Yazar "Koseoglu, O." seçeneğine göre listele

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    Determination of deficit irrigation treatments on olive fruit quality and olive oil (Memecik cv.) chemical composition and antioxidant properties
    (Innovhub Ssi-Area Ssog, 2019) Sevim, D.; Koseoglu, O.; Gungor, F. Ozturk; Kaya, U.; Kadiroglu, P.; Mengu, G. Pamuk; Akkuzu, E.
    In this research, the influences of irrigation treatments (K1, K2, K3, K4, K5) on chemical properties, antioxidant compounds and activities of table olive and olive oils (Memecik) were investigated during three crop seasons (2012/13, 2013/14 and 2014/15). The three least irrigated (K3, K4 and K5) and non -irrigated (K1) regimes indicated that higher content of polyphenols of olive fruits were those with the most irrigated regime (K2). According to L, a* and b, results of statistical differences were determined between the treatments of K1 and K5 (P<0.05). There was no significant effect determined between irrigation treatments of the Memecik olive oil main fatty acids such as palmitic (C16:0), oleic (C18:1) and linoleic (C18:2) acid, except palmitic acid (first year) and linoleic acid (second year). When we look at the triacylglycerol (TAG) composition in the 2012/13 and 2013/14 crop seasons important statistical differences were determined between the irrigation treatments on some TAG contents (P<0.05) however these differences between irrigation treatments, although statistically significant, are very slight. During the last crop season, no significant effects were determined in the TAG composition between irrigation treatments. During the first and the second year, important statistical differences were observed between the irrigation treatments both for the total phenol content and bitterness index (K225) value of oils (P<0.05). The research showed that the K225 value of Memecik olive oils is above 0.360 value. Important differences were determined between the irrigation treatments on the alpha tocopherol content (P<0.05). DPPH' (2,2-diphenyl-1-picrylhy-drazyl) content (first and second year) and ABTS'+ (2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid) content (all crop seasons) were also significantly influenced by irrigation treatments due to changes in antioxidant compounds (P<0.05). Whereas all these differences, although statistically important, are very slight. In the light of the findings of this research, it was concluded that the use of the restricted irrigation regimes enabled water to be saved with very slight change in fruit and oil quality.
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    Elucidation of key odorants and sensory properties of five different extra virgin olive oils from Turkey
    (Consejo Superior Investigaciones Cientificas-Csic, 2023) Sevim, D.; Koseoglu, O.; Kadiroglu, P.; Güçlü, G.; Ulas, M.; Selli, S.
    The present study investigates the aroma, key odorants and sensory profile of extra virgin olive oils from five well-known Turkish cultivars. The aromatic extract obtained by the purge and trap extraction system, according to a sensory analysis, resembled the odor of olive oil. A total of 22, 21, 18, 22 and 21 aroma-active compounds were detected in the extracts of Ayvalik, Memecik, Gemlik, Sari Ulak and Beylik olive oils, respectively. The results show that Ayvalik has the highest flavor dilution (FD) value of 1024 with hex -anal, (E)-2-hexenal and & alpha;-farnesene. Memecik has the highest FD value at 2048 with (E)-2-hexenal. Gemlik has the highest FD value of 1024 with (Z)-3-hexenyl acetate, (E)-2-hexen-1-ol and & alpha;-farnesene. Sari Ulak has the highest FD value at 2048 with (E)-2-hexenal. Beylik has the highest FD value of 2048 with (E)-2-hexenal and hexanal. All cultivars represent the characteristic green, cut-grass, fruity odor notes.
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    Öğe
    Influence of microwave heating on quality parameters and chemical characteristics of Turkish olive oils
    (Innovhub Ssi-Area Ssog, 2018) Sevim, D.; Koseoglu, O.; Casale, M.; Altunoglu, Y.; Kadiroglu, P.
    Microwave use has become quite common and microwave ovens are being used increasingly due to their fast heating technology. In this study, the effects of microwave heating on the deterioration of olive oil quality parameters like free fatty acidity, peroxide value, ultraviolet absorbance values (K232, K270) and also antioxidant compounds as chlorophyll and carotenoid content, alpha-tocopherol content, total phenolic content in addition oxidative stability and DPPH center dot radical scavenging activity which are related to chemical characteristics of Turkish olive oils, were investigated, at different times of the microwave treatment, in 2015/16. All analytical data were processed through univariate and multivariate data analysis (Principal Component Analysis). It was determined that heating time significantly influences quality parameters and chemical characteristics. This heating treatment produces significant losses in olive oil quality parameters and also in bioactive components. Therefore, heating time should be reduced to minimum to preserve olive oil nutritional content.