Possibilities of Application of NIR Technique in the Analysis of oilseeds and their Derivatives ‐ Examination of Used Frying Oils

Abstract

During deep fat frying process, several compounds arise in the oil. The determination of their quantity by the classical methods is a very long and laborious work. For this purpose, quick instrumental examinations are needed. Therefore, the authors have investigated the possibilities of applicability of the NIR technique for determining the polar, polymer and linoleic acid contents of the sunflower oil heated at 170-18O0 C and 200-210O C, resp., for different times. They examined the equation forms describing the relationship between the parameters and values measured at given wavelengths of the NIRspectra, the characteristic wavelengths, the Kvalues and the accuracy of the determination.They established that the NIR technique can give successful results by the quick determination of the examined parameters. It was found that the standard error of calibration (SEC) of polar content at a thermal load of 170-180O C was 0.991"/n and at that of 200-21O0C 0.9150/0, that for polymer content 1.21"/0 and 1.65"/0, resp., that for linoleic acid content 0.436'b and 0.446 "Yo,resp., and the multiple correlation coefficient was ranging between 0.994 and 0.999.

Quality Alterations of Four Frying Fats During Long‐term Heating (Conventional Analysis and Nirs Calibration)

“…Because excessive background often exists within the NIR spectra, multiplicative scatter correction (MSC) was applied during quantitative calibrations (Geladi et al 1985). The sloping background was removed by second derivative (2) of the spectra (Tahboub and Pardue 1985;El-Rafey et al 1988). A gap (8 nm) and a smoothing interval (6 nm) were used to reduce the noise, sample-to-sample baseline variation and to enhance the absorption peaks ("conventional WinISI format": 2,8,6).…”

“…1985). The sloping background was removed by second derivative (2) of the spectra (Tahboub and Pardue 1985; El‐Rafey et al. 1988).…”

Application of near infrared spectroscopy (NIRS) in the analysis of frying fats

“…On the other hand NIR-spectrometric analysis for testing food and used deep-frying fats may also have a profound effect reducing analytical effort for time, chemicals and laboratory instruments [1][2][3][4][5][6][7]. The values of several parameters can be calculated from only one spectrum.…”

NIR based quality control of frying fat samples by means of Polar Qualification System

“…In contrast to traditional chemical analysis, no reagents are required and no waste is produced (Uddin & Okazaki, 2004). For investigating frying fats, several papers discussed its applicability (Büning-Pfaue & Kehraus, 2001;El-Rafey, Peredi, Kaffka, Náday, & Balogh, 1988). Cho, Kim, and Rhee (1998) tested NIR spectroscopy in the estimation of rancidity.…”