Evaluating the physicochemical properties of camelina (Camelina sativa) seed oil obtained through optimized ultrasonic-assisted extraction

Abstract

The primary limitation associated with oil extraction through pressing is the considerable amount of residual oil in the cake. Therefore, this study focused on employing ultrasound waves to decrease the oil content in camelina seeds. For this purpose, three ultrasound treatment durations (15 to 45 min) were applied, and oil was immediately extracted from the seeds using a screw press at varying speeds (11 to 55 rpm). Various physicochemical tests were conducted on the extracted oil. After identifying the optimal treatments, the fatty acid content and oxidative stability of the samples were determined. Results indicated that longer ultrasound treatment durations led to higher acidity and peroxide values in the samples. In contrast, the oil extraction efficiency and total phenol content initially increased and then declined. Increasing the rotational speed of the screw press decreased total phenol efficiency but increased acidity and peroxide values. Ultrasound pretreatment had no effect on the refractive index of the oils. Based on the process optimization results, ultrasound pretreatment achieved optimal oil extraction from camelina seeds at a treatment time of 21.02 min and a screw press speed of 11 rpm. Under these conditions, the extraction parameters included an efficiency of 34.5 %, an oil acidity of 0.394 % (as oleic acid), a peroxide value of 0.97 meqO₂/kg oil, a total phenol content of 122.68 ppm, and a refractive index of 1.4750. Ultrasound pretreatment also reduced oxidative stability from 3.75 h to 3.13 h. Gas chromatography results showed that linolenic acid was the major fatty acid in both treated and control oil samples. As a result, the findings demonstrate that ultrasound pretreatment is an effective method for extracting oil from camelina seeds.