ESSENTIAL FATTY ACID-DEFICIENT RATS .2. ON FATTY ACID COMPOSITION OF PARTIALLY HYDROGENATED ARACHIS, SOYBEAN AND HERRING OILS AND OF NORMAL, REFINED ARACHIS OIL

The fatty acid composition of partially hydrogenated arachis (HAO), partially hydrogenated soybean (HSO) and partially hydrogenated herring (HHO) oils and of a normal, refined arachis oil (AO) was studied in detail by means of direct gas liquid chromatography, ultraviolet and infrared spectrophotometry and by thin layer chromatography fractionation on silver nitrate-silica gel plates followed by gas liquid chromatography. It was shown that the partially hydrogenated oils all contained fatty acids with trans double bonds. In the plant oils, the trans acids were present mainly as elaidic acid. The HHO showed an almost equal distribution between trans 18:1 ω9, trans 20:1 ω>9 and trans 22:1 ω>9. Some trans configuration was also found in the C20-and C22-dienes and trienes of the HHO. In all the oils, conjugated fatty acids were present in minor amounts only (<0.5%). Special attention was given to the ω-acids known to be of specific nutritional value. The HSO contained about 32% linoleic acid, whereas the content of cis, trans+trans, cis and trans, trans octadecadienoic isomers was 1.7% and 0.5%, respectively. The amount of linoleic acid in the HSO was even higher than that of AO (29%). The HAO contained only 0.8% 18:2 ω6 (linoleic acid). Further, two 18:2 fatty acids with ω>6, a cis, cis and a trans, trans isomer, were present in small amounts. The HHO contained 0.5% 18:2 ω6 (linoleic acid). Isomers of 18:2 ω>6 were also found in the HHO. They may be hydrogenation products of higher unsaturated C18-acids orginally present. All the C20- and C22-dienes and trienes were shown to have an ω-chain greater than 6. Fatty acids with ω6-structure were not formed during partial hydrogenation of the oils studied. © 1969 The American Oil Chemists' Society.