Extraction and Characterization of Protein from sunflower meal using tailor-made deep eutectic solvents based on COSMO-RS design

This work developed a new deep eutectic solvent (DES) extraction technique for sunflower meal (SM) proteins using microwave assistance, based on the Conductor-like Screening Model for Real Solvents (COSMO-RS) screening. The research represents the first systematic comparison between the innovative green DES extractant (betaine-urea) and conventional alkali-soluble acid extraction in terms of protein extraction efficiency, structural characteristics, and techno-functional properties of SM proteins. The successful synthesis of DES was confirmed through comprehensive characterization using Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H NMR). The response surface method (RSM) was utilized to elucidate parameter interactions and establish a predictive model, leading to optimization of the extraction parameters. The optimized betaine-urea (1:1 M ratio) DES system demonstrated superior performance, achieving a protein recovery rate of 89.17 %, representing a 31.71 % improvement over conventional alkali-soluble acid extraction. Comparative analysis revealed that DES-extracted proteins exhibited enhanced solubility, emulsifying capacity, water-holding capacity, foaming properties, and thermal stability compared to alkali-soluble acid extraction counterparts. SEM revealed smoother protein surfaces in DES extracts, directly correlating with enhanced solubility for food applications. This environmentally benign extraction approach significantly reduces chemical waste generation while maintaining high extraction efficiency, establishing an effective green methodology for SM protein recovery.