Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Investigation of Antimicrobial, Antioxidant and Cytotoxic Properties of Some Green Leaf Plants(2023) Çetin, Elif Nur; Baysal, Ayşe Handan; Özen, Fatma BanuThe present study aims to investigate the chemical composition, antimicrobial activity, antioxidant properties, and cytotoxic activity of extracts obtained from leaf samples that are discarded as waste products. For this purpose, two different green leaves were selected: one is the grape (Vitis vinifera) leaf, a by-product from the winemaking process, and the other is the cauliflower (Brassica oleracea, var. botrytis) leaf, which is a waste product of cauliflower, and they were subjected to related tests. Both leaf samples were extracted by water because of its easy accessibility and environmentally friendly properties. Leaf extracts were examined according to their total phenolic content and subjected to chemical characterization by Liquid chromatography-quadrupole time-of-flight tandem mass spectrometry system. The promising antioxidant activities of the water-extracted leaf samples were authenticated through DPPH and ABTS assays. Antimicrobial and antibiofilm activities were examined against some Gram-positive (Bacillus cereus, Listeria innocua, and Carnobacterium divergens) and Gram-negative (Escherichia coli, Serratia liquefaciens, and Salmonella Typhimurium) strains, and two fungi (Saccharomyces cerevisiae and Candida albicans) species. Both tested leaf extracts showed a dose-dependent antimicrobial activity, while the antimicrobial activity of grape leaf extract was slightly higher. However, their activities against biofilm formation were varying in different bacterial and fungi species. The cytotoxic activity of the leaf extracts was examined on the mouse fibroblast cell (L929) line. According to the presented results, neither of the leaf extract samples used in the study showed any unwholesome effects on the cell line at any time point.Master Thesis Uv-C Irradiation and Lantibiotic Nisin Applications for Food Biopreservation(01. Izmir Institute of Technology, 2023) Altundaş, İlker; Baysal, Ayşe Handan; Sezgin, EfeThe antibacterial and antifungal activity of Lantibiotic Nisin and Essential oil Carvacrol against pathogenic and spoilage-forming microorganisms was investigated in this study. The antimicrobial activities of these compounds were observed in vitro on one Gram-positive (Listeria monocytogenes), two Gram-negative (Cronobacter sakazakii andS. Typhimurium) bacterial strains, and one fungus (Candida albicans). The study investigated the effect of combined treatments involving UV-C irradiation along with Nisin and carvacrol as antimicrobial agents on microbial growth, both at 4°C refrigerator temperature storage for two weeks, and on artificially inoculated chicken drumsticks with L. monocytogenes and S. Typhimurium. Total Aerobic Mesophilic, Yeast & Mold, and Enterobacter/Coliform populations were examined using plate counting on PCA, PDA, and VRBA media, for L. monocytogenes, and S. Typhimurium. PALCAM, OXFORD, and Bismuth Sulphite Agar, respectivelyMaster 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 Investigation of Probiotic Properties of Cold Brewed and Fermented Cold Coffee Beverage(01. Izmir Institute of Technology, 2023) Semiz, Şevval; Baysal, Ayşe HandanThe goal of the project was to produce a functional probiotic fermented cold brewed coffee that is perapered with medium roasted, grinded Colombian Arabica beans with patented probiotic yeast Saccharomyces boulardii that can survive in human gastrointestinal conditions. With pasteurization of the product, safe fermentation environment and long shelf life was achieved. Coffee brew samples were prepared with different techniques to understand the effects of fermentation and glucose fortification to fermentation media on coffee chemistry, microbiota and sensory characteristic. One of the three coffee brews was only pasteurized (P), one of them fermented (F) and the other was fermented with glucose (FG). The cold brewing and fermentation were performed respectively at 22 °C and 30 °C for 24 hours. The brewed samples were pasteurized before fermentation at 65 °C for 30 minutes. Each sample was examined during their 120 days shelf life (at +4 °C). Although the probiotic yeast enabled fermentation in coffee, it did not survive after the first week. Pasteurization was successful, so pathogen growth was not detected in any of the samples during their shelf life. While FG was evaluated as undrinkable, the other samples gave positive results in terms of sensory. Caffeine, chlorogenic acid, and ethanol levels were significantly altered during shelf life. This is the first study in which chemical, microbiological and sensory analyzes of cold coffee that was brewed via cold immersion method, pasteurized and fermented with patented S. boulardii yeast during shelf-life were conducted, and will lead to new studies in this field.Master Thesis Dynamics and Bioinformatis of Microbial Spoilage Ecology of Kefir(Izmir Institute of Technology, 