PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 3Citation - Scopus: 3Chromatographic Analysis for Targeted Metabolomics of Antioxidant and Flavor-Related Metabolites in Tomato(Bio-Protocol, 2021) Gürbüz Çolak, Nergiz; Tek, Neslihan; Frary, Anne; Doğanlar, SamiTargeted metabolomics is a useful approach to evaluate crop breeding studies. Antioxidant and flavor-related traits are of increasing interest and are considered quality traits in tomato breeding. The present study presents chromatographic methods to study antioxidants (carotenoids, vitamin C, vitamin E, phenolic compounds, and glutathione) and flavor -related characters (sugars and organic acids) in tomato. Two different extraction methods (for polar and apolar entities) were applied to isolate the targeted compounds. The extraction methods developed in this work were time and cost-effective since no further purification was needed. Carotenoids, vitamin C, glutathione, and phenolic acids were analyzed by HPLC-PDA using a RP C18 column at an appropriate wavelength for each compound. Vitamin E and sugars were analyzed by HPLC with RP C18 and NH2 columns and detected by FLD and RI detectors, respectively. In addition, organic acids were analyzed with GC-FID using a Rtx 5DA column after derivatization with MSTFA. As a result, sensitive analytical methods to quantify important plant metabolites were developed and are described herein. These methods are not only applicable in tomato but are also useful to characterize other species for flavor-related and antioxidant compounds. Thus, these protocols can be used to guide selection in crop breeding.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: 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.