WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Conference Object Citation - Scopus: 2Preparation and Characterization of Hydroxyapatite/Calcium Phosphate Powders(Trans Tech Publications, 2004) Şimşek, Deniz; Harsa, Hayriye Şebnem; Çiftçioğlu, Rukiye; Şimşek, Deniz; Harsa, Şebnem; 03.02. Department of Chemical Engineering; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe preparation of calcium phosphate based powders through chemical precipitation in order to determine the optimum conditions for the preparation of stoichiometric, thermally stable hydroxyapatite (HA) powders was investigated in this work. The effects of parameters like pH, aging time, and heat treatment temperature on the phase structure and morphology of the powders were investigated by SEM and XRD.HA was prepared at a Ca/P ratio of 1.67. The precipitation pH had a profound influence on the morphology and crystallite size of the powders in the 4-11 pH range. Relatively large 5 mum prismatic particles were obtained at low pH whereas the powders were formed from agglomerates of nano sized particles at high pH. Powders had a HA dominant phase structure above a pH of 8. Phase pure HA powders were obtained with close to theoretical yields at pH = 10 and 11. The crystallite sizes of the powders varied from about 30 nm at 90degreesC to 50-90 mn at 1250degreesC with the smallest crystallite sizes obtained for pH 10 and 11 powders at 1250degreesC. The crystallite size increased significantly with aging temperature.Article Citation - WoS: 7Citation - Scopus: 11Effects of Light, Carbon Dioxide, and Hormone Levels on Transformation To Photoautotrophy of Sugarcane Shoots in Micropropagation(American Society of Agricultural Engineers, 2000) Ertürk, Handan; Ertürk, Handan; Walker, Paul N.; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologySugarcane (Saccharum spp.) shoots were transferred from a heterotrophic micropropagation environment and cultured on sugar-free Murashige and Skoog (MS) salts medium in the controlled atmosphere of a growth chamber. The purpose was to achieve photoautotrophic shoot culture to be used for micropropagation. Effects on the shoots were tested for three factors: Carbon dioxide concentration, light level, and the hormone concentration of the growth medium. Factorial design was applied for the experiment such that all combinations of high and low factor levels were utilized, and the medium level of each factor level constituted the middle point of the design. All shoots were observed to become yellowish in color and lose vigor in the sugarless environment, although the successful treatments regained their color and vigor. Average dry weights of shoots per vessel were recorded at the end of two weeks as a quantitative measure of transformation of shoots to photoautotrophy. Light and CO2 levels were found to have statistically significant and positive effects. The negative effect of hormone concentration was insignificant.Article Efficacy of Selected Chemicals on Survival of Salmonella on Turkey Meat(Lavoisier, 2007) Baysal, Ayşe Handan Dinçer; Baysal, Ayşe Handan; Ünlütürk, Adnan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe influence of dipping Salmonella inoculated turkey breast meat in lactic acid (LA), fumaric acid (FA), trisodium phosphate (TSP) and sodium tripolyphosphate (STPP) solutions on the elimination of S.typhimurium was assessed. Dipping fillets in 1% LA, 1.5% LA, 0.5% FA, 10% TSP and 10% STPP reduced the number of S.typhimurium by about 1.9, 2.7, 2.6, 3.5 and 3.2 log units, respectively. While there was only one Salmonella positive sample out of three samples 2 hours after dipping the fillets with an initial inoculum of 3.1 log CFU Salmonella per fillet in 1.5% LA solution, no Salmonella positive sample was observed out of three samples dipped in 10% TSP solution. There were no Salmonella positive samples with an initial inoculum of 3.1 log CFU Salmonella per fillet after 2 and 24 hours of dipping in 10% TSP solution. There were no Salmonella positive fillets out of three samples dipped in 1.5% LA and 10% TSP solution with an initial inoculum of 2.6 log CFU Salmonella per fillet after 2 and 24 hours period.Article Citation - WoS: 1Citation - Scopus: 2Effects of Selected Chemicals on Microbial Stability of Turkey Meat(Lavoisier, 2007) Baysal, Ayşe Handan Dinçer; Baysal, Ayşe Handan; Ünlütürk, Adnan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe influence of dipping turkey breast meat in lactic acid (LA), fumaric acid (FA), lactic acid plus fumaric acid (LA + FA), trisodiurn phosphate (TSP) and sodium tripolyphosphate (STPP) solutions on aerobic mesophilic, psychrotrophic bacteria and yeast counts were assessed. 