New horizons for the enhanced recovery of phenolic compounds by integration of Natural Deep Eutectic Solvents and microwave-assisted extraction

Globally, approximately 2 billion tons of agricultural waste is generated each year which is rich reservoirs of bioactive compounds. Therefore, it has become increasingly important to manage and treat waste in an environmentally, economically, and socially responsible manner. These compounds can be extracted without altering their properties through the utilization of deep eutectic solvents (DES). Given their exceptional qualities aligning with green chemistry principles, DESs possess significant promise in supplanting conventional organic solvents and ionic liquids (IL). This is owing to natural deep eutectic solvents (NADES) unique physicochemical properties, which include its low toxicity, biodegradability, and biological activity. Meanwhile, conjugating DES using non-conventional extraction techniques such as microwave-assisted extraction (MAE) may reduce extraction times, increase yields, and be more environmentally friendly. The purpose of this study is to give a thorough understanding of valorization of agro-industrial food wastes by extraction of phenolic compounds using green solvents. Specifically, the research concentrates on investigating the physicochemical attributes of NADES and their synergy with the MAE method to retrieve phenolic compounds. Additionally, discussion encompassed the impact of MAE and NADES on the antioxidant, antimicrobial, and other health-promoting properties of bioactive compounds. In conclusion, the results demonstrated the feasibility of using these emerging solvents with MAE for the extraction process. Further, proper elucidation of the extraction mechanisms involved is necessary in order to expand the applications of these emerging solvents for bioactive compound recovery.