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.