Oxidative stability of lipids

The oxidative stability of lipids depends on several factors, including the degree of unsaturation, nature of unsaturation (position of double bonds), antioxidant content (tocopherols and synthetic antioxidants), prooxidant content (trace metals and enzymes), and storage conditions (exposure to heat, light, oxygen, and moisture). 

Angsupanich and Ledward (1998) showed that oxidative stability of lipids in Atlantic cod (Gadus morhud) muscle decreased after treatment at a pressure higher than 400 MPa dne to the release of metal ions from complexes. Of the major muscle proteins, myosin denatured at 100-200 MPa, whereas actin and most sarcoplasmic proteins denatured at 300 MPa. High-pressure treated hsh was harder, chewier, and gummier than both the raw and cooked prodncts. 

Granelli, K. 1996. The oxidative stability of lipids in milk and milk powder in relation to some pro- and antioxidants. Doctoral thesis, Swedish University of Agricultural Sciences, Uppsala, 1-82. 

Lu, F. S. H., Nielsen, N. S., Timm-Heinrich, M., and Jacobsen, C. (2011). Oxidation stability of marine phospholipids in the liposomal form and their applications. Lipids 46, 3-23. 

Milk contains trace amounts of SOD which has been isolated and characterized it appears to be identical to the bovine erythrocyte enzyme. SOD inhibits lipid oxidation in model systems. The level of SOD in milk parallels that of XO (but at a lower level), suggesting that SOD may be excreted in milk in an attempt to offset the pro-oxidant effect of XO. However, the level of SOD in milk is probably insufficient to explain observed differences in the oxidative stability of milk. The possibility of using exogenous SOD to retard or inhibit lipid oxidation in dairy products has been considered. 

Gertz, C. Klostermann, S. Kochhar, S.P. 2000. Testing and comparing oxidative stability of vegetable oils and fats at frying temperature. Eur. J. Lipid Sci. Tech. 102 543-551. 

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). 

The quality changes, such as lipid oxidation and reduction of tocopherols and phytosteols during neutralization, are considerable compared with the other processing steps as shown by Wang and Johnson (174), and also as presented in Table 12. The further phospholipid removal (below 2 ppm phosphorus) also reduces the oxidative stability of soybean oil (175) due to the antioxidant property of these phospholipids. 

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