As mentioned above, the unsaturated fatty chains are
highly sensitive to oxidation reactions, their oxidation induced a
decrease in the rate of unsaturated fatty acids which will be converted
into saturated fatty acids or even into trans fatty acids. In
their studies, Jaswir et al. (2000a) found that the addition of rosemary,
sage extract and citric acid to the palm olein before frying
retard effectively the thermal oxidation of the unsaturated fatty
acids thus reducing the increase of saturated fatty acid especially
the palmitic acid.