`The 'Peroxide Value' of Olive Oil - Olive Oil Times

The 'Peroxide Value' of Olive Oil

Jun. 19, 2013

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The per­ox­ide index, mea­sured in mil­liequiv­a­lents of active oxy­gen per kilo­gram, deter­mines the ini­tial oxi­da­tion of an oil in a qual­ity analy­sis.

As occurs with other fats, olive oil becomes oxi­dized when it comes into con­tact with the air. This is due to the fact that the unsat­u­rated fatty acids (monoun­sat­u­rated and polyun­sat­u­rated) have one or more dou­ble links, that take oxy­gen and give rise to the for­ma­tion of per­ox­ides, one of the main prod­ucts of oxi­da­tion.

On react­ing with another unsat­u­rated fatty acid, these per­ox­ides trans­form into hydroper­ox­ides which, in turn, are oxi­dated and give rise to the alde­hy­des and ketones that are respon­si­ble in this case for the ran­cid­ity of olive oils.

The per­ox­ide index indi­cates the qual­ity of life attrib­uted to a vir­gin olive oil from the moment it was pro­duced to when it was pack­aged.

Among the refined oils this para­me­ter is not indica­tive of any­thing, given that dur­ing the refine­ment process any prod­uct result­ing from oxi­da­tion is elim­i­nated and, there­fore, so is any trait indica­tive of its age.


Oxidation is an inevitable, nat­ural process. However, it appears later on among the vir­gin oils that present a high per­cent­age of oleic acid and a high polyphe­nol con­tent (nat­ural antiox­i­dants).

It is pos­si­ble to delay oxi­da­tion by stor­ing olive oils in a cool and dark place.

Olivarama arti­cles are unedited by Olive Oil Times.


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