Assessment of oxidation in heated safflower oil by physical, chemical and spectroscopic methods.

Saflower oil was heated at 180C by static heating in an open pan or in an oven,
or by heating through intermittent heating-cooling cycles (as in &ins) over a
period of 8 h. The extent of deterioration of the oil was followed by measurement
of physical characteristics such as color and viscosity and the chemical indices
such as fiee fatty acid, peroxide, iodine, conjugated diene and triene values,
unsaponijiable matter and oxidized fatty acids. The extent of oxidation was also
assessed by inpared (IR) and nuclear magnetic resonance (NMR) spectroscopic
techniques through analysis of oxidized fatty acids. The results indicated that
heating in open pan caused deterioration in oil faster than in other treatments.
Furthermore, the IR, and NMR studies of the oil heated in an open pan indicated
cross polymerization while during oven heating andhing cross polymerization
was not observed