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    INFLUENCE OF SUPERCRITICAL CARBON DIOXIDE AND METHANOLIC EXTRACTS OF ROSEMARY ON OXIDATION AND SENSORY PROPERTIES OF WHEAT GERM OIL
    (Wiley-Hindawi, 2009) Yesil-Celiktas, Ozlem; Isleten, Muge; Karagul-Yuceer, Yonca; Bedir, Erdal; Vardar-Sukan, Fazilet
    Both supercritical CO2 and methanolic extracts from the leaves of rosemary (Rosmarinus officinalis) harvested from three different locations of Turkey at four different times of the year were added at a concentration of 100 mg/kg to wheat germ oil. Wheat germ oil samples were stored in an incubator for 10 days at 50C in order to promote oxidation and for the efficacy of the extracts for stabilization purposes to be examined. Degree of oxidation was determined by peroxide and p-anisidine values, which were performed every 2 days. Extracts from Mersin and Canakkale regions performed better results. Additionally, June and September harvests had lower peroxide values. According to the descriptive sensory analysis, both locations and extraction methods were found to effect flavor. Some flavor attributes, such as wheatlike/starchy, fishy and rubbery/metallic changed during storage regardless of locations and extraction methods. Supercritical CO2 extracts performed better results in terms of both oxidation and sensory properties. PRACTICAL APPLICATIONS From the perspective of the food industry, wheat germ oil stabilized with a natural antioxidant such as rosemary can be marketed as a functional product that can create a niche. Rosemary extracts containing higher amounts of rosmarinic acid and carnosic acid should be preferred in order to provide a better shelf life of an edible oil such as wheat germ oil.
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    Microwave-assisted digestion combined with silica-based spin column for DNA isolation from human bones
    (Academic Press Inc Elsevier Science, 2015) Ozdemir-Kaynak, Elif; Yesil-Celiktas, Ozlem
    A protocol for the extraction of DNA from ancient skeletal material was developed. Bone specimen samples (powder or slice), buffer, pretreatment, and extraction methodologies were compared to investigate the best conditions yielding the highest concentration of DNA. The degree of extract contamination by polymerase chain reaction (PCR) inhibitors was compared as well. Pretreatment was carried out using agitation in an incubator shaker and microwave digestion. Subsequently, DNA from bones was isolated by the classical organic phenol-chloroform extraction and silica-based spin columns. Decalcification buffer for total demineralization was required as well as lysis buffer for cell lysis to obtain DNA, whereas microwave-assisted digestion proved to be very rapid, with an incubation time of 2 min instead of 24 h at an incubator shaker without using lysis buffer. The correction of isolated DNA was detected using real-time PCR with melt curve analysis, which was 82.8 +/- 0.2 degrees C for highly repetitive cc-satellite gene region specific for human chromosome 17 (locus D17Z1). Consequently, microwave-based DNA digestion followed by silica column yielded a high-purity DNA with a concentration of 19.40 ng/mu l and proved to be a superior alternative to the phenol-chloroform method, presenting an environmentally friendly and efficient technique for DNA extraction. (C) 2015 Elsevier Inc. All rights reserved.
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    Supercritical CO2 processing of a chitosan-based scaffold: Can implantation of osteoblastic cells be enhanced?
    (Elsevier Science Bv, 2013) Ozdemir, Elif; Sendemir-Urkmez, Aylin; Yesil-Celiktas, Ozlem
    The effects of fabrication techniques were investigated for preparation of a chitosan based scaffold. A two-step process was used: fabrication of hydrogel which was subsequently processed either with supercritical CO2 (SC-CO2) or lyophilization. Various pressures from subcritical to supercritical (70, 160, 250 bar), temperatures (35, 45, 55 degrees C) and durations (2-3 h) were applied in order to elicit the optimum process parameters yielding the highest porosity which were determined as 250 bar, 45 degrees C, 2 h of processing at 5 g/min CO2 flow rate yielding a porosity of 87.03% which was similar to lyophilization (88.68%) achieved at 55 degrees C for 48 h. When osteosarcoma cells possessing cellular features of osteoblasts were seeded, SC-CO2 dried scaffold proved to be a more ideal support for cell attachment owing to the presence of both nano and micropores, thereby providing a more efficient and rapid alternative for tissue engineering applications. (c) 2013 Elsevier B.V. All rights reserved.