Comparative Assessment of Physicochemical Properties of locally and mechanically Produced Groundnut (Arachis hypogaea) Oil Stored Over a Period of Time.

Abstract

Groundnut oil was extracted using both local and mechanical methods of extraction. 5litres of each of the oil samples were measured into a plastic gallon and kept in a cool and dry place (average temperature of 28OC). The effect of extraction method and Period of storage were examined. The oil samples from both methods of extractions were analyzed for physicochemical and proximate composition at fresh state and subsequently during storage, using standard methods. The result revealed that free fatty acid, Peroxide value, Saponification value, Iodine value, Viscosity, and Crude Protein were significantly (P<0.05) different during the storage periods and between the extraction methods. The result showed that the physicochemical characteristics of the oil samples extracted from both local and mechanical method were FFA 7.393, 5.61; Peroxide value 1.8, 1.2, Saponification value 193.2, 189.51; Iodine value 95.71, 92.46; Specific gravity 0.9305, 0.91, Viscosity 88.68, 84.24 and Refractive index 1.473, 1.475 respectively. The oil extracted locally had higher value in FFA whereas the mechanically extracted oil had lower value even after six months of Storage. Similar trends were observed in most of the other physicochemical properties.