No abstract

Despite the carcinogenic properties of some PAHs, and although edible oils are particularly prone to PAH contamination, no international legal limits for PAH in edible oils have been yet established. However, a number of methods for such analyses have been published, most of which are time consuming and unsuitable for routine analysis, as they do not permit analysis of a large number of samples per day. Since sample preparation is the most time‐consuming part of analysis, research to find fast sample preparation methods is of topical interest. In this paper, solid phase extraction with silica cartridges is applied as sole sample preparation step. A 250‐mg sample of oil in n‐hexane is loaded onto a 5 g silica cartridge and the PAH fraction is eluted with 8 mL of n‐hexane/dichloromethane 70/30. After solvent evaporation, the volume was adjusted to 100 μL and injected into a HPLC equipped with a C18 reverse phase column and a spectrofluorometric detector. Results show a relatively low recovery for the more volatile PAHs (Na and Ac) and good recovery for heavy PAHs. Repeatability is quite satisfactory, as coefficients of variation range between 5.0 and 13.0%.

No abstract

The application of the Arrhenius equation for the prediction of oxidative reaction rate in frozen foods is often precluded because of deviations from linearity. The latter are mainly caused by the occurrence of phase transitions of crystallizing components (that is, water, lipids, sugar). The aim of the present research was to study the temperature dependence of the lipid oxidation rate as affected by its physical state. To this purpose, the physical state and the oxidation rate of sunflower oil was evaluated from -30°C to 60°C. In this temperature range, sunflower oil presents different solid-liquid ratios because of the crystallization phenomena. A mathematical model accounting for both temperature and physical state was proposed to describe the kinetics of oxidation in the entire temperature range considered.