Deep eutectic solvent: An emerging trend for extraction of plant proteins

Nowadays, people are conscious about their protein-rich daily diet. The rising vegetarian and vegan population focuses on consuming plant protein. This uplifting demand requires exploring its extraction process in higher yield and quality. Protein extraction is highly dependent on the solvent, which is a crucial factor. Organic and aqueous solvents, along with conventional and novel techniques, have been employed in extraction over the years. Still, protein denaturation and alteration, environmental pollution, and toxicity led to further investigation. Recently, using deep eutectic solvent (DES) as an emerging solvent of protein extraction has exposed new research areas due to its high sustainability, low economic value, biodegradability, and nontoxicity. This solvent can tackle all those drawbacks and provide consumable and natural proteins without any modifications. This review enlightens the roles of extractants used for plant proteins. Besides, the introduction of DES, its composition, physiochemical properties, and preparation methods are vividly explained. Moreover, several extraction processes using DES, their mechanisms, and factors affecting efficiency are described with recent studies of plant protein extraction and plant-derived enzymes and amino acids. The study explains various back extraction techniques of DES from DES-protein mixtures. Nevertheless, some challenges and prospects should be studied to bridge the gap between innovations and applications.