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    Application of multivariate chemometric techniques for simultaneous determination of five parameters of cottonseed oil by single bounce attenuated total reflectance Fourier transform infrared spectroscopy
    (Elsevier, 2014) Talpur, M. Younis; Kara, Huseyin; Sherazi, S. T. H.; Ayyildiz, H. Filiz; Topkafa, Mustafa; Arslan, Fatma Nur; Naz, Saba
    Single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy in conjunction with chemometrics was used for accurate determination of free fatty acid (FFA), peroxide value (PV), iodine value (IV), conjugated diene (CD) and conjugated triene (CT) of cottonseed oil (CSO) during potato chips frying. Partial least square (PLS), stepwise multiple linear regression (SMLR), principal component regression (PCR) and simple Beer's law (SBL) were applied to develop the calibrations for simultaneous evaluation of five stated parameters of cottonseed oil (CSO) during frying of French frozen potato chips at 170 degrees C. Good regression coefficients (R-2) were achieved for FFA, PV, IV, CD and CT with value of > 0.992 by PLS, SMLR, PCR, and SBL. Root mean square error of prediction (RMSEP) was found to be less than 1.95% for all determinations. Result of the study indicated that SB-ATR FTIR in combination with multivariate chemometrics could be used for accurate and simultaneous determination of different parameters during the frying process without using any toxic organic solvent. (C) 2014 Elsevier B.V. All rights reserved.
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    A Highly Efficient Automated Flow Injection Method for Rapid Determination of Free Fatty Acid Content in Corn Oils
    (Springer, 2014) Ayyildiz, H. Filiz; Kara, Huseyin
    In the present study, a new flow injection (FI) methodology for determination of free fatty acid (FFA) content in corn oil samples is proposed. The proposed method is based on monitoring the absorbance changes at 580 nm, lambda (max), as a result of neutralization of FFA in oil samples by KOH in the reagent. The analyses were performed with a single-line FI manifold system created by modification of high performance liquid chromatography. The main parameters, such as sample and reagent volumes, reaction coil, reagent concentration and temperature were all optimized. With the newly developed sampling strategy, the oil sample and reagent at micro level were directly injected together without any pre-treatment. The proposed flow injection analysis method was validated statistically and it was found to be linear (between 0.09 and 1.50 FFA %), accurate (recovery 87.19-122.22 %), and precise (relative standard deviation < 1 % for both intra-day and inter-day precision). The limit of detection and limit of quantification were found to be 7.41 x 10(-3) and 2.24 x 10(-2) oleic acid %, respectively. The results were also compared with those obtained by the American Oil Chemists Society (Ca-5a-40) method using statistical t and F tests, and a significant difference was not observed between the methods at the 95 % confidence level. These results strongly suggest that this method is suitable for automated routine analysis of FFA in edible oils due to its simplicity, reliability, speed, and economy of solvents and sample.