Cyclic fatty acids formed in heated vegetable oils

By using linseed oil and high-oleic and normal sunflower oils as models, only recently have researchers elucidated the complete CFAM structures from the three unsaturated precursors, as described in the following section. It is apparent that a complete analysis of CFAMs in a heated oil or in a fried food is a far from routine task and involves detailed study. The methods available for quantification of CFAMs are often multistep and do not always give satisfactory results, although continuous improvements have been made over many years. This aspect is considered in Section 5.3.2. 

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Dobson, G., W.W. Christie, and J.-L. Sehedio, The Nature of Cyclic Fatty Acids Formed in Heated Vegetable Oils, Grasas Aceites 4 26-33 (1996). 

Figure 5.13 Carbon atoms involved in cyclization of A, a-linolenic acid B, linoleic acid C, oleic acid. Redrawn from Dobson, G., Christie, W. W. and Sebedio, J.-L., The nature of cyclic fatty acids formed in heated vegetable oils, Grasas y Aceites, 4, 26-33, 1996.

The analysis of cyclopropane acids was reviewed by Minnikin (1978) and by Christie (1970), who also covered cyclopropene acids. Subsequently, Sebedio and Grandgirard (1989) discussed naturally occuring cyclic acids and cyclic acids formed in heated vegetable oils. Cyclic acids were the subject of a recent review (Le Quere and Sebedio, 1996). Useful information on gas chromatography (GC), mass spectrometry (MS) and high-pressure liquid chromatography (HPLC) of cyclic fatty acids can be found in books by Christie (1987, 1989). In the present chapter the aim is to concentrate on the more recent literature and those publications considered to be particularly... 

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