Effect of Extraction Techniques on the Physicochemical Properties, Fatty Acids Composition, and Stability of Purslane Seeds (Portulaca oleracea) Oil Compared to Soybean Seeds (Glycine max) and Sardine Fish (Sardinella maderensis) Oils

Abstract

: This study aimed to determine the physicochemical properties, fatty acids composition and thermal properties of purslane seeds oil extracted by solvent and cold-press techniques compared to soybean seeds and sardine fish oils. The obtained data indicated that extraction of purslane, soybean seeds and sardine fish oils by solvents produced significantly ( p ≤ 0.05) higher oil contents as compared to the cold-press ones. Physicochemical properties of the three oils were not affected by the extraction methods and showed good and acceptable qualities. Furthermore, no significant differences were investigated in the fatty acids composition of the oils from the two extraction techniques. Linoleic acid (C 18:2 ) was the main unsaturated fatty acid in purslane and soybean seeds oils while, eicosapentaenoic acid (C 20:5 ) was the principal unsaturated fatty acid in sardine fish oil. On the other hand, results of thermal analysis by DSC and TGA showed differences and unusual behaviors for the three examined oils. The Thermal stability results revealed complete decomposition of linoleic and linolenic acids in the three oils after exposure for 2 h at 150 ºC. Recommendations, the purslane seeds oil is a good source of omega-6 and omega-3 fatty acids. Although the solvent extraction method gave high extraction yield, the oils extracted by the cold-press would retain the genuine flavor, aroma, and nutrients. Thus cold-extraction technique is recommended to be used in oil production industry as an low cost and effective method