Ultrasound‐assisted extraction of favela (Cnidoscolus quercifolius) seed oil using ethanol as a solvent

In this study, the oil extraction from favela (Cnidoscolus quercifolius) seeds was evaluated using a nonconventional ultrasound-assisted extraction (UAE) method with ethanol as a solvent. UAE was performed using a 33-Box–Behnken design to evaluate the effects of the temperature, solvent-to-solid ratio, and ultrasound intensity on the yield, concentrations of tocopherols and β-sitosterol, and the antioxidant activity of the oil. The variable with the greatest influence on yield was the solvent-to-solid ratio. The highest yield (46.9 wt%) was obtained after 5 min of extraction at 60°C, 15 ml/g, and 20 W/cm2. Significant variations (p .05) from that obtained by the Soxhlet method with ethanol (~50 wt%), and the yields of total tocopherols and β-sitosterol were 11.0 and 53.4 mg per 100 g of seeds, respectively. The oils with ~76% unsaturated fatty acids were composed of linoleic (~60%), oleic (~15%), palmitic (~16%), and stearic (~7%) acids. Practical applications Seeds from favela (Cnidoscolus quercifolius), a plant from the semi-arid Brazilian ecosystem, are an interesting source of edible oil that have a high concentration of unsaturated fatty acids, mainly linoleic acid, and have significant concentrations of antioxidant compounds. The ultrasound-assisted extraction method was promising for the extraction of this vegetable oil, notably with the use of ethanol, a green solvent. This alternative technique provided high yields of oil, tocopherols, and β-sitosterol with a significant reduction in time and solvent consumption, in addition to lower temperatures, when compared to the conventional Soxhlet method.