Kinetics of malonaldehyde content in enriched chicken meat during isothermal cooking

Effects of temperature and ferric ion on the formation of glycerol core aldehydes during simulated frying

Glycerol core aldehydes (GCAs) are toxins widely formed in oils at high temperature. This study investigated the effects of frying time, temperature, and Fe³⁺ content on the GCAs formation in high-oleic sunflower oil. The results showed that the GCAs (8-oxo, 9-oxo, 10-oxo-8, 11-oxo-9) concentrations increased with time following the pseudo-first-order kinetics. Frying at 160 °C without Fe³⁺ and at 180 °C with 0.0005 mol·L^-1 Fe³⁺ yielded the lowest and highest total GCA content. The concentrations of GCAs (8-oxo) and GCAs (9-oxo) or GCAs (10-oxo-8) and GCAs (11-oxo-9) changed similarly with different frying temperature and Fe³⁺ concentration. The major GCAs was GCAs (9-oxo) (40-70%), which also had the highest formation rate (5.42 × 10^-4 mg·g^-1·h^-1). However, GCA (10-oxo-8) and GCAs (11-oxo-9) with similar proportion (ca. 10-20%) and GCAs (8-oxo) made up the least proportions (<10%).

Kinetic modeling of malondialdehyde reactivity in oil to simulate actual malondialdehyde formation upon lipid oxidation

The reactivity of malondialdehyde in saturated glycerol triheptanoate oil was studied over a wide temperature range (298.15-453.15 K). With respect to the non-ideal character of a lipid medium, a kinetic model was proposed that described the experimental malondialdehyde data by a reversible hydrolytic cleavage and an irreversible aldol self-condensation reaction. Significant parameter estimates were obtained by using a global one-step non-linear regression procedure. The aldol self-condensation of malondialdehyde showed to be the main degradation route of malondialdehyde in oils. Simulation of the malondialdehyde formation during lipid oxidation of sunflower oil demonstrated that, depending on the heating time, the experimentally obtained malondialdehyde concentrations can substantially underestimate the ongoing lipid oxidation.