Volatile Products of Edible Oils by Open Air Heating. I.

Abstract

The components of the volatile decomposition products of soybean oil by thermal oxidation were studied at different stages of deterioration.Soybean oil was previously heated at 240°C for 2, 4, 6 and 10 hr, respectively, and was differentiated according to changes in their chemical properties or degree in deterioration. The Soybean oils thus differentiated were then heated at 240°C under stream of air for 1 hr, and the volatile decomposition products coming therefrom were collected in two traps cooled by ice-water and dryiceacetone for identification by gas chromatography.The gas-chromatograms showed that these decomposition products consist of many sorts of aldehydes and hydrocarbons, and that there were slight differences in the quantitative proportions of these compounds given off from soybean oils according with the varying degrees in deterioration. The contents of olefinic hydrocarbons and C4, C5, C6 aldehydes increased and pentane decreased in the volatile products from soybean oil at an advanced stage of thermal oxidation.It seemed that the differences in the quantitative proportions of the volatile products from soybean oils at different stages of thermal oxidation were related differences in the contents of linoleic and linolenic acids in these oils.