A Green Approach: Optimization of Ultrasound and Homogenization-Assisted Ethyl Acetate Extraction of Cottonseed Oil Using Natural Deep Eutectic Solvent as a Novel Co-solvent

Abstract NADES had an extensive spectrum of applications in the food industry and had increasing popularity for extraction techniques. The current study pioneered a novel extraction process for cottonseed oil utilizing an ultrasound and homogenization-assisted method (UHA) with a natural deep eutectic solvent (NADES) as a novel co-solvent. This proposed method is entirely aligned with the green extraction concept through the utilization of sustainable green technologies and solvents. D-Optimal mixture design was applied for the first time to discover the optimal solvent combination of NADES (Choline Chloride: Oxalic acid), ethyl acetate, and water for cottonseed oil extraction. The effect of these three solvent components on oil recovery, radical-scavenging activity (RSA), total phenolic content (TPC), free fatty acids (FFAs), and peroxide value (PV) of cottonseed oil were evaluated. The best solvent mixture combination was found by numerical optimization to be 20% NADES, 20.41% water, and 59.58% ethyl acetate. Using this ideal solvent mixture, the maximum oil recovery, RSA, and minimal FFA content of cottonseed oil were practically determined to be 90.68%, 52.21%, and 7.13%, respectively. The addition of NADES significantly enhanced oil recovery from 85.18 to 90.68% based on the initial oil content (reference). Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were utilized to ascertain the purity and assess the thermal behaviour of cottonseed oils. Moreover, by analysing and comparing the cost and energy consumption of the UHA-NADES (ultrasound and homogenization-assisted natural deep eutectic solvent) method, its feasibility for industrial applications was confirmed. This research presented a green option that includes economic advantages, diminished operational conditions/risks, and enhanced oil recovery for the vegetable oil industry by using the UHA-NADES method. Graphical Abstract