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    Detection of seagull meat in meat mixtures using real-time PCR analysis
    (ELSEVIER SCI LTD, 2013) Kesmen, Zulal; Celebi, Yasemin; Gulluce, Ayten; Yetim, Hasan
    The possibility of the adulteration of meat products with seagull meat disturbs people living in coastal cities. In order to eliminate the suspicions of consumers a sensitive and reliable method is needed for the detection of seagull meat. In order to identify and quantify seagull meat in meat mixtures a real-time polymerase chain reaction (PCR) assay, using species-specific primers and a TaqMan probe was designed on the mitochondrial NADH dehydrogenase subunit 2 gene. In addition, it was possible to detect the template DNA of seagull at the level of 100 pg without any cross-reactivity with non-target species (bovine, ovine, donkey, pork, horse, chicken, turkey, goose, duck). Also, the method was capable of detecting seagull meat at the level of 0.1% in raw and heat-treated test mixtures, prepared by mixing seagull meat with beef and chicken at different levels (0.01-10%). In conclusion, it can be suggested that the real-time PCR assay used in this research could be a rapid and sensitive method for the routine identification of seagull meat in raw or cooked meat products. (C) 2013 Elsevier Ltd. All rights reserved.
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    Differentiation of black tea according to country of origin using the μ-CTE/TD/GC-MS method combined with decision tree-optimizable neural network analysis
    (Wiley, 2025) Okuyan, Nurullah; Yetim, Hasan; Kesmen, Zulal
    BACKGROUNDAccurate discrimination of the country of origin of teas is critical to determine their actual commercial value, to meet consumer preferences, and to ensure compliance with labeling regulations. Therefore, in this study, we developed a new approach to accurately discriminate the country of origin of teas in the Turkish market.RESULTSA thermal desorption/gas chromatographic-mass spectrometric (TD/GC-MS) method combined with optimizable neural networks (ONN) was developed to analyze the volatile organic compounds (VOCs) of tea samples subjected to infusion or grinding pretreatments. Prior to GC-MS analysis, the conventional thermal desorption method was applied to VOCs in the powdered teas, while VOCs in the infused teas were adsorbed on Tenax-TA sorbent tubes attached to a micro-chamber/thermal extractor (mu-CTE) and then thermally desorbed. Using a feature selection technique, a total of 11 VOCs from infused tea samples, 21 VOCs from ground tea samples, and 18 VOCs from both groups were identified as specific VOCs that critically affect the classification of the teas. As a result of ONN classification of selected VOCs from only ground tea samples and infused tea samples, 95.51% and 96.7% accuracy was obtained, respectively, while 100% classification accuracy was achieved by ONN classification of VOCs from both sample groups.CONCLUSIONThe results showed that different pretreatments applied to Turkish and Ceylon teas caused the release of different volatile compounds, resulting in more specific VOC profiles. In addition, the developed mu-CTE/TD/GC-MS method allowed a more accurate classification of the black tea samples than the TD/GC-MS system alone. (c) 2025 Society of Chemical Industry.
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    Microplastic Release from Single-Use Plastic Beverage Cups
    (Mdpi, 2024) Akbulut, Selen; Akman, Perihan Kubra; Tornuk, Fatih; Yetim, Hasan
    Microplastics (MPs) have attracted considerable attention as one of the most remarkable food and drink pollutants in recent years. Disposable cups, which are widely used as single-use containers, have been suspected as the primary sources of MPs found in cold and hot beverages. In this study, the effect of different exposure times (0, 5, 10 and 20 min) and temperatures (4 degrees C, 50 degrees C and 80 degrees C) on MP release from the single-use cups made of four different materials [polypropylene (PP), polystyrene (PS), polyethylene (PE) coated paper cups and expanded polystyrene (EPS)] into the water was investigated. The number of MPs ranged from 126 p/L to 1420 p/L, while the highest and lowest counts were observed in the PP (50 degrees C for 20 min) and PE-coated paper cups (4 degrees C 0 min), respectively. Washing the cups with ultrapure water prior to use reduced the MP release by 52-65%. SEM images demonstrated the abrasion on the surface of the disposable cups as a result of hot water exposure. Intensities of FTIR absorbance levels at some wavelengths were decreased by the water treatment, which could be evidence of surface abrasion. The annual MP exposure of consumers was calculated as 18,720-73,840 by the consumption of hot and cold beverages in disposable cups. In conclusion, as the level and potential toxicity of MP exposure in humans are not yet fully known, this study sheds light on the number of MPs transferred to cold and hot beverages from single-use disposable cups.