Green optimization strategy of sunflower oil extraction using natural deep eutectic solvent

The present work develops a green and effective method for extracting sunflower oil by combining natural deep eutectic solvents (NADESs) with the ultrasound-assisted extraction (UAE) technique. A two-stage sequential optimization strategy, integrating Box-Behnken Design (BBD) and I-Optimal Mixture Design was applied to simultaneously optimize both extraction parameters and solvent composition. BBD identified the optimal extraction conditions as 58 °C, 42 min, and a solvent-to-solid ratio of 5.15 mL/g. The I-Optimal Mixture Design established the optimum solvent composition as 14.47% NADES (ChCl:OX), 34.34% hexane, and 51.18% ethyl acetate. At these conditions 95.12% oil recovery, 77.55% radical scavenging activity (RSA), and 8.94% free fatty acids (FFA) were determined experimentally. FTIR analysis exhibited overlapping spectral bands for both fresh and recycled ChCl:OX, confirming its chemical stability and reusability potential in oil extraction processes. Principal Component Analysis (PCA) and Pearson correlation test demonstrated a strong positive correlation between oil recovery and RSA, and a negative correlation with peroxide value. This study broadens insight into green solvent, specifically NADES applications in the food industry, highlighting the potential of NADES-incorparated UAE as a hybrid solvent system that partially replaces conventional solvents and offers a more sustainable and efficient alternative for sunflower oil extraction.