Analysis of conjugated octadecatrienoic acids inmomordica balsamina seed oil by GLC and13C NMR Spectroscopy

Separation of conjugated octadecatrienoic acids by open tubular gas liquid chromatography (GLC) was performed using glass capillary columns coated with Carbowax 20 M and with OV‐1. The equivalent chain length of geometrical isomers of the conjugated octadecatrienoic acids belonging to the two series C18:3Δ8.10.12 and C18:3Δ9.11.13 were determined. The application of these results to the study of theMomordica balsamina seed oil shows that this oil contains two conjugated octadecatrienoic fatty acids in appreciable amounts, punicic acid (50%) and α‐eleostearic acid (13%). The isomerization of conjugated acids inM. balsamina seed oil was followed for one year. Quantitation of octadecatrienoic acids using GLC gave results similar to those obtained with13C NMR.