Extraction, Process Optimization and Characterization of Garden Cress Seed Oil Grown in Ethiopia

Garden cress (Lepidium sativum) seeds, from the Brassicaceae family, are rich in essential fatty acids and possess medicinal properties due to their phenol and flavonoid content. Oil extraction was performed using Soxhlet extraction with hexane as the solvent, investigating the effects of heat treatment, particle size, and extraction time on oil yield. A maximum predicted oil yield of 28.65% was achieved using Design Expert software (version 12.0.0), validated with an actual yield of 28.53%. The physical properties of the oil were determined as density (700 ± 10 kg/m³), viscosity (67.65 ± 1.15 mm²/s), and refractive index (1.47). Chemical properties included a free fatty acid value of 0.64%, peroxide value of 3.59 meq/kg, iodine value of 127 g I₂/100 g, and saponification value of 183.84 mg KOH/g. GC-MS analysis revealed that the oil contains 47.81% monounsaturated, 37.88% polyunsaturated, and 14.26% saturated fatty acids.