Browsing by Author "Seçkin A.K."

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    Acid adaptation effect on survival of Escherichia coli O157:H7 in fermented milk products
    (2007) Tosun H.; Seçkin A.K.; Aktuǧ Gönöl Ş.
    The growth and survival of acid-adapted and nonadapted Escherichia coli O157:H7 were determined in strained, set-type, and synbiotic yoghurt and kefir. Acid-adapted or nonadapted E. coli O157:H7 were inoculated into the synbiotic and set-type yoghurt before and after the fermentation process. Survival of the inoculated E. coli O157:H7 in these products was examined during storage at 4 °C. Acid adaptation enhanced the survival of E. coli O157:H7 in kefir and strained yoghurt. Acid adaptation also enhanced the survival of E. coli O157:H7 in set-type yoghurt, which was inoculated after the fermentation process; however, acid-adapted cell inoculation before fermentation did not enhance survival. These observations support the theory that acid adaptation is an important survival mechanism enabling E. coli O157: H7 to persist in fermented dairy products. © TÜBİTAK.
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    Changes in some components of the muscle lipids of three freshwater fish species under natural extreme cold and temperate conditions
    (2008) Uysal K.; Bübül M.; Dönmez M.; Seçkin A.K.
    Fatty acid composition, conjugated linoleic acid and cholesterol contents in the muscles of three freshwater fish species (Barbus plebejus escherichi, Capoeta capoeta capoeta and Rutilus rutilus) were determined under natural extreme temperate (July) and cold (January) conditions. The aim of the study was to determine whether there were differences in these components of the muscle lipids among these three fish species under extreme natural conditions. Samples were analyzed using gas chromatography. Palmitic, oleic, docosahexaenoic and eicosapentaenoic acids were the predominant fatty acids in all fish in both months. The percentages of polyunsaturated fatty acids, n - 3 polyunsaturated fatty acids, n - 6 polyunsaturated fatty acids and eicosapentaenoic + docosahexaenoic acids in the muscle of B. plebejus escherichi and C. capoeta capoeta were significantly higher in January (P < 0.05) than in July. The ratio of n - 6 to n - 3 polyunsaturated fatty acids was lower than 0.60 in all fish species, with C. capoeta capoeta showing the lowest ratio in January (0.36). The levels of cholesterol and conjugated linoleic acid ranged from 103.46 to 150.10 mg/100 g oil and from 16.27 to 35.45 mg/100 g oil, respectively, for all samples in both months. There were no statistical differences in cholesterol levels among the three fish species in July and January. Conjugated linoleic acid contents were significantly higher in January in B. plebejus escherichi and C. capoeta capoeta. Of the three species tested, the extreme temperate and cold conditions affected B. plebejus escherichi the most. © Springer Science+Business Media B.V. 2008.
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    Cholesterol content and fatty acid profile of chocolates mostly consumed in Turkey Contenido de colesterol y perfil de ácidos grasos de los chocolates más consumidos en Turquía
    (2010) Ergönül P.G.; Ergönül B.; Seçkin A.K.
    Cholesterol content and fatty acid profile of chocolates that are consumed in Turkey were determined by capillary gas chromatography. Chocolate samples from 20 trade marks were purchased from markets in İzmir, Turkey. As results of the analyses, average cholesterol content of the samples was 1.14 ± 0.14 mg/kg ranging between 0.963 and 1.535 mg/kg. Twenty-three types of fatty acids were determined in oil extracted from chocolates. Main fatty acids found in chocolate samples were stearic acid (39.33 ± 5.25%), oleic acid (25.99 ± 6.89%), and palmitic acid (25.56 ± 2.06%). Total saturated and total unsaturated fatty acid contents of chocolate samples were found as 69.90% and 30.05%, respectively. The fat content of the samples were in the range 31.5–67%. © 2010 Taylor & Francis Group, LLC.
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    Effects of prebiotics (inulin and fructooligosaccharide) on quality attributes of dried yoghurt (kurut)
    (2010) Seçkin A.K.; Ergönül B.; Tosun H.; Ergönül P.G.
