“Estudio de la estabilidad de aceites en procesos de fritura”Frying importance in the current Spanish diet is due to its extended use as both in the familiar scope and in small and large restoration establishments. This is the reason why it is important to have knowledge about the stability of oils used in this frying, as well as their nourishing quality.
An extensive bibliographic revision on about this subject has been done and the existence of some works about the stability of high oleic sunflower oil has been proved, but none have been found on frying with pomace olive oil. The results of this revision indicate that the appropriate analysis for studying the oxidative stability in oils are the following: acidity grade, peroxide value, extinction coefficients, polar compounds, stability with Rancimat method and fatty acids composition.The purpose of this Degree Final Work is to study, analyze and determine the stability of two commercial oils at frying temperatures (high oleic sunflower oil and pomace olive oil) and compare them, as well as prepare polar compound determination. To demonstrate this, 40 fryings were done with both oils in 2-litre-capacity frying equipment, at 180º C for 4 minutes, using commercial pre-fried frozen potatoes as product to be fried.
It was checked that with regard to the formation of polar compounds, the only parameter by law to discard a frying oil, both oils have similar behaviour, because at frying 40 the high oleic sunflower oil had 19,90% and pomace olive oil had 22.43% of polar compounds. Neither reached the limit value of 25%.The fatty acids evolution and acidity grade are very similar in both oils, while extinction coeficients, peroxide value and the stability with Rancimat method indicate that pomace olive oil oxidizes to a lesser extent, althought both show a good oxidative stability.
Key-words: frying, high oleic sunflower oil, oil oxidation, polar compounds, pomace olive oil.