Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 76Citation - Scopus: 82Multicolor Emitting Carbon Dot-Reinforced Pva Composites as Edible Food Packaging Films and Coatings With Antimicrobial and Uv-Blocking Properties(American Chemical Society, 2022) Alaş, Melis Özge; Doğan, Gamze; Yalçın, Mustafa Serkan; Özdemir, Sadin; Genç, RükanActive food packaging has become attractive because of the possibility to provide a longer shelf-life by loading functional agents into the packages to maintain the quality of food products. Herein, photoluminescent and transparent polyvinyl alcohol (PVA)-based composites embedding multicolor fluorescent carbon dots (CD/PVA) were prepared by the solvent casting method. The prepared CDs emit a strong and stable fluorescence in solution while the CD/PVA composite films were transparent, flexible, and showed UV-blocking activity with a strong fluorescence emission. Blue color-emitting CDs showed the highest UV blockage at UVA (87.04%), UVB (87.04%), and UVC (92.22%) regions while PVA alone absorbed only less than 25% of the light in all UV regions. UV blockage capacity was shown to be decreased by half, in line with the emission color shift from blue to red. Thermal properties of the PVA film were improved by the addition of CDs to the polymer, and in vitro cell viability tests showed that none of the CDs were cytotoxic against the human lung fibroblast healthy cell line (MRC-F cells) when integrated into the PVA. The antimicrobial activity of CD/PVA nanofilms was qualitatively determined. The prepared films exhibited good antimicrobial activity against both Gram-positive and Gram-negative bacteria with mild antioxidant and metal chelating activity, and significant inhibition of biofilm formation with a strong link with emitted color and the concentration of the composites. Green- and red-emitting CD/PVA with the highest antimicrobial activity were then analyzed and compared with the plane PVA employing their effect on the shelf-life of strawberries as a model for perishable foods. Fresh strawberries dip coated with CD/PVA and PVA were monitored over time, and virtual evaluations showed that CDs/PVA film coating resulted in reduced weight and moisture loss and significantly inhibited the fungal growth and spoiling for over 6 days at RT and 12 days at fridge conditions maintaining the visual appearance and natural color of the fruit. The findings in this work indicated the potential of reported CD as non-cytotoxic, UV-blocking antimicrobial additives for the development of edible coatings and packages for their use in the food industry, as well as pharmaceutical and healthcare applications.Article Citation - WoS: 13Citation - Scopus: 17Characterization of Antimicrobial Activities of Olive Phenolics on Yeasts Using Conventional Methods and Mid-Infrared Spectroscopy(Springer, 2019) Canal, Canan; Özen, Banu; Baysal, Ayşe HandanOlive fruit is very rich in terms of phenolic compounds. Antimicrobial activities of various phenolic compounds against bacteria and fungi are well established; however, their effects on yeasts have not been examined. Aim of this study was to investigate the antimicrobial effects induced by olive phenolic compounds, including tyrosol, hydroxytyrosol, oleuropein, luteolin and apigenin against two yeast species, Aureobasidium pullulans and Saccharomyces cerevisiae. For this purpose, yeasts were treated with various concentrations (12.5-1000ppm) of phenolic compounds and reduction in yeast population was followed with optical density measurements with microplate reader, yeast colony forming units and mid-infrared spectroscopy. All phenolic compounds were effective on both yeasts, especially 200ppm and higher concentrations have significant antimicrobial activity; however, effects of lower levels depend on the type of phenolic compound. According to mid-infrared spectral data, significant changes were observed in 1200-900cm(-1) range corresponding to carbohydrates of yeast structure as a result of exposure to all phenolic compounds except tyrosol. Spectra of tyrosol and luteolin treated yeasts also showed changes in 1750-1500cm(-1) related to amide section and 3600-3000cm(-1) fatty acid region. Since phenolic compounds from olives were effective against yeasts, they could be used in food applications where yeast growth showed problem. In addition, FTIR spectroscopy could be successfully used to monitor and characterize antimicrobial activity of phenolic compounds on yeasts as complementary to conventional microbiological methods.Article Citation - WoS: 12Citation - Scopus: 18Synergistic Antimicrobial Effects of Activated Lactoferrin and Rosemary Extract in Vitro and Potential Application in Meat Storage(Springer Verlag, 2020) Soyer, Ferda; Keman, Deniz; Eroğlu, Erdal; Türe, HasanThis study aimed to explore the antimicrobial effects of activated lactoferrin (ALF) and rosemary extract (RE) on Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes, and to investigate their application potential in the meat storage. Minimum inhibitory concentrations (MICs) of ALF, RE and ALF-RE combinations were determined via microtiter plate assay. MICs of ALF were 1% for E. coli O157:H7; 0.5% for S. Enteritidis and 0.1% for L. monocytogenes. While 15% RE inhibited L. monocytogenes; 30% RE partially inhibited E. coli O157:H7 and S. Enteritidis growth. Synergistic effect of ALF and RE on the inhibition of E. coli O157:H7 increased the activity of ALF two to three folds. Food application of antimicrobials was performed by dipping of meat samples. Both ALF and RE were found effective in the prevention of L. monocytogenes growth about two logs. According to the data, choice of natural antimicrobials may be promising in food preservation.Article Citation - WoS: 96Citation - Scopus: 113Hypericum Perforatum Incorporated Chitosan Films as Potential Bioactive Wound Dressing Material(Elsevier Ltd., 2017) Güneş, Seda; Tıhmınlıoğlu, FundaRecent studies in wound dressing applications offer new therapies and promote wound healing process. The aim of this study was to develop Hypericum perforatum (St John's Wort) oil incorporated chitosan films for wound dressing applications. H. perforatum oil as a potential therapeutic agent was encapsulated in chitosan film to achieve a better wound dressing material. Oil incorporated chitosan films were successfully prepared by solvent casting method in different oil concentrations (0.25–1.5%v/v). Water vapor permeability (WVP), mechanical test, swelling behavior and surface hydrophobicity were performed in order to characterize the prepared films. Antimicrobial test was performed by disc diffusion method and the growth inhibition effects of the films including different amount of H. perforatum oil were investigated on Escherichia coli and Staphylococcus aureus. WVP increased with oil incorporation and the highest value was obtained for 0.25% oil concentration.The highest strain value was obtained in 0.25% oil content films although tensile stress decreased with increasing oil content. H. perforatum oil incorporated films had antimicrobial effect on both microorganisms. Chitosan based films had no cytotoxic effects on NIH3T3fibroblast cells and provided a good surface for cell attachment and proliferation. The results showed that the H. perforatum incorporated chitosan films seems to be a potential and novel biomaterial for wound healing applications.Article Citation - WoS: 66Citation - Scopus: 82Antimicrobial and Antioxidant Activities of Turkish Extra Virgin Olive Oils(American Chemical Society, 2010) Karaosmanoğlu, Hande; Soyer, Ferda; Özen, Banu; Tokatlı, FigenTurkish extra virgin olive oils (EVOO) from different varieties/ geographical origins and their phenolic compounds were investigated in terms of their antimicrobial and antioxidant properties in comparison to refined olive, hazelnut, and canola oils. Antimicrobial activity was tested against three foodborne pathogenic bacteria, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis. Although all EVOOs showed a bactericidal effect, the individual phenolic compounds demonstrated only slight antimicrobial activity. Moreover, refined oil samples did not show any antimicrobial activity. Among the phenolic compounds, cinnamic acid (2 mg/kg of oil) had the highest percent inhibition value with 0.25 log reduction against L. monocytogenes. The synergistic interactions of tyrosol, vanillin, vanillic, and cinnamic acids were also observed against Salmonella Enteritidis. The antioxidant activities of oils were tested by β-carotene-linoleate model system and ABTS method. In both methods, EVOOs showed higher antioxidant activities, whereas refined oils had lower activity. The ABTS method provided a higher correlation (0.89) with total phenol content. © 2010 American Chemical Society.