Determination Of Lipid Contents Of Two New Soy Bean Cultivars Using Gas Chromatography – Mass Spectrometry (GC-MS)

Abstract

Determination of fatty acids and sterols in oil is very important as they serve as the vital indicators of the activity and purity, respectively of the oils. A qualitative Gas Chromatography – Mass Spectrometry study of oils from soy beans of two varieties (TGX 1802-1F, and TGX 1019-2EB) was done to determine their fatty acid, sterol and other compositions. The oils were extracted with n-hexane and concentrated in vacuo using rotary evaporator at 45 oC. The oils were slightly soluble in ethanol, insoluble in water and acetonitrile, and readily soluble in n-hexane, acetone, chloroform and benzene. The oils were preliminarily characterized using iodine value, acid value, specific gravity, volatile matter, saponification value and peroxide value. The acid values were 0.60 and 0.59 respectively, while the specific gravity at 30 oC was 0.919 for both samples. The volatile matters were 0.19 % and 0.17 %, and the peroxide
values were 9.2 and 9.8 mEq/Kg respectively. Using an Agilient series 6890 Gas Chromatography system with a 5973 mass selective detector, the lipid composition of these oils was studied. Both cultivars were found to contain linoleic acid and pentadecadienoyl octadecadienoate. Palmitic acid and stearic acid were found in TGX 1802-1F, while TGX 1019-2EB was found to contain cholesterol and methyl octadecadienoate. This implies that TGX 1802-1F will be safe in applications where cholesterol free oils are desired. Also, the presence of linoleic acid in the oils indicate that they may be suitable as supplements for lowering the LDL cholesterol levels of the body as well as serve, via Gamma Linolenic Acid, in the biosynthesis of the very important anti – inflammatory 1 – series prostaglandins.