Polyunsaturated versus saturated index as a reference for determining the quality of edible seed oils extracted from locally cultivated oil seeds of Ethiopia

Abstract

Consumption of edible oils is increasing tremendously regardless of their high prices. As a result, the global production of vegetable oils has also been growing constantly. This may be related to global population growth and associated increasing demands of the consumers. In this particular work, ten crude food seed oils of Ethiopian origin were extracted in our lab and analyzed for their chemical composition by gas chromatography mass spectroscopy (gc-ms). To check their food quality, P/S index of all laboratory extracted seed oils were compared. The fatty acids (fas) concentrations of the oils were determined using decanoic acid methyl ester as internal standard and linoleic acid ethyl ester as a reference. The analysis results indicate that the P/S index for standard crude oils were 8.19 for safflower (sff), 2.58 for sesame (ses), 4.37 for Niger (nig), 5.50 for Linseed (lns), 2.04 for peanut (pnt), 5.13 for Ethiopian mustard (etm) 4.25 for sunflower (suf), 0.09 for palm (pal), 3.14 for soybean (sob), and 1.56 for cotton (cot). The maximum and minimum P/S index were obtained for SFF oil (8.19) and pal oil (0.09), respectively. Analysis of the mixtures of commercial lns and pal oils indicate the improvement of the food quality of the pal seed oil by mixing them in an appropriate ratio.