatures faster than the original raw polymer. The adsorptions of BSA and HSP onto composites have been studied as a function of time, protein concentration and pH. Adsorption experiments were also conducted with commercial HA powder. The adsorption kinetics experiments have indicated that protein adsorption was almost completely achieved in the first 2-3 hours with relatively high uptake values of up to 45-60 mg/g and 40-60 mg/g for 595 nm Bradford and 280 nm methods. The adsorption behaviour did not fit to the commonly known Langmuir and Freundlich isotherms. This was attributed to the swelling/degradation tendency of the freeze-dried chitosan containing scaffolds. The HSP uptake of 30 and 50 wt% HA containing composites were in the 50-60 mg/g range which was higher than other composites and the raw unprocessed chitosan.Master Thesis Production and Isolation of Fungal Chitosan by Submerged Fermentation(Izmir Institute of Technology, 2003) Alper, Seda; Harsa, Hayriye ŞebnemChitosan is the N-deacetylated derivative of chitin which is the supporting material of crustaceans and insects. Chitosan together with chitin are recommended as suitable functional materials because of their excellent biocompatibility, biodegradability, non-toxicity and adsorption properties and can be used in agriculture, biotechnology and food industry. Although chitosan is produced by chemical deacetylation of chitin molecule, it is also a natural component of cell walls of fungi belonging to Zygomycetes and can be produced by extraction from fungus cell walls. Fungi are thus the promising alternative sources of chitosan. Fungi can be manipulated to give chitosan of more consistent and desired physico-chemical properties compared to chitosan obtained from crustacean sources. In this study, Absidia spp, Aspergillus niger, Rhizopus arrhizus, Cunnighamella elegans, and Mucor rouxii were examined for biomass growth. At first, all five species were grown on synthetic medium at 28 C, 180 rpm in shake-flask incubator. Mucorrouxii which gave the maximum biomass concentration was also grown on molasses. The maximum biomass concentration of Mucor rouxii was found to be higher than that of synthetic medium. The best growth conditions obtained were 4% sucrose, 0.2% yeast extract, 1% peptone and 106 spores in 40 ml. The mycelia harvested at late exponential phase was treated with alkali to remove proteins and chitosan was extracted from cell wall by using acetic acid. The yield of extractable chitosan obtained from cell wall of Mucor rouxii was 2500 mg / l and it is almost 20 % of biomass and approximately 35 % of alkali insoluble fraction.