Peroxide Value (PV)
Lipid oxidation involves the continuous formation of
hydroperoxides as primary oxidation products that may break down to a variety
of nonvolatile and volatile secondary products. The formation rate of
hydroperoxides outweighs their rate of decomposition during the initial stage
of oxidation, and this becomes reversed at later stages. Therefore, the
peroxide value (PV) is an indicator of the initial stages of oxidative change. However, one can assess whether a lipid is in the growth or decay portion
of the hydroperoxide concentration by monitoring the amount of hydroperoxides
as a function of time.
Analytical methods for measuring hydroperoxides in fats and
oils can be classi-fied as those determining the total amount of hydroperoxides
and those based on chromatographic techniques giving detailed information on
the structure and the amount of specific hydroperoxides present in a certain
oil sample. The PV represents the total hydroperoxide content and is one of the
most common quality indicators of fats and oils during production and storage.
A number of methods have been developed for determination of PV, among which
the iodometric titration, ferric ion complex measurement spectrophotometry, and
infrared spectroscopy are most frequently used.
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