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Öğe A Chemometric Approach to Assess the Frying Stability of Cottonseed Oil Blends During Deep-Frying Process: I. Polar and Polymeric Compound Analyses(WILEY, 2013) Arslan, Fatma Nur; Kara, Huseyin; Ayyildiz, Hamide Filiz; Topkafa, Mustafa; Tarhan, Ismail; Kenar, AdnanThe main goal of the present study was (i) to determine the formation of degradation products in cottonseed oil (CSO) blends during deep frying process by adsorption and high performance size exclusion chromatography techniques and (ii) to evaluate the impacts of food additives on total polar (TPC) and polymeric compound (PTAG) formation using a chemometric approach. In order to prepare the frying CSO blends; ascorbic palmitate, mixed tocopherols, dimethylpolysiloxane, lecithin and sesame oils were used as additives. To determine the real impacts of additives, a quarter-fraction factorial experimental design with two levels and five factors was used. The changes in TPC and PTAG data were carefully evaluated during 10 h of frying at 170 +/- A 5 A degrees C with normal distribution (ND) graphs and analyzed using a one-way analysis of variance (ANOVA), followed by Tukey's Post-hoc test (alpha = 0.05). The results indicated that the increasing values for TPC and PTAG during the frying processes for all blends, TPC and PTAG contents reached maximum levels of 16.37 and 6.01 % respectively, which are below the limit values stated by official authorities for the quality assessment of frying oils. The ANOVA test results were in good agreement with ND graphs and data indicated that the impact of mixed tocopherols was significant for TPC formation, meanwhile the impact of lecithin and ascorbic palmitate x dimethylpolysiloxane were significant for PTAG formation. Thus, the present study should be considered to be a very useful guide for developing new frying oil formulations based on CSO by using food additives.Öğe A chemometric study: Automated flow injection analysis method for the quantitative determination of humic acid in Ilgm lignite(ELSEVIER SCIENCE BV, 2016) Tarhan, Ismail; Kara, HuseyinA rapid, sensitive and provident flow injection analysis (FIA) method was developed within the framework of a chemometric approach for the quantification of humic acid (HA) in the lignite obtained from Ilgm, Konya, Turkey. The proposed method allows automatic determination of 60 samples per hour over a wide calibration range (0-2000 mg L-1, R-2: 0.9988) and needs only 10 mu L of sample at a flow rate of mobile phase (X-1), 2 mL min(-1); pH of mobile phase (X-2), 8, and system temperature (X-3), 20 degrees C. The limits of detection (LOD) and quantification (LOQ) were calculated as 9.18 mg L-1 and 30.60 mg L-1, respectively, and the relative standard deviation (RSD) for 500 mg L-1 HA was calculated as 3.44 (n: 9). It was revealed that the standard deviation (SD) values of the proposed FIA method are lower than those of the spectrophotometric method. (C) 2014 King Saud University. Production and hosting by Elsevier B.V.Öğe A new HPLC method for simultaneous analysis of sterols, tocopherols, tocotrienols, and squalene in olive oil deodorizer distillates using a monolithic column with chemometric techniques(ROYAL SOC CHEMISTRY, 2019) Tarhan, Ismail; Kara, HuseyinIn this study, a simple, rapid, and special method was developed for the simultaneous quantification of sterols (campesterol, beta-sitosterol, and stigmasterol), tocotrienols (alpha, (beta + gamma), and delta), tocopherols (alpha, (beta + gamma), and delta), and squalene in an olive oil deodorizer distillate using monolithic-chromatographic systems with chemometric techniques. The chromatographic conditions which are the mobile phase polarity (P '), the flow rate (mL min(-1)) and the temperature of the column compartment (degrees C) were optimized by using three experimental calibration designs. The optimal chromatographic conditions obtained using a response surface methodology were as follows: the polarity of the mobile phase, 7.00, 6.00, 5.70, and 5.10 for sterols, tocotrienols, tocopherols, and squalene, respectively; the flow rate, 2.50 mL min(-1); the temperature of the column compartment, 38.41 degrees C; and detection, at 202 nm using a diode array detector. For calibrations of all of the bioactive compounds, correlation coefficient values (R-2) were obtained at high values close to one and the limit of detection and the limit of quantification were satisfactory. The monolithic column used had a low column pressure despite the high polarity and the high flow rate values of the mobile phases thanks to its porous structure and it made possible an efficient chromatographic separation.Öğe Quantitative determination of free fatty acids in extra virgin olive oils by multivariate methods and Fourier transform infrared spectroscopy considering different absorption modes(TAYLOR & FRANCIS INC, 2017) Tarhan, Ismail; Ismail, Ashraf A.; Kara, HuseyinA methodology based on Fourier transform infrared (FTIR) spectroscopy with different absorption modes, combined with chemometrics techniques, was developed as a tool to quantify the free fatty acids (FFAs) in extra virgin olive oils (EVOOs). The range of FFA contents of calibration samples was extended by adding 0-1.00% oleic acid to refined and deodorized olive oil (RDOO) containing 0.00% FFA. Calibration models were implemented using the partial least-squares (PLS) regression technique. Two absorption modes, reflection and transmission, and two pretreatments, normal and first derivative spectra, were tested in several infrared spectral regions. In order to construct the calibration models, 15 calibration samples were scanned in different absorption modes, and 10 different brands of EVOOs were used for checking the predictive capacity of the best calibration model. The results showed that the best predictions were achieved using normal spectra in the transmission mode using 100 mu m CaF2 flow cell with the highest correlation coefficient (R-2) of 0.99979 and the lowest root mean square error of calibration (RMSEC) of 0.00441 and root mean square error of cross-validation (RMSECV) of 0.0107 in the infrared spectral region 1724-1646 + 3324-3023 cm(-1). The method developed is fast, environment-friendly, and it could be easily used in olive oil industries for the rapid and reliable quantification of FFA content in EVOOs.Öğe Removal and Preconcentration of Cobalt Ions from Aqueous Media Using ImHA Packed Column by On-Line SPE System(SPRINGER INTERNATIONAL PUBLISHING AG, 2012) Ayyildiz, H. Filiz; Topkafa, Mustafa; Arslan, FatmaNur; Durmaz, Fatih; Kucukkolbasi, Semahat; Tarhan, Ismail; Kara, HuseyinThis work assesses the use of immobilized humic acid (ImHA) onto aminopropyl silica (APS) as a sorbent for the removal and preconcentration of trace amounts of cobalt ions by on-line solid phase extraction (SPE) technique in the column system prepared in our laboratory. Different parameters, such as the effect of the pH, concentration, and flow rate, were studied and throughput was observed by a UV detector. All SPE steps were monitored by breakthrough curves used to visualize distribution of cobalt concentration between mobile and solid phase. The solutions collected from stripping steps were analyzed in atomic absorption spectrometer (AAS) and the amount of sorbed ions was calculated. Sorption characteristics were evaluated by using common adsorption isotherms and Scatchard plot analysis. From the obtained results, it was seen that sorption mechanism of cobalt ions were fitted to Langmuir model on a large scale and thought to be localized. Mean free energy (E = 40.82 kJ mol(-1)) calculated from D-R isotherm showed that chemical interactions are more effective than physical interactions. This investigation reveals a new, simple, environmentally friendly, and cost-effective method for removal and preconcentration of cobalt ions from aqueous solutions by a new aminopropyl silica-immobilized humic acid material.