2022) Memon, Ayşe; Baysal, Ayşe Handan; Sezgin, EfeIn this study, it was aimed to characterize the microbiological properties, bacterial composition, and microbial stability of 5 different commercial milk kefir beverage products during refrigerated storage. In order to determine the microbiological load and compositions, total mesophilic aerobic bacteria, yeast and molds, lactic acid bacteria, Lactobacilli, Lactococci, total coliforms, and E.coli were investigated by cultural conventional analysis for milk kefir beverages. According to the obtained data, microbiological and hygienic characteristics of the samples were found acceptable. The bacterial load of the kefir beverage samples ranged between 7.086 and 8.794 log10 cfu.ml-1 for viable total aerobic mesophilic bacteria (TAMB), 6.792 and 8.382 og10 cfu.ml-1 for lactic bacteria (LAB), <10 and 6.322 log10 cfu.ml-1for Lactobacillus, 5.857 and 8.146 log10 cfu.ml-1 Lactococcus, 5.176 and 7.218 log10 cfu.ml-1 for yeasts, negative for molds, coliform bacteria and negative for E. coli. Principal component analysis (PCA) of the compounds separated the kefir beverages according to the storage time and kefir brands. Strong relationship were found between storage time and PC1 and between kefir brands and PC2. To date, information on microbial properties, bacterial composition, and constancy of commercial kefir is scant, and to the best of our knowledge, this is the first research to contribute information on kefir beverages in microbial properties, bacterial composition, and their stability during refrigerated storage by evaluating Fourier Transform Infrared Spectroscopy (FTIR) spectra analysis and Bioinformatics besides cultural conventional analysis.Master Thesis Environmental Factors Influencing Bacterial Biofilm Formation and Inactivation(Izmir Institute of Technology, 2020) Üreğen, Mert; Baysal, Ayşe Handan; Özçivici, EnginObjective of this study was to evaluate effect of UV-C radiation (0, 1.16 and 3.21 kJ/cm2), pomegranate (Punica granatum) seed essential oil (PGEO) and lemon (Citrus lemonum) plant essential oil (CLEO) on decontamination of Candida albicans, Listeria monocytogenes, Staphylococcus aureus and Esherichia coli O157:H7 biofilms formed at +4°C and 20°C on polystyrene, stainless steel and glass surfaces. After 16, 32 and 64 sec UV-C treatment 0.24 log CFU/cm2, 1.61 log CFU/cm2, 1.59 log CFU/cm2 reductions were achieved in the numbers of C. albicans biofilms formed at 20°C on polystyrene. In the numbers of S. aureus biofilms formed at 20°C on polystyrene 0.99 log CFU/cm2, 1.9 log CFU/cm2, 3.91 log CFU/cm2 reductions were obtained after 16, 32 and 64 sec UV-C treatments, respectively. In general C. albicans biofilm formed at 20°C on stainless steel was found as the most UV-C resistant biofilm. CLEO inhibited the growth of C. albicans, L. monocytogenes and S. aureus at MIC values of 186 µg/ml, 103.5 µg/ml and 103.5 µg/ml, respectively. The results of the study showed that UV-C radiation and CLEO can be used as an anti-biofilm agent to control or to prevent biofilm formation of foodborne bacterial pathogens. It was suggested that UV-C radiation and CLEO treatments have potential as a biofilm control interventions for the food industry.Master Thesis Developing Probiotic Lozenges To Improve Oral Health(Izmir Institute of Technology, 2019) Elvan, Menşure; Harsa, Hayriye Şebnem; Baysal, Ayşe HandanRecently, there is a great need to overcome complaints about oral health from children, mental and physically handicapped people who are inadequate in oral hygiene and after chemotherapy of cancer patients. With reduced body resistance, opportunistic Streptococcus mutans and Candida albicans in the mouth become dominant, causing disruption of oral health. Therefore, the effect of lactic acid bacteria on pathogens was investigated in order to protect oral health with the thesis study. Lactobacillus pentosus NRRL-B 227 was determined among the probiotic bacteria tested for this purpose and its activity on the pathogen Streptoccocus mutans ATCC 25175 and Candida albicans DSMZ 5817 was found in broth microdilution, agar overlay and planktonic culture assays except disc diffusion test. To reduce the number of pathogens in oral microflora, lozenges containing L. pentosus were developed. Three different lozenges with encapsulated and free bacteria and control lozenge were produced, kept at different temperatures; 4⁰C and 25⁰C. No significant decrease in viability of the encapsulated probiotic strain after lozenge production and storage at 4°C was observed, the probiotic amount in the lozenge initially counted as 7.84 log CFU/g, while 7.73 log CFU/g at the end of 3 months shelf life. However, lozenges stored at 25⁰C probiotics lost their vitality after one month. Additionally, lozenges containing free bacteria have lost viability rapidly. Color and water activity were observed differently in the formulations (p <0.05). The formulations maintained their microbiological safety during storage. Lozenge with L. pentosus NRRL-B 227 has a significant potential for