1-1.5% LA, 0.5% FA and 1% LA + 0.5% FA showed immediate inhibitory effects on aerobic mesophilic bacteria (0.3-0.6, 0.4 and 1.8 log unit reductions, respectively). 0.5% FA reduced psychrotrophic bacteria and yeast counts on fresh turkey breast fillets immediately by 1.1 and 0.4 log units, respectively. 5% TSP reduced aerobic mesophilic and psychrotrophic bacteria by 0.4 and 0.5 log units, respectively on breast fillets. 5% STPP reduced the yeast count on breast fillets immediately by 0.7 log unit. 1% LA, 0.5% FA and 1% LA + 0.5% FA reduced the psychrotrophic bacteria counts by 0.48, 0.23 and 1.27 log units after 8 days of storage, respectively in comparison to the untreated control samples. 1% LA + 0.5% FA treated fillets had a detectable discoloration and acid odour although there was no microbial spoilage at 14 days of storage. Dipping fillets in both 1% LA and 0.5% FA extended the storage life up to 4 days, without adversely affecting the colour.Article Citation - Scopus: 1Effect of Atrazine on Algal Contamination and Sugarcane Shoots During Photoautotrophic Micropropagation(American Society of Agricultural Engineers, 2003) Ertürk, Handan; Ertürk, Handan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyA laboratory procedure was developed for obtaining and maintaining photoautotrophic cultures ofsugarcane shoots in vitro for three generations. Algae contamination in vessels was a problem for photoautotrophic growth under septic conditions. Atrazine, a herbicide, was effective in controlling algae at a concentration of 10 ppm, but the growth of shoots in herbicide-treated sugarless Murashige and Skoog (MS) medium decreased to about half of the growth in untreated medium. As a result, atrazine was not considered to be a practical solution for algae control. Additional work is needed to optimize photoautotrophic micropropagation of sugarcane for both septic and aseptic conditions. Photoautotrophic micropropagation of sugarcane may be economical only if culture can be perfected under septic conditions.Article Citation - WoS: 18Citation - Scopus: 18Surface Energetics To Assess Biomass Attachment Onto Hydrophobic Interaction Adsorbents in Expanded Beds(Elsevier Ltd., 2009) Vennapusa, Rami Reddy; Tarı, Canan; Tarı, Canan; Cabrera, Rosa; Fernandez-Lahore, Marcelo; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyCell-to-support interaction and cell-to-cell aggregation phenomena have been studied in a model system composed of intact yeast cells and Phenyl-Streamline adsorbents. Biomass components and beaded adsorbents were characterized by contact angle determinations with three diagnostic liquids and zeta potential measurements. Subsequently, free energy of interaction vs. distance profiles between interacting surfaces was calculated in the aqueous media provided by operating mobile phases. The effect of pH and ammonium sulphate concentration within the normal operating ranges was evaluated. Calculation indicated that moderate interaction between cell particles and adsorbent beads can develop in the presence of salt. Cell-to-cell aggregation was suspected to occur at high salt concentration and neutral pH. Predictions based on the application of the XDLVO approach were confirmed by independent experimental methods like biomass deposition experiments and laser diffraction spectroscopy. Understanding biomass attachment onto hydrophobic supports can help in alleviating process limitations normally encountered during expanded bed adsorption of bioproducts.Article Citation - WoS: 153Citation - Scopus: 192Development of Cellulose Acetate Based Antimicrobial Food Packaging Materials for Controlled Release of Lysozyme(Elsevier Ltd., 2009) Gemili, Seyhun; Yemenicioğlu, Ahmet; Alsoy Altınkaya, Sacide; Yemenicioğlu, Ahmet; 03.02. Department of Chemical Engineering; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAntimicrobial packaging materials were obtained by incorporation of lysozyme into cellulose acetate (CA) films. In order to achieve controlled release of lysozyme, the structure of the films was changed from highly asymmetric and porous to dense by modulating the composition of the initial casting solution. The highest release rate, soluble lysozyme activity and antimicrobial activity were obtained with the film prepared from 5% CA solution including 1.5% lysozyme. Increasing CA content in the casting solution decreased the porosity of the films, hence, reduced the release rate, maximum released lysozyme activities and the antimicrobial activities of the films. In contrast, immobilized lysozyme activities and the tensile strength of the films increased. The incorporation of lysozyme did not cause significant reductions in tensile strength and elongation at break values except in films