Evaluation of the oxidative stability of oils using dielectric measurements and thermal analysis. Comparison with peroxide value.

MAZZOBRE, MARÍA FLORENCIA; TERPINC, PETRA; ABRAMOVIC, HELENA; EGATIN, NATAA; ABRAM, VERÓNIKA; BUERA, MARÍA DEL P.

Buenos Aires

Congreso; XIII Congreso Argentino de Ciencia y Tecnología de los alimentos CYTAL; 2011

The aim of this work was to study alternative methods such as dielectric measurements and thermal analysis to evaluate the oxidative stability of different edible oils in relation to standard chemical analysis. Thermal stability was evaluated by determining the dielectric constant, the peroxide value by tritration (PV) and the oxidation onset temperature by differential scanning calorimetry. Oils without heat treatment had a PV between 0.5 and 4 mmol O2/kg. PV ​​increased significantly in all samples with increasing time of thermal treatment. Chia, canola and rosehip oils were the most affected by heating, sunflower and olive were the most stable. The susceptibility of these oils to oxidation was related to their fatty acid content. Dielectric constant values ​​of the different oils increased during the oxidation process and correlated with PV measurements. The oxidation onset temperatures were lower in the oils with higher content of unsaturated fatty acids and decreased with time of heat treatment. Both the dielectric measurements and thermal analysis resulted adequate to evaluate the thermal stability of oils, with the advantage of the simplicity of these techniques and reduction in analysis time.