Parametric optimization of Argemone mexicana seed oil extraction by Box-Behnken experimental design and the oil characteristics

Abstract

Extraction of oil from Ethiopia indigenous Argemone Mexicana seed (AMS) was conducted via the soxhlet extraction technique using chloroform as the solvent. Response surface methodology based Box – Behnken experimental design (BBD) was applied to optimize the oil extraction. Three independent parameters such as seed weight, extraction time, and solvent volume, were optimized by BBD on the response variable, oil yield. Analysis of variance (ANOVA) revealed that all parameters significantly affected the oil yield. Accordingly, a high oil yield of 48.62 % was achieved at a seed weight of 6.75 g, extraction time of 3.65 h, and solvent volume of 140.3 ml. The oil was characterized by Proton Nuclear Magnetic Resonance which showed the presence of linoleic acid (59.43 %), oleic acid (24.92 %), and saturated fatty acids (15.65 %). Further characterization by Gas Chromatography Mass Spectrometry revealed the oil composition, viz. linoleic acid (58.75 %), oleic acid (25.92 %), palmitic acid (12.73 %), and stearic acid (2.25 %). This shows that fatty acid compositions are considerably comparable by both these techniques. Physico-chemical properties of the oil were determined by recognized methods, and thus reported as refractive index (1.47); viscosity (31.12 cSt); density (0.91 g/cm3); saponification value (192.8 mg KOH/g); acid value (3.5 mg KOH/g); and iodine value (118.4 g I2/100 g). In addition, Fourier Transform Infrared Spectra also showed the characteristic peaks of vegetable oils. These characteristics of AMS oil indicate that it is a potential feedstock for biofuels and biochemical products.