prepared with 15% CA. This study showed the good potential of asymmetric CA films to achieve controlled release in antimicrobial packaging.Article Citation - WoS: 23Citation - Scopus: 29Physical Properties of Biopolymers Containing Natamycin and Rosemary Extract(John Wiley and Sons Inc., 2009) Türe, Hasan; Özen, Fatma Banu; Eroğlu, Erdal; Soyer, Ferda; Özen, Banu; Soyer, Ferda; 04.03. Department of Molecular Biology and Genetics; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyAntifungal biopolymers were prepared by incorporating natamycin (NA) and NA + rosemary extract (RE) into wheat gluten (WG) and methyl cellulose (MC) films. Interaction between antimicrobial agents and biopolymers was determined with mid-infrared spectroscopy and scanning electron microscopy (SEM). Water vapour permeability and mechanical properties of these films were also measured. Mid-infrared spectroscopy did not indicate any interaction. SEM observations showed that NA crystallises at high concentrations in biopolymers. There were no significant changes in water vapour permeabilities of biopolymers containing active agents at P < 0.05. While NA incorporation did not result in any changes in mechanical properties of WG films a reduction in tensile strength was observed for MC films containing high concentration of NA. In general, active agent incorporation into WG and MC films did not result in any considerable changes in their physical properties that could affect their application.Article Citation - WoS: 36Citation - Scopus: 38Antimicrobial Activity of Lactoperoxidase System Incorporated Into Cross-Linked Alginate Films(John Wiley and Sons Inc., 2009) Yener, Fatih Yalçın Güneş; Korel, Figen; Yemenicioğlu, Ahmet; Korel, Figen; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, the antimicrobial effect of lactoperoxidase (LPS) incorporated alginate films was investigated on Escherichia coli (NRRL B-3008), Listeria innocua (NRRL B-33314), and Pseudomonas fluorescens (NRRL B-253) in presence of different concentrations of H2O2 (0.2, 0.4, and 0.8 mM) and KSCN (1, 2, and 4 mM). The incorporation of 70 nmol ABTS/min/cm2 LPS into alginate films gave 0.66 to 0.85 nmol ABTS/min/cm2 enzyme activity at 0.2 to 0.8 mM H2O 2 concentration range. The antimicrobial activity of LPS system on target bacteria changed according to the concentrations of KSCN and H 2O2. The growth of all tested bacteria was prevented for a 6-h period by applying LPS system in presence of 0.4 or 0.8 mM H 2O2 and 4 mM KSCN. At 0.8 mM H2O2 and 4 mM KSCN, the LPS system also inhibited growth of L. innocua and P. fluorescens for a 24-h incubation period, whereas E. coli growth could not be inhibited for 24 h under these conditions. At 0.2 mM H2O2 and 1 to 4 mM KSCN, a considerable inhibitory effect was obtained only on P. fluorescens. The decreasing order of the resistance of studied bacteria to LPS system is as follows: E. coli, L. innocua, and P. fluorescens. The developed antimicrobial system has a good potential for use in meat, poultry, and seafood since alginate coatings are already used in these products. Further studies are needed to test the LPS incorporated edible films in real food systems.Article Citation - WoS: 94Citation - Scopus: 106Distribution of Simple Phenols, Phenolic Acids and Flavonoids in Turkish Monovarietal Extra Virgin Olive Oils for Two Harvest Years(Elsevier Ltd., 2009) Ocakoğlu, Derya; Tokatlı, Figen; Korel, Figen; Korel, Figen; Özen, Fatma Banu; Tokatlı, Figen; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyMonovarietal extra virgin olive oils extracted from six dominant and economically important Turkish olive cultivars (memecik, erkence, domat, nizip-yaglik, gemlik, ayvalik) were examined for their simple phenolics, phenolic acids and flavonoid compounds over 2005 and 2006 harvest years. Total phenol contents, oxidative stabilities and chromatic ordinates as colour parameters were also measured. The most typical phenolic compounds that were identified in both years are hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, cinnamic acid, luteolin, and apigenin. Multivariate data were analysed by principal component and partial least square-discriminant analyses. It was observed that phenolic profiles of olive oils depended highly on harvest season. In addition, oils of different olive cultivars have different distribution of phenols. No significant correlation was observed between oxidative stability and phenolic compounds. Increase in peroxide value over an accelerated oxidation period of 11 days showed weak correlations with total phenol content, vanillin, syringic acid and colour parameter a*, as 0.56, 0.55, -0.42, and 0.51, respectively, in terms of correlation coefficient r.