improving oral health and provides an alternative to the diversification of products containing probiotics.Master Thesis Differentiation of Filamentous Fungi by Polymerase Chain Reaction (pcr) and Fourier Transform Infrared (ftir) Spectroscopy(Izmir Institute of Technology, 2017) Güngör, Sinem; Baysal, Ayşe HandanFourier transform infrared (FTIR) spectroscopy is considered to be a rapid, reliable, sensitive, and a cost-effective technique, which could be used as an efficient tool for microorganism identification. Since bio-molecules, such as lipids, carbohydrates, and nucleic acids, have their own unique ‘vibrational’ fingerprints and characteristic functional groups, which correspond to specific infrared light frequencies, FTIR spectrum obtained for any compound gives the information on the unique ‘fingerprint’. The objective of this study was to investigate the ability of FTIR spectroscopy for differentiating different species of filamentous fungi. In this study, Erkence cultivar olives which were collected from different orchards were used for different fungal strain isolation. The fungi isolates were grown on Malt Extract Agar (MEA) and Czapek Yeast Agar (CYA) at room temperature of 25ºC for 10 days. 15 different genera and 53 species were identified by using Polymerase Chain Reaction (PCR) and characterized in terms of DNA sequencing. FTIR spectroscopy was applied to 71 species as a novel technique to identify fungi. 18 pre-defined species that were collected fom previous studies, were also used for FTIR spectroscopy investigation. Statistical analysis of the data was performed by using a principal component analysis (PCA). FTIR spectroscopy provides a potentially powerful approach to differentiate filamentous fungi.Master Thesis Real-Time Pcr as a Molecular Tool for the Enumeration of Probiotics in Commercial Products(Izmir Institute of Technology, 2016) Öz, Ödül; Baysal, Ayşe Handan; Arslanoğlu, AlperQuantitative Real-Time PCR (qPCR) assays targeting the 16S rDNA was developed as a genus and species specific detection tool for Bifidobacterium and Lactobacillus, and Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus acidophilus LA-5, respectively. Standard curves were established to quantify these probiotic bacteria. The linear regression of standard curves indicated high correlations between the log numbers of pure probiotic culture cells and the Ct values. The assay had a high efficiency and the limit of detection was estimated to be 1.54 ng DNA (corresponding to 104 cells). Results show that qPCR method may be very useful as a rapid, sensitive and specific tool for detecting and quantifying B. animalis subsp. lactis BB-12 and L. acidophilus LA-5 in probiotic supplements. FTIR spectroscopy was used for the first time to determine the ratios of different microorganisms in commercial probiotic supplements. FTIR analysis was also performed for the pure probiotic cultures of B. animalis subsp. lactis BB-12 and L. acidophilus LA-5. Results obtained in this study showed that FTIR spectroscopy is potentially a rapid method for determining probiotic cell components and their ratios in the supplements and verification their detection and identification.Master Thesis Microbiological Characterization of 'hurma Olives Grown in Karaburun Peninsula(Izmir Institute of Technology, 2013) Karslı, Gözde Seval; Baysal, Ayşe HandanErkence variety olive (Olea europea L.) cultivar growing in the Aegean Region of Turkey is a naturally black olive. Debittered Erkence variety called "Hurma" olive is an unusual olive type which is characterized by the sweet taste of its fruit. This olive which is grown mainly in Karaburun Peninsula differs from other varieties since it ripens on the tree losing its bitterness caused by phenolic compounds especially oleuropein. Thus, Hurma olives can be directly consumed from the tree without a further debittering process to make them edible. Total aerobic mesophilic microorganisms, lactic acid bacteria (LAB), Enterobacteriacaae, Pseudomonadaceae, Staphylococcaceae-Micrococcaceae, moulds and yeasts were enumerated in the olive drupes, leaves and orchards' air of Erkence and Gemlik cultivars during the maturation period. Moreover, bacterial microflora of Hurma olive fruit, leaf and orchards' air were characterized in terms of DNA sequencing. Microbial loads of naturally debittered "Hurma" olive were higher when compared with Gemlik olive's and non-debittered Erkence variety olive's. But no Pseudomonadaceae, Staphylococcaceae-Micrococcaceae and LAB were detected in all samples. Bacterial microflora genera of Hurma olive comprised of Bacillus, Pantoea, Acinetobacter and Pseudomonas while the other samples have also similar bacterial genera. The common genus found in all samples was Bacillus. Besides, more diversified genera were obtained from phylloplane and air microflora of Erkence variety olive orchard was substantially similar to bacterial phylloplane of leaf. This is the first study about microbiological characterization of Hurma olive type and will lead up to new studies about it.