Browsing by Author "Temel Kan BAKIR"

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Investigation of Oxidation Rate Relationship Between Fatty Acid Contents of St. John’s Wort (Hypericum perforatum) Oil and Nettle (Urtica dioica) Seed Oil
(2018-06-01) Temel Kan BAKIR
Vegetable extract oils are now widely used in health, cosmetics and food fields. Theoxidation rates of these industrial oils are closely related to their chemical composition. Inthis study, fatty acid contents of St. John’s Wort (Hypericum perforatum) oil and Nettleseed (Urtica dioica) oil were investigated by gas chromatography (GS-MS) and theeffects on lipid peroxidation time were tried to be related. The peroxidation of oilemulsions was carried out at in a ventilated incubation environment 37°C and pH 7.Pseudo first order constants of primer oxidation products (hydroperoxides) werecalculated by Fe (III) SCN method and they found for St. John’s Wort oil and Nettle seedoil, (2.05±0.23)×10-1 and (6.64±0.54)×10-1 hour-1,respectively. This study was conductedby showed that the oxidation rates of St. John’s Wort and Nettle seed oils are closelyrelated to the chemical composition as well as the saturation ratings of fatty acids.
Synthesis, spectroscopic studies, and antioxidant activities of novel thio/carbohydrazones and bis-isatin derivatives from terephthalaldehyde
(2020-02-01) Hasan YAKAN; Temel Kan BAKIR; Halit MUĞLU
New bis(isatins-thio/carbohydrazones) based on Schiff bases were prepared from terephthalaldehyde biscarbohydrazone and 5-substituted isatins in the presence of a drop of sulfuric acid under reflux in ethanol. Terephthalaldehyde bis(thio/carbohydrazone) was synthesized by the reaction of (thio)/carbohydrazide and terephthalaldehyde inthe presence of a few drops of acetic acid under reflux in ethanol. The structures of these synthesized compounds weredetermined using IR, 1 H NMR, and 13 C NMR spectroscopy and elemental analysis. The in vitro antioxidant activityof all the compounds was determined by the 1,1-diphenyl-2-picryl hydrazyl (DPPH.) free radical scavenging method.Compound 2 showed the best antioxidant activity.
The investigation of the effect of freezing pretreatment on properties of black garlic produced from Kastamonu garlic
(2020-10-01) Bahar NAZLI; Fatma KANDEMİRLİ; Nesrin İÇLİ; Temel Kan BAKIR; Serap AYDIN
Black garlic is obtained by fermentation of fresh garlic in condition under controlled high humidityand temperature.The aim of this study is to investigate the effect of freezing as pre-treatment process on black garlic produced from fresh Kastamonu garlics in terms of various antioxidant activityparameters, phenolic and flavanoid contents, fermentation time and HMF formation. The antioxidant properties analysis results of frozen and non-frozen black garlic samples were shown thathigher than those of white garlic and it was observed that total antioxidant capacity, the total phenolic compound and total flavanaoid content values of black garlics increase with the storage period under fermentation conditions. In addition, frozen garlics were found to have higher totalantioxidant activities on the 25th and 30th days (9.56 mg AE/g and 10.40 mg AE/g, respectively)of the fermentation than the activities of non-frozen garlics the on the 35th day (8.49 mg AE/g) offermentation. The toxic compound HMF formation was found of the frozen sample at as high as110 mg/kg in end of the 35th day. In conclusion, the use of pre-frozen garlics in black garlic production will be more efficient in respect of antioxidant properties and time and cost saving