Polyunsaturated fatty acids PUFAs oxidative deterioration

It is now widely appreciated that polyunsaturated fatty acids (PUFAs) are highly susceptible to oxidative damage. Indeed, the process of lipid peroxidation was broadly defined as the oxidative deterioration of polyunsaturated lipids by Tappel (1979). The presence of a double... 

Lipid peroxidation is a free radical-mediated, chain reaction resulting in the oxidative deterioration of polyunsaturated fatty acids (PUFAs) defined for this purpose as fatty acids that contain more than two double covalent carbon-carbon bonds. Singlet oxygen can produce lipid hydroperoxides in unsaturated lipids by non-radical processes (Pryor and Castle, 1984), but the reaction usually requires a radical mechanism (Porter, 1984). Polyunsaturated fatty acids are particularly susceptible to attack by free radicals. Lipid peroxidation is a complex process, and three distinct phases are recognized (a) initiation, (b) propagation and (c) termination (see Fig. 2.10). 

Lipid oxidation is a major cause of deterioration of quality in products containing unsaturated fats and oils, as they are highly sensitive to oxidation. Even a small amount of lipid oxidation products can cause a significant reduction in sensory quality and can have negative physiological effects. This poses restrictions on the formulation of foods containing nutritionally important lipids such as polyunsaturated fatty acids (PUFAs), which are... 

Fatty Acid Composition. Fatty acids are made up of hydrocarbon chains that contain an organic acid (COOH) grouping at one end. The backbone of the chain consists of carbon atoms connected by either single (saturated) or double (unsaturated) linkages (valence bonds). Saturated linkages are more stable than unsaturated linkages because the latter have the ability to combine readily with oxygen or other substances. Furthermore, fatty acids which contain two or more unsaturated bonds per molecule (polyunsaturated fatty acids or PUFA) are prone to rancidity (oxidative deterioration). 

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