Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Antimicrobial, Antioxidant, Antiproliferative and Cytotoxic Activities of Aronia Fruit Extract(01. Izmir Institute of Technology, 2023) Tanağardı, Dilaranur; Baysal, Ayşe Handan; Sezgin, EfeAronia melanocarpa contains high amounts of phenolic compounds, especially anthocyanins. Because of its high chemical content and significant antioxidant action, this food is known as a functional food, and its use is spreading worldwide. Within the scope of this thesis research, studies were carried out on Aronia melanocarpa dry extract and liquid extract. For these purposes, chromatographic and chemical profile were determined in detail by HPLC (High-Pressure Liquid Chromatography), Fourier-Transform Infrared Spectroscopy (FTIR) and Q-TOFF- MS (Quadrupole Time of Flight Mass Spectrometry), and significant bioactive were determined. Spectroscopic methods were used to characterize phenolic, anthocyanin, and flavonoid components. Aronia melanocarpa dry and liquid extracts were tested for antioxidant activity using DPPH and ABTS methods. The antioxidant potential of the Aronia melanocarpa dry and liquid extracts studied is high. To test the antiproliferative and cytotoxic effects, cytotoxic studies were performed on the CaCo2 cell line. Cell migration was also studied in HUVEC and HaCat cell lines. The antimicrobial activity of Aronia melanocarpa dry extract and liquid extract was tested against Saccharomyces cerevisiae, a yeast species, and bacterial strains of Staphylococcus aureus, Escherichia coli O157:H7, Salmonella Typhimurium. The extracts analyzed showed an antimicrobial effect on the tested bacteria at different concentrations. The results obtained in this study emphasize that the tested Aronia melanocarpa dry extract and liquid extract have antimicrobial properties. Chromatographic, chemical, and cytological data reveal that Aronia melanocarpa liquid and dry extracts can be used as antioxidative and antiproliferative products as food supplements in the health field.Master Thesis Bilayer Chitosan/Zein Based Nanofibers for Antimicrobial Wound Dressing Application(01. Izmir Institute of Technology, 2021) İskeçman, Nilsu; Tıhmınlıoğlu, FundaNowadays, modern functional wound dressings have become prominence due to their biocompatible, biodegradable, and non-toxic nature and ability to mimic ECM of skin. To enhance their mechanical and prolonged cumulative release of drugs in media, environmentally friendly inorganic nanofillers are preferred. Recently, halloysite nanotubes (HNTs) which is a new class of inorganic filler are using to improve mechanical properties and thanks to their tubular structure various agents encapsulated into these tubes to make drug release more controlled. In this thesis, it was aimed to fabricate and characterize bilayer wound dressing by using Zein-Vancomycin loaded HNTs nanofibers as upper layer to mimic ECM of skin and provide antibacterial protection and chitosan sponge as bottom layer to absorb the excess exudates of wound, provide gas transmission and facilitate the migration of inflammatory and fibroblast cells into the healing wounds. The morphology of nanofibers and encapsulation efficiency of HNTs are optimized to achieve similar homogeneous fiber structure with skin tissue and controlled release of Vancomycin drug. Chemical interaction between Vancomycin-HNT and Zein-HNT were characterized by FT-IR. The surface charge differences of HNTs by encapsulating drug into tubes was determined by zeta potential analysis. The weight loss percentage of nanofiber with the addition of HNTs into zein media was characterized by using thermogravimetric analysis (TGA). Bilayer sponges were characterized by SEM, FT-IR, porosity, mechanical properties, contact angle, water vapor transmission rate, swelling, degradation, cumulative drug release and their kinetics and antimicrobial activity analyzes. The diameter of drug loaded HNT-Zein nanofibers were found 202,7±0,05–225,2±0,06 nm which is in the range of native skin collagen fibril (50-500 nm) than can mimic ECM. The water vapor permeability of the wound dressings is between 2833 and 2490 g/m2day which is found in the appropriate range for wound healing. Bilayer dressings reached 78% cumulative release at the end of 14 days and the release medium showed antimicrobial activity against E. coli and for S. epidermidis. In conclusion, the developed drug-loaded bilayer mat has been found as a potential candidate for wound dressings applications to treat the chronic infections.Master Thesis Development of a Novel Active Packaging System Based on Layer-Sy Layer Deposition of Natural Antioxidants and Antimicrobials To Extend Food Products' Shelf Life(Izmir Institute of Technology, 2017) Akgün, Begüm; Korel, FigenIn recent years, Layer-by-Layer (LbL) assembly of thin films has been extensively investigated for many purposes, particularly for its functionality and simplicity of fabrication. Through LbL assembly; antioxidant agents have beenincorporated into active packaging systems in different forms, mainly including sachets, physical adsorption on packaging material surface, multilayer films which contact with food packaging surface. In previous studies, active packaging systen associated with LbL depositions were investigated, but no detailed investigation has been found about the application of controlled releasing-active packaging system on fresh-cut fruits. In this study, 20 bilayers of chitosan and alginate; respectively; were coated on amorphous polyethylene terephthalate (A-PET) sheets by dipping method. The LbL treated PET films were used for active packaging of fresh-cut peaches. Total soluble solids content and titrable acidity demonstrated that LbL active coating did not interfere with the natural postharvest behaviour. A lower weight loss was observed for LbL coated peach saples, suggesting that the presence of layer structure on PET strips could act as a barrier against fruit water loos. After 7 days of storage, the LbL treated samples have shown the best preservation of carotenoids, the lower PPO activity and higher phenolic index. Microbiological analysis has shown that all the microbiological analysis has that all the microorganism types which were invetigated were affected by the actice packaging system.Sensory results were really encouraging, as well. As a conclusion, LbL coating has been proved for being a useful technique to produce controlled-release active packaging systems on fresh-cut fruits.