EXTRACTION AND PURIFICATION OF PUMPKIN SEEDS OIL USING SOLVENT EXTRACTION METHOD

In this study extraction and purification of pumpkin seeds oil which has been distinguished as good sources of crude oils, purified oils, essential oils and other important chemicals was investigated. The pumpkin seed oil was extracted by soxhlet method using ethanol and hexane as a solvent. The oil and solvents separated by using rotary evaporator. The effect of process variables such as temperature, extraction time and particle size were optimized for maximum yield of seeds oil using response surface methodology (RSM). The maximum extracted crude oil yield (56.2%) was obtained at extraction temperature of 75℃, extraction time of 270mins and particle size of 0.25mm using ethanol as a solvent. The purifying process was used to reduce factors that affect the extracted oil chemical composition such as acid value, FFA, residuals, peroxide value and phospholipids. The value was higher in crude oil due to free FFAs present in it. Physico - chemical properties of the crude and refined oils studied at optimum yield shows specific gravity of 0.9109 and 0.9102; PH value of 4.23-5.81 and characterized by having acid value (mg KOH/g ), peroxide value (meqO2/kg), FFA, iodine value (gI2/100g oil) and saponification value (mg of KOH/g) was 1.18±0.14 and 0.246±0.013; 3.22±0.1and 0.91±0.08; 0.59±0.07 and 0.123±0.006 , 98.36± 0.51 and 96.84± 0.53; 174.3± 4.28 and 176.6 ± 3.72 of oil respectively. The presence of functional group of carbohydrate, carbocyclic, alkane, carbonyl, alkene, aliphatic amine, aromatic, alcohol and methyl ester were identified by using FT-IR. The chemical composition of crude and refined oils extracted from pumpkin seed identified using GC-MS have consisting of 2-Propenoic acid, 1-methylundecyl ester; Hexadecanoic acid; 11-(2-Cyclopenten-1-yl)undecanoic acid,(+)-; Tetradecanoic acid; Octadecanoic acid; 9-Hexadecenoic acid; 9-Octadecenoic acid; 2,6-Octadien-1-ol, 3,7- dimethyl-, (Z)-; 9,12-Octadienoic acid; 9,12-octadecadienoic acid (Z,Z)Bicyclo[10.1.0] tridec-1-ene (Table IIIa in appendix III) as the major components and possess different functional groups, which is close to essential oil reported in literature. The oil concentration of myristic acid (1.83-3.619%), palmitic acid (5.6 - 15.4%), steric acid (3.85-12.38%), oleic acid (26.93-31.7%) and lineolic acid (37.64-40.6%). Other fatty acids composition, such as C12:0, C16:1, C18:3, C20:0, C20:1, C22:0, and C22:1, were also present in concentrations less than 5.0%.