Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Plant biotechnologyWoS Q: search.filters.wosQuartile.N/A

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Now showing 1 - 5 of 5
  • Master Thesis
    Investigation of Antimicrobial, Antioxidant and Cytotoxic Properties of Some Green Leaf Plants
    (2023) Çetin, Elif Nur; Baysal, Ayşe Handan; Özen, Fatma Banu
    The 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
    Characterization of Peppers for Antioxidant Content and Virus Resistance
    (Izmir Institute of Technology, 2008) Keçeli, Mehmet Ali; Doğanlar, Sami
    In the first part of this study, total water soluble antioxidant activity, phenolic compounds and vitamin C content of 29 Turkish and 14 non-Turkish pepper cultivars were determined. Significant trait diversity was found in the cultivars with the most variation (7.4-fold) seen for total antioxidant capacity which ranged from 2565 to 18957 .mol Trolox/kg. Vitamin C content for the peppers ranged from 522 to 1631 mg/kg, a 3.1-fold difference, while total phenolic content for the pepper cultivars ranged from 607 to 2724 mg/kg, a 4.5-fold difference. A strong correlation between total antioxidant capacity and phenolic content (r . 0.71) was also seen. Significant variation for antioxidant content in Turkish germplasm indicates that this material can be used for improvement and genetic mapping of nutritional content in pepper. In the second part of this study, amplified fragment length polymorphism (AFLP), cleaved amplified polymorphism (CAPs) and simple sequence repeat (SSR) markers were used to map gene(s) for cucumber mosaic virus resistance. The mapping was conducted using a F2 population derived from a cross between Capsicum annuum cv. Jupiter (susceptible) X C. frutescens (resistant). The F2 population, consisting of 76 individuals, was screened with 13 AFLP primer pairs, 60 CAPs markers and 30 SSR markers to detect markers possibly linked to CMV resistance gene(s). As a result, 7 QTL were found which are related with resistance to CMV in pepper. This will provide pepper breeders an opportunity to use these markers for marker-assisted selection for CMV resistance in pepper.
  • Master Thesis
    Encapsulation of Sarcopoterim Spinosum Extract in Zein Perticle by Using Electrospray Method
    (Izmir Institute of Technology, 2013) Süngüç, Ceren; Bayraktar, Oğuz
    Sarcopoterium spinosum species has valuable and common medicinal plant in the Mediterranean region. The optimum conditions for the extraction of S. spinosum leaves to obtain bioactive extract were investigated using response surface methodology (RSM). Total phenol contents, total antioxidant and antibacterial activities, phenolic composition of S. spinosum extract were studied. The prepared S. spinosum extract showed high antioxidant activity when compared with many other medicinal plants in the literature. It was determined as 3143.5 mmole Trolox per gr dry weight. The phenolic content of S. spinosum extract was examined with High Performance Liquid Chromatography (HPLC). Hyperoside and isoquercetin were detected in S. spinosum extract. Especially, isoquercetin was the major compound in the extract. In addition, the antimicrobial activity of S. spinosum extract was investigated. The extract showed fungicide activity against Candida albicans. S. spinosum extract were encapsulated within zein particle via electrospray method in order to enhance its stability. The effects of process parameters for electrospraying method on the particle morphology and size distribution were extensively investigated. The best process conditions were determined as zein concentration of 5% (w/v) in 70% aqueous ethanol solution, flow rate of 0.3 ml/h and applied voltage of 14 kV depending on narrow size distribution, spherical and smooth particle morphology. The best S. spinosum extract loading was achieved at extract to zein weight ratio of 1:5. The prepared extract loaded zein microparticles showed significant antioxidant activity.
  • Master Thesis
    Screening of Some Plant Species for Their Total Antioxidant and Antimicrobial Activities
    (Izmir Institute of Technology, 2008) Kaçar, Diren; Bayraktar, Oğuz
    In this study aqueous/ethanol extracts of 42 plant species collected from same geographic region (Karaburun/İzmir) were screened for their relative total phenol contents, total antioxidant and antibacterial activities. In the first part of the study, Folin- ciocalteu assay and PCL (Photochemiluminescence) method were performed to detect the total phenol contents and total antioxidant activities of extracts, respectively.It was detected that the Hypericum empetrifolium had the highest activities for both water soluble and lipid soluble antioxidants and Sarcopterium spinosum has the highest result for total phenol assay as 635.26 GAEqmg/g sample.In order to detect the antibacterial activities of extracts a preliminary screening study was performed by using disc diffusion method. Out of the 42 plant species tested, 26 species exhibited antibacterial activities by inhibiting one or more microorganisms.Microdilution assays by 96 well plates were applied for the most active species to find out their minimum inhibition concentrations (MICs). The most promising plant species in the study, having the antibacterial activities were determined as H. empetrifolium, P.terebinthus, Arbutus unedo, and C. parviflorus.In this study there is a clear relationship between the analysis results and S.spinosum is one of the most noteworthy species in this study showing the highest total phenol content and important biological activities which has never been examined scientifically before. In that manner this study also presents new potential species that can be used as natural raw materials in some related industries.
  • Master Thesis
    Antimicrobial and Antioxidant Activities of Olive Leafextract and Its Food Applications
    (Izmir Institute of Technology, 2010) Aytul, Kerem Kaan; Korel, Figen
    In this study, aqueous/ethanol extract of olive leaves (OLE) was examined for its antimicrobial and antioxidant activities and its possible food applications. In the first part of the study, relative antioxidant capacity and total phenol content of the extract were determined and found as 966 .g ascorbic acid eq./mg and 197.42 mg GAEq/g sample, respectively. In the second part, microdilution assays were conducted by 96 well plate for OLE to find minimum inhibition concentration (MIC) against Gram (+) and Gram (-) bacteria. The most susceptible bacteria were Escherichia coli, Listeria innocua and Staphylococcus carnosus. In the third part OLE was applied to raw beef cubes with 1%, 2% and 3% (v/w) concentrations to examine its antimicrobial and antioxidant effects. The results clearly indicated that usage of 2% and 3% OLE had the beneficial effect in controlling the microbial load, total viable and coliform counts, of beef cubes during 9 days of storage at 4 C. The 2% OLE treatment applied to beef cubes also delayed the oxidative deterioration compared to the other samples. As the last part of the study, 300 ppm OLE was applied to sardine (Sardina pilchardus) fillets as a marinade component. Results indicated that OLE was effective in controlling microbial load of sardine fillets and also delayed the oxidative deterioration and total volatile base nitrogen formation in the fillets during marination process.