Sesame cake is a by‐product of sesame oil industry. In this study, the effect of extraction methods (maceration and sonication) and solvents (ethanol, methanol, ethanol/water (50:50), methanol/water (50:50), and water) on the antioxidant properties of sesame cake extracts are evaluated to determine the most suitable extraction method for optimal use of this product. Total phenolic content is measured according to the Folin–Ciocalteu method and antioxidant activities of each extract are evaluated with the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), β‐carotene bleaching, and ferric reducing/antioxidant power (FRAP) methods. The highest amount of total phenolic compounds is observed in ethanol‐ultrasonic extract with the amount of 88.89 mg/g gallic acid equivalent. Methanol‐ultrasonic extract with the amount of 88.475% indicates the highest activity in scavenging DPPH free radicals. In β‐carotene‐linoleic acid system, ethanol‐ultrasonic extract indicates the highest inhibition percent of 45.64. In FRAP assay, ethanol/water (50:50)‐maceration and ethanol/water (50:50)‐ultrasonic extracts with the absorption of 1.132 and 1.0745 nm indicate the highest antioxidant activity.

In this study, the effect of solvent ratio of hexane to isopropanol (0:100, 50:50, and 100:0 v/v%), extraction temperature (30, 45, and 60°C), and time (30, 60, and 90 min) were investigated on the oil extraction efficiency, total phenol content, DPPH radical scavenging, peroxide value, and oil color index. Extraction conditions were optimized by response surface methodology and Box–Behnken design. The optimal conditions were obtained as hexane‐to‐isopropanol ratio of approximately 3:2, temperature of 40.26°C, and ultrasonication time of 54.40 min. Then, the hemp seed oil was extracted under the optimal conditions. The optimal predicted contents for oil yield (31.22%), total phenolics (3.19 mg GA/g oil), DPPH inhibition (73.86%), peroxide (4.62 meq/kg), and color index (28.2) were agreed with the predicted conditions because the RSE values were less than 5%. Hemp seed oil can be used extensively due to its high nutritional values, and antioxidant potential and ultrasound can improve oil extraction as a simple and fast method.