Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Development of Biosensors for Determination of the Total Antioxidant Capacity(Izmir Institute of Technology, 2008) Çoban, Seçil; Bayraktar, OğuzIn this study, an amperometric laccase biosensor was developed for determination of the oleuropein concentration that is the biological active component of olive leaf and contributes dominantly to the total antioxidant capacity. The biosensor was prepared by immobilization of laccase from Trametes versicolor by addition of cross-linking agent, glutaraldehyde, into the carbon paste electrode. Different biosensors were prepared by changing the amount of crosslinking agent and concentration of the enzyme solution. So, effect of these parameters on biosensor performance was investigated. The best biosensor performance was determined for the biosensor having glutaraldehyde amount of 12.03 % vol. of the biosensor bottom part and 5 mg/ml of laccase enzyme. The effect of scan rate and temperature on the biosensor performance was also investigated in this study. The scan rate of 10 mV/s was decided to be the optimum for the amperometric detection of oleuropein considering the fastest response and maximum reduction current. 250C was chosen as an optimum temperature value due to the maximum laccase activity and capability of oleuropein acting as an antioxidant. Extraction of phenolics from olive leaf was also an important part of this study. The extract was divided into fractions varying in their oleuropein amounts such as polar fractions and relatively less polar fractions. Therefore, biosensor performance was investigated for fractions containing different type of phenolics. HPLC analyses of the fractions were also performed in this study. In addition total phenol content and antioxidant capacity of the fractions were determined by conventional methods.Master Thesis Determination of Genetic Diversity and Antioxidant Content of the National Melon (cucumis Melo) Collection(Izmir Institute of Technology, 2008) Şığva, Hasan Özgür; Frary, Anne; Frary, AnneIn this study, characterization with 19 morphological criteria and two types of PCRbased molecular marker systems, Simple Sequence Repeats (SSRs, microsatellites) and Amplified Fragment Length Polymorphisims (AFLPs), were used to characterize genetic variability among 238 national melon (Cucumis melo L.) accessions and 12 different members of the Cucurbitaceae family.According to morphological analysis, all accessions were vigourous. The accessions showed a great variety of fruit shape, 53 (38.4%) accessions were globular (round), 51 (37.0%) were eliptical, 15 (10.9%) were ovate, 7 (5.1%) oblate, 2 (1.4%) elongate and one accession was flattened. Another agronomically important criterion was predominant fruit skin colour. A total of 55 (39.9%) accessions had light yellow predominant skin colour, 34 (24.6%) were pale green, 29 (21.0%) were orange, 9 (6.5%) were cream, 6 (4.4%) were green, 4 (2.9%) were blackish-green and 1 (0.7%) was dark green.In accordance with genetic characterization, a total of 345 polymorphic AFLP fragments (products of 10 AFLP primer combinations) and 93 SSR fragments (products of 12 SSR markers) were detected and used to calculate genetic distance using DICE matrix and UPGMA (Unweighted Pair Group Method) arithmetical averages. The average polymorphic AFLP fragments per combination was 34.5 and SSR fragments per marker was 7.75. The phylogenetic tree showed that groups were clearly separated by both marker systems. This study allowed the identification of the relationship between national melon accessions based on genetic similarity or differences.Forty three melon accessions were also analyzed for total water soluble antioxidant and total phenolic compound activities.Master Thesis Characterization of Antioxdant Activity and Protein Functionality in Some Legume Cultivars Grown in Turkey(Izmir Institute of Technology, 2008) Aydemir, Levent Yurdaer; Yemenicioğlu, AhmetTurkish chickpeas (4 cultivars) and lentils (6 cultivars) show similar total phenolic contents and free radical scavenging capacities in aqueous extracts ranging between 2869 and 4312 mg gallic acid equivalents/kg legume and 24.42 and 38.20 mmol Trolox equivalents/kg legume, respectively. However, the free radical scavenging capacity of lentil and chickpea protein extracts, range between 110 and 185 mmol Trolox/kg protein and 58 and 144 mmol Trolox/kg protein, respectively, clearly showed the higher free radical scavenging capacity of lentil proteins than chickpea proteins.Protein extracts of chickpeas and lentils showed considerable emulsifying and foaming capacities in almost at the same range, but emulsions and foams formed by chickpea proteins are more stable than those of lentil proteins. The lentil protein extracts are highly soluble and showed poor water absorption and gelling characteristics. In contrast, chickpea protein extracts showed moderate water absorption and gelling capacity.Chickpea protein extracts are also good oil absorbers with almost 1.5 to 2 fold better oil adsorption capacity than lentil protein extracts. Thus, chickpea proteins are suggested as soy and whey protein alternatives for functional proteins used in the food, drug and cosmetics industries. Considering functional properties of proteins for different cultivars, the outstanding Turkish chickpea cultivars are Gökçe and Cevdetbey, while the outstanding Turkish lentil cultivar is Alidayı. Variations in the functional properties of protein suggest the diversity of genes in chickpeas and lentils responsible for these properties. Thus, this study showed the possibility of improving functional properties of chickpeas and lentils by breeding programs.Master Thesis Characterization of Peppers for Antioxidant Content and Virus Resistance(Izmir Institute of Technology, 2008) Keçeli, Mehmet Ali; Doğanlar, SamiIn 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 Production of Proanthocyanidins From Grape Seed(Izmir Institute of Technology, 2003) Altıok, Evren; Ülkü, Semra; Ülkü, SemraProanthocyanidin is a potent antioxidant that is why it directly affects many important diseases such as coronary heart disease, cholesterol etc. Thus, proanthocyanidin is one of the important dietary supplements, which is mainly found in grape seeds. In this study the extraction of this valuable antioxidant from grape seeds was studied. For the extraction of proanthocyanidins, different solvents such as ethanol, methanol, acetone and their aqueous forms were used. The maximum extraction yield was achieved after 24 h at room temperature. It was observed that 70% aqueous acetone was the best solvent with the highest yield of 17.5%. Yield of proanthocyanidin extracted with 70% aqueous acetone was 3 times greater than proanthocyanidins extracted with other solvents. The extract was freeze dried to obtain the product as powdered form. To compare the product with commercial ones HPLC chromatograms and FTIR spectra were taken and similar spectra were obtained. With HPLC, monomers of proanthocyanidins; (+)-catechin and (-)- epicatechin were determined. (+)-catechin was observed at 17.2 min as 3.06%w/w. Also, (-)-epicatechin was observed at 42.8 min as 1.99%w/w. Most of the drying methods are performed at high temperatures which may result negative effects on proanthocyanidin`s antioxidant capacity. Even the applications at low temperatures in case of freeze-drying have some disadvantages e.g. the process takes a long time, it is expensive and has some difficulties. Therefore as an alternative to other concentration and drying techniques, adsorption process was thought to be a promising technique. Although adsorption of proanthocyanidins on zeolites were not obtained, removal of excess water from the extracts can be achieved by using zeolites. This would possess as a promising technique for the concentration of the end productThe antioxidant capacities of proanthocyanidins from the grape seed extracts were also determined. Proanthocyanidin has an antioxidant capacity with 57 TEAC value, which is more than synthetic antioxidants; BHT, BHA, TBHQ and PG, 6.66, 0.593, 1.168 and 12.62 TEAC respectively. .Master Thesis Screening of Some Plant Species for Their Total Antioxidant and Antimicrobial Activities(Izmir Institute of Technology, 2008) Kaçar, Diren; Bayraktar, OğuzIn 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 Adsorption of Olive Leaf Antioxidants on Silk Fibroin(Izmir Institute of Technology, 2006) Bayçın Hızal, Deniz; Bayraktar, OğuzThis study focused on producing protein based functional food with antioxidative and antimicrobial properties by adsorption of olive leaf antioxidants on silk fibroin. In accordance with this aim, extraction and adsorption of two most abundant polyphenols in olive leaves, oleuropein and rutin were studied. Furthermore, desorption studies were performed to increase the purity of polyphenols.In this study, effect of various parameters on extraction and adsorption were investigated by HPLC and antioxidant analyses. The adsorption isotherms of oleuropein and rutin were plotted at different temperatures, pH values and solid-liquid ratios. After adsorption, the adsorbed polyphenols on silk fibroin was subjected to SEM, FTIR, color, antioxidant and antimicrobial analyses to observe the changes in the silk fibroin.The experimental data of adsorption isotherms were well-fitted to Langmuir model. The maximum adsorption capacity was determined as 108 mg oleuropein/g silk fibroin and 21 mg rutin/g silk fibroin. In desorption process, 81% of rutin and 85 % of oleuropein were removed from the adsorbent surface in 70 % aqueous ethanol solution.After adsorption of oleuropein and rutin, the antioxidant capacity of silk fibroin increased from 1.93 mmol TEAC/g to 3.61 mmol TEAC/g. Silk fibroin also gained antimicrobial activity against Staphylococcus aureus and Klebsiella pneumoniae after adsorption of olive leaf antioxidants. Desorbed polyphenols exhibited higher antioxidant capacity than the same amount of olive leaf extract due to the increase in the purity of oleuropein and rutin after desorption.Consequently, silk fibroin is a promising protein for the production of functional food or dietary supplements and for the purification of oleuropein and rutin.Master Thesis Quantitative trait analysis in solanum lycopersicum x solanum peruvianum(Izmir Institute of Technology, 2009) Yüce, Duygu; Frary, AnneTomato is an important vegetable for both the economy and the human diet and it is a good model system for genetic studies. Because of tomato.s commercial importance, agronomic traits such as yield, fruit weight, size, color and firmness are very significant for the tomato processing industry and fresh consumption. However with increased attention on health, plant breeders also consider the improvement of health related traits of tomato such as antioxidant characters. Improvement of these desired traits is very difficult because many plant traits are controlled by more than one gene. In this study both health-related and agronomically important traits were characterized in an BC2F2 S. peruvianum mapping population of 118 individuals. All plants were phenotypically characterized for total water-soluble antioxidant activity, phenolic and vitamin C contents as well as several agronomic traits including fruit weight and shape, color and firmness. All antioxidant traits showed good variation in the population with the S. peruvianum parent having significantly higher values for all three antioxidant traits. Based on trait distributions and transgressive segregation in the population, it was expected that some alleles from the wild species S. peruvianum had the capacity for improvement of both antioxidant and agronomic traits of cultivated tomato. Both parents were genotypically characterized with 169 genetic markers including 96 COSII and 73 SSR markers. Good levels of polymorphism were identified with both types of marker. Thus, it was shown that the population contains sufficient trait and genotypic variation for efficient mapping of quantitative trait loci.Master Thesis Quatitative Trait Loci Analysis(qtl) of Fruit Characteristics in Tomato(Izmir Institute of Technology, 2008) Ökmen, Bilal; Doğanlar, SamiTomato has a crucial part in the human diet. Therefore, many plant breeders have tried to improve horticulturally important traits such as yield, fruit size, shape and color. With increased attention on human health, plant breeders also consider the improvement of health-related traits of fruits and vegetables such as antioxidant characters. However, because most plant traits are controlled by more than one gene, improvement of crops that possess the desired traits is very difficult.Development of molecular marker techniques makes these processes feasible for plant breeders. In this study both health-related and horticulturally important traits were characterized for identificaton of their locations in the tomato genome using 152 Lycopersicon hirsutum BC2F2 mapping individuals. For this aim, all plants were phenotypically and genotypically characterized. It was expected that some alleles from the wild species L.hirsutum had the capacity for improvement of both antioxidant and agronomically important traits of elite lines.A total of 75 QTLs were identified for all traits. Of the 75 QTLs, 28 were identified for five antioxidant traits including total water soluble antioxidant capacity, vitamin C, phenolic, flavonoids and lycopene content and 47 QTLs were identified for 8 agronomic traits including external and internal fruit color, fruit weight, firmness, fruit shape, stem scar size, locule number and wall thickness. Seventeen of these QTLs were also identified by previous studies. Markers linked with these QTLs can be used in Marker Assisted Selection (MAS) for improvement of elite tomato lines.Master Thesis Characterization and Genetic Mapping of Health Related Traits in Tomato(İzmir Institute of Technology, 2005) Rusçuklu, Dane; Doğanlar, SamiTomato is consumed in the daily diet and has a diverse nutritional content including antioxidants, lycopene, vitamin C and phenolics. However, the content of these compounds in tomato cultivars could be higher. There are two ways of increasing the nutritional quality of tomato. One of them is a transgenic way which is still questioned and is not approved in many countries. The other way is molecular breeding which is based on introgression of wild genes into cultivated tomatoes via the combination of classical breeding with molecular marker analysis. This method lets us obtain nontransgenic tomatoes with increased nutritional quality. In this project a population that was obtained from a cross between wild type L.pimpinellifolium and cultivated tomato L.esculentum was used. This population includes 145 inbred backcross lines (IBLs). It was expected that some individuals of this population had increased nutritional quality derived from the wild parent. In order to test this hypothesis, antioxidant activity of each line was measured. The method used to measure antioxidant activity was based on spectrophotometric measurement which gave mol Trolox equivalent antioxidant activity. It was observed that the IBLs were phenotypically close to L.esculentum and that some individuals did have higher antioxidant activity than the cultivated parent. The population was also mapped with molecular markers and 31 possible QTLs which control antioxidants in tomato were found. The source of alleles associated with increased antioxidant characters was usually L.pimpinellifolium. This result confirmed that wild type tomatoes can be a resource for increasing nutritional quality of tomatoes.