    Chemical and microbiological attributes of prebiotic kurut were investigated. Prebiotic kurut was obtained by adding inulin and fructooligosaccharide into strained yoghurt. Chemical attributes and microbiological analysis like total mesophylic aerobic bacteria, yeast and mold, lactic acid bacteria and total coliform bacteria counts were determined. Textural analyses of kuruts were also performed by texture analyzer. It was determined that using different amounts and types of polysaccharides in formulation did not affect the pH and aw values, salt, ash, protein, water, fat and cholesterol contents and acidity values of the samples (p > 0.05). Also, firmness values, total mesophylic aerobic bacteria, lactic acid bacteria and coliform counts of kurut samples were not affected by using added polysaccharides in formulation (p>0.05), whereas total yeast and mould counts of kuruts were affected by the formulation (p<0.05).
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    Chemical and textural attributes of hellim (Halloumi) cheese mv arketed in Turkey; [Kemijska i teksturalna svojstva Hellim (Halloumi) sira na tržištu u Turskoj]
    (2011) Ergönül B.; Ergönül P.G.; Seçkin A.K.
    Chemical and textural properties of Hellim (Halloumi) cheese marketed in Turkey were determined in this research. Cheese samples were collected from manufacturers in Turkey and according to data obtained, water amounts of samples were changing in a wide range of 34.07-55.92%, whereas the average pH values of the samples was 5.91±0.36. Cholesterol contents of the samples were low and changing among 7.54-14.79 mg/100 g. Average fat and protein amounts of samples were 25.43±1.7 (%), and 22.81±5.62 (%) respectively, and 30.31±1.15 (%) of the fat fraction was composed of unsaturated fatty acids. Main organic acids determined in samples were citric, lactic and propionic acids. Also, hardness, chewiness, adhesiveness, cohesiveness and gumminess scores of the samples were determined by TPA analysis and Hunter color scores were evaluated.
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    Influence of a vegetable fat blend on the texture, microstructure and sensory properties of kashar cheese
    (2011) Dinkçi N.; Kesenkaş H.; Seçkin A.K.; Kinik Ö.; Gönç S.
    The possibility of using a commercial vegetable fat blend in Kashar cheese was investigated. Kashar cheeses were manufactured by replacing the milk fat (MF) with a vegetable fat (VF) blend. Kashar cheeses from whole milk were also manufactured to compare textural, microstructural, meltability, color and sensory characteristics during a ripening period of 90 days. The use of vegetable fat decreased the meltability, hardness, cohesiveness, gumminess and chewiness of the cheese; while increasing adhesiveness where springiness was not affected. Differences became less notable toward the end of ripening. Scanning electron micrographs displayed VF cheese with a compact network with small and uniform fat globules embedded in the protein matrix. The MF cheese exhibited an open protein matrix containing milk fat globules of various sizes and forms. The color analysis demonstrated significant differences between cheeses. Finally, all sensory characteristics of the cheese were affected by the vegetable fat blend.
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    Ochratoxin A in grape pekmez (grape molasses) consumed in Turkey
    (2014) Tosun H.; Yildiz H.; Obuz E.; Seçkin A.K.
    In this study, ochratoxin A (OTA) in 55 home-made, 20 commercial and 7 organic grape pekmez (grape molasses) produced in Turkey was investigated. OTA was detected in 73% of home-made pekmez samples, in 35% of commercial pekmez samples and in 71% of organic pekmez samples. Eleven per cent of the samples had OTA levels higher than 10 μg/l. The highest OTA level (31 μg/l) was detected in organic pekmez. The maximum OTA levels were 15 μg/l and 12 μg/l in home-made and commercial pekmez samples, respectively. Mean OTA levels were 3.5 μg/l, 1.4 μg/l and 9.2 μg/l in home-made, commercial and organic pekmez samples, respectively. Organic pekmez samples and home-made pekmez samples had higher OTA contamination than commercial pekmez samples. Results confirm OTA contamination in grape pekmez samples, indicating that the OTA level in grape pekmez could be a potential risk for consumers. © 2013 © 2013 Taylor & Francis.