Deep eutectic solvents as new media for green extraction of food proteins: Opportunity and challenges

The constantly improved quality of life leads to increasing demand for high-quality food proteins. Thus, the high-efficiency extraction methods of food proteins are highly needed. However, the traditional alkali-solution and acid-isolation method employs a large amount of corrosive acid/alkaline solution, which not only pollutes the environment, but also causes denaturation of proteins. Therefore, developing a novel green extraction method is of great significance. Deep eutectic solvents (DES), characterized by good biodegradability, sustainability and low toxicity, have become a green solvent in the past years. Extraction of food proteins by DES can overcome the shortcomings of corrosive solvents (e.g. NaOH, HCl and H2SO4) used in traditional methods, making it a promising novel green extraction method. In this work, the information on DES was firstly recapped. Furthermore, the latest research progress on the extraction of food proteins by DES was emphatically reviewed. In addition, the challenges and future perspectives for DES-assisted extraction were discussed. Overall, the DES-based methods exhibit high extraction efficiency in extracting animal and plant proteins, amino acids, and enzymes, while the extracted proteins were non-denatured. However, DES-based protein extraction method still faces some challenges, such as high viscosity, poor extraction selectivity and inefficient back-extraction method. The present work can provide a theoretical reference for applying DES in the green extraction of food proteins.