Cyclopropenoid fatty esters

Cottonseed oil also contains cyclopropenoid fatty esters that are toxic and block the enzymatic conversion of stearic to oleic add. These cyclo-propenoids are essentially inactivated by heat during deodorization (Eaves et al., 1968 White, 1992). 

Figure 5.8 Mass spectra (70 eV) of dimethyloxazoline derivatives of A, 9,10-methyleneocta-dec-9-enoic (sterculic) acid B, 2-hydroxy-sterculic acid. Redrawn from Spitzer, V., GC-MS characterization (chemical ionization and electron impact modes) of the methyl esters and oxazoline derivatives of cyclopropenoid fatty acids, J. Am. Oil Chem. Soc., 68(12), 963-9,1991.

Cyclopropenoid fatty acids (methyl ester derivatives) are rather labile and not easily subjeded to GC (see Chapter 5). Nonetheless, mass spedra of the methyl ester derivatives of some naturally occurring fatty acids of this kind have been published [698]. These are rather different from the spedra of most other unsaturated esters, but it is doubtful whether they would assist greatly in the identification of an unknown. One of the most popular methods for the analysis of cyclopropenoid fatty acids involves GC of the methoxy- and keto-derivatives formed by readion... 

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