Changes in seed oils attributable to the refining processes

Abstract

The chemical composition of 2 peanut oils, 2 sunflower seed oils and maize oils in the unrefined and refined states was determined. The analyses covered acidity, I number, peroxide value, spectrophotometric characteristics and the fatty acid composition, with particular reference to the % palmitic and stearic acids in the 2 position. Additionally, the nonsaponifiable contents of the sterol fractions of these 6 oils and of 2 soybean, 2 rapeseed and 2 grape seed oils at 4 stages of refining (crude, neutralized, decolorized, deodorized) were also determined. All results are tabulated. A characteristic feature of the glyceride structure of the peanut, sunflower seed and maize oils was their almost complete lack of saturated fatty acids in the 2 position. The results of the analyses are considered to be a useful introduction to definition of the limits of variability of these acids in the 2 position. For all the oils examined, there was a decline in the content of nonsaponifiable components of the sterol fraction.