Abstract
The component acids of four groundnut oils of differing iodine value (86 to 99) have been determined. The linoleic acid content of the mixed fatty acids varied from 20% to 38%, the oleic acid content correspondingly ranging from 60% to 39%. These variations are similar to those recorded by previous workers for groundnut oils, but their cause is not clear and varietal influences as well as conditions of growth of the fruit may play a part in the case of groundnuts.
The variable linoleic acid content has a marked influence on the component glycerides of the oils. Thus with only 20% of linoleic acid a groundnut oil contains linoleo groups in only about half of its glycerides and dilinoleoβglycerides occur only in small proportions; but in oils of high linoleic content about 90% of the glycerides may contain linoleo groups (20% of the oil being made up of dilinoleoβglycerides). Moreover, triunsaturated glycerides in the first case contain very little oleodilinolein, but the latter forms about half of the triunsaturated glycerides of groundnut oils with 35β40% of linoleic acid.
The probable bearing of these factors on liability to oxidative rancidity is considered. Attention to the composition of seed oils intended for specific technical uses, as a primary consideration in the selection of oilseeds for cultivation, is indicated.