Fish oil oxidation

Fantoni, C.M., Cuccio, A.P. and Barrera-Arellano, D. (1996) Brazilian encapsulated fish oils Oxidative stability and fatty acid composition. J. Am. Oil Chem. Soc., 73, 251-253. 

The volatiles derived from oils containing hnolenic acid (soybean and canola oils) have significant sensory impact and lower threshold values than the volatiles derived from oils containing linoleic acid (cottonseed, com and sunflower oils) (Table 5.1). The most sensory-significant linolenate-derived aldehydes (with lower threshold values) were characteristic in having n-3 unsaturation. These trends explain why linolenic acid oils develop undesirable odors and flavors at much lower levels of oxidation (peroxide value of less than 1) than linoleic acid oils (peroxide value of 10). Similarly, potent volatile aldehydes have been identified in fish oil oxidized at very low levels of oxidation by static and dynamic headspace GC (see F.2) and detected by GC-MS at parts per billion levels, including cw-4-heptenal (1250 ppb), fran, cw-2,6-nonadienal (1231 ppb)andCiXcw-3,6-nonadienal(627 ppb). Cis-4-heptenal is produced by decomposition of fran, cw-2,6-nonadienal, which can be produced in turn by the decomposition of n-7 and n-9 hydroperoxides derived from the oxidation of 20 4, 20 5 and 22 6 n-3 PUFA (Chapter 4, D4). 

Sekhon-Loodu, S., Wamakulasuriya, S. N., Rupasinghe, H. P. V. Shahidi, F. (2013). Antioxidant ability of fractionated apple peel phenolics to inhibit fish oil oxidation. Food Chemistry, 140, 189-196. 

JACOBSEN C, HARTVIGSEN K, THOMSEN M K, HANSEN L F, LUND P, SKIBSTED L H, H0LMER G, ADLER-NissEN J and MEYER A s (2001) Lipid oxidation in fish oil enriched mayonnaise calcimn disodium ethylenediaminetetraacetate, but not gallic acid, strongly inhibited oxidative deterioration, J Agric Food Chem, 49, 1009-19. 

K Heinzelmann, K Franke. Using freezing and drying techniques of emulsions for the microencapsulation of fish oil to improve oxidation stability. Colloids Surfaces B Biointerfaces 12(3—6) 223—229, 1999. 

Matsuo, N. (1962). Nutritional effects of oxidized and thermally polymerized fish oils. In "Lipids and Their Oxidation" (H. W. Schultz, E. A. Day, and R. O. Sinnhuber, Eds.),... 

Kagami, Y., Sugimura, S., Fujishima, N., Matsuda, K., Kometani, T., Matsumura, Y. (2003). Oxidative stability, structure, and physical characteristics of microcapsules formed by spray drying of fish oil with protein and dextrin wall materials. Journal of Food Science, 68, 2248-2255. 

Keogh, M.K., O Kennedy, B.T., Kelly, J., Auty, M.A., Kelly, P.M., Fureby, A., Haahr, A.-M. (2001). Stability to oxidation of spray-dried fish oil powder microencapsulated using milk ingredients. Journal of Food Science, 66, 217-224. 

If a soap is added to a lead hydrogen arsenate-hydrated ferric oxide mixture considerable damage and leaf drop is caused, especially if the soap contains a strong base, as in the case of commercial potash fish-oil soap or potassium oleate. Laboratory tests show that more soluble arsenic is formed than with a soap of a weak base such as triethanolamine oleate.7 The addition of cryolite to an arsenate inhibits the formation of soluble arsenic 8 fluosilicates cause decomposition. These fluorine... 

Normally, the method of choice for the analysis of complex mixtures of polyenoic fatty acids such as those derived from fish oils is capillary gas chromatography with prechromato-graphic derivatization and mass spectrometric detection. However, GC is impractical for the purification of the large amounts of polyenoic fatty acids required for biological and clinical studies. Moreover, the temperatures required in GC may cause degradation of oxidized long-chain polyunsaturated fatty acids that are present as minor components of the mixture. 

The safety of drugs containing EPA and DHA has been reviewed the reported adverse effects were similar to those in control groups (3). Even 3-7 g/day for several months did not change liver enzyme activities, and there were no bleeding problems. Consumption of fish oils reduces the resistance of LDL to oxidative modification, and this is partly opposed by the addition of vitamin E (4). Belching or eructation with a fishy taste or smell, vomiting, flatulence, diarrhea, and constipation are relatively common. 

Wander RC, Du SH, Ketchum SO, Rowe KE. Effects of interaction of RRR-alpha-tocopheryl acetate and fish oil on low-density-lipoprotein oxidation in postmenopausal women with and without hormone-replacement therapy. Am J Clin Nutr 1996 63(2) 184-93. 

The alkadienals could be formed from the autoxidation of PUFA and may contribute desirable arenas to freshly prepared foods (19). Further degradation of alkadienals often increased undesirable flavors. Josephson and Lindsay demonstrated that 2,4-decadienal could produce 2-octenal and ethanal (20) and 2,6-nonadienal could produce 4-heptenal and ethanal (21) via retro-aldol condensation mechanisms. Hsieh et al. (22) reported that iscmers of various alkadienals and alkatrienals gave green, greasy and oxidized fish oil odors in crude menhaden fish oil. 

Sethi, S., Inhibition of leukocyte-endothelial interactions by oxidized omega-3 fatty acids a novel mechanism for the anti-inflammatory effects of omega-3 fatty acids in fish oil, Redox Rep., 7, 369, 2002. 

Erdogan, H., Fadillioglu, E., Ozgocmen, S. etal., Effect of fish oil supplementation on plasma oxidant/antioxidant status in rats, Prostaglandins Leukot. Essent. Fatty Acids, 71, 149, 2004. 

Because of the toxic nature of these oxidized components, the authors cautioned regular intake of encapsulated fish oils. The sale of oxidized fish oil products can be considered criminal as they pose potential health risks to the consumer. In addition to ensuring that the consumer is buying the authentic product, it must be fresh, with a clear and realistic shelf-life date indicated. The presence of vegetable oils in a fish oil is best tested for by examination of the sterol composition, as fish oils consist almost entirely of cholesterol and 24-methyl cholesterol (Paganuzzi, 1983). Analysis of the sterol fraction of the oil can often identify the oil, or at least indicate which oils might be present. 

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