Measurement of lipid oxidation

In addition to organoleptic assessment, several chemical/physical methods have been developed to measure lipid oxidation. These include peroxide value, thiobarbituric acid (TBA) value, ultraviolet absorption (at 233 nm), ferric thiocyanate, Kreis test, chemiluminescence, oxygen uptake and analysis of carbonyls by HPLC (see Rossell, 1986). 

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Kwon, T.-W. and Watts, B.M. 1964. Malonaldehyde in aqueous solution and its role as a measure of lipid oxidation in foods. J. Food Sci. 29 294-302. 

The headspace oxygen method is simple and reproducible and may be the best analytical method to evaluate the oxidative stability of fats and oils (14). Its application in measurement of lipid oxidation in food products other than fats and oils, however, is limited because protein oxidation also absorbs oxygen (15). 

Peroxide value. Peroxide value (PV) is the most common measurement of lipid oxidation. Hydroperoxides have no flavor or odor of their own, but they are unstable and break down rapidly to other products such as aldehydes that have a strong, disagreeable flavor and odor. Peroxide value measures the mUiequivalents of oxygen... 

Peroxide value (P V) is the most commonly used measurement of lipid oxidation. The standard iodometric method requires a relatively large sample (5 g) when the lipid is only slightly oxidized. The ferric thiocyanate method, based on the oxidation of ferrous to ferric ion, involves colorimetric measurement of ferric thiocyanate. This method is more sensitive than the iodometric method and requires a relatively small sample (0.1 g). The PV is a useful measure for samples with low levels of oxidation and when the hydroperoxides are not decomposed. During prolonged oxidation, a maximum PV is reached and the value then begins to decrease due to peroxide degradation. This maximum value occurs early for soybean and rapeseed oil, due to the more rapid decomposition of the hydroperoxides of the polyunsaturated fatty acids. 

Many methods have been developed to access the extent of oxidative deterioration, which are related to the measurement of the concentration of primary or secondary oxidation products or of both. The most commonly used are peroxide value (PV) that measures volumetrically the concentration of hydroperoxides, anisidine value (AV), spectrophotometric measurement in the UV region and gas chromatographic (GC) analysis for volatile compounds. Vibrational spectroscopy, because of its high content in molecular structure information, has also been considered to be useful for the fast measurement of lipid oxidation. In contrast to the time consuming chromatographic methods, modem techniques of IR and Raman spectrometry are rapid and do not require any sample preparation steps prior to analysis. These techniques have been used to monitor oil oxidation under moderate and accelerated conditions and the major band changes have been interpreted. ... 

Gray, J.I. and Monahan, F.J. Measurement of lipid oxidation in meat and meat products. Trends Food Sci. Technol. 3, 315-319 (1992). 

Nielsen, H.K., Loliger, J. and Hurrell, R.F. Reactions of proteins with oxidizing lipids. 1. Analytical measurements of lipid oxidation and of amino acid losses in a whey protein-methyl linolenate model system. British J. Nutr. 53, 61-73 (1985). 

Although canola oil contains a high level of OA, it also contains a relatively high level of LNA and thus the potential to increase oxidative stress in vivo. Oxidized LDL (ox-LDL) plays a fundamental role in the development of atherosclerosis. High PUFA intakes were found to promote the formation of ox-LDL whereas LPT, enriched with OA were stabler to oxidation. In vitro-conjugated diene formation (a measure of lipid oxidation) of the LDL fraction of snbjects fed diets, where canola oil or high... 

F Boukobza, PJ Dunphy, AJ Taylor. Measurement of lipid oxidation-derived volatiles in fresh tomatoes. Postharvest Biol Technol 23 117-131, 2001